springBoot
一、概述
1.什么是spring boot
Spring Boot是Spring项目中的一个子工程,与我们所熟知的Spring-framework 同属于spring的产品:
其最主要作用就是帮助开发人员快速的构建庞大的spring项目,并且尽可能的减少一切xml配置,做到开箱即用,迅速上手,让开发人员关注业务而非配置。
2.spring boot的特点
1.自动配置:不需要再关注各个框架的整合配置,springboot全部都已经配置好了。
2.起步依赖:我们在需要使用某个框架的时候,直接添加这个框架的启动器依赖即可,不需要在关注jar包的冲突和整合。
3.目的
用来简化spring应用的初始搭建以及开发过程。
- 为所有spring开发提供一个更快更广泛的入门体验。
- 零配置。没有冗余代码生成和xml强制配置,遵循“约定大于配置”
- 集成了大量常用的第三方库的配置,spring boot应用为这些第三方库提供了几乎可以零配置的开箱即用的能力。
- 提供一系列大型项目常用的非功能性,如嵌入服务器等。
4.好处
简单、快速、方便
5.优势
使用Java开发程序 , 一直困扰我们的就是臃肿、麻烦。搭建项目的过程相当复杂 , 我们需要考虑很多问题 , 主要的问题有如下两点 :
- 复杂的配置
- 混乱的依赖管理
Spring Boot帮我们解决了这个些, 我们在使用Spring Boot开发时, 不需要关注各种复杂的整合配置 , 也不用关注各个库之间的依赖及冲突问题 , Spring Boot已经默认帮我们整合配置好了 !
二、springboot之helloworld
1.需求
访问 http://localhost:8080/hello
输出 “Hello Spring Boot”
2.步骤
-
创建Maven工程
-
加依赖(springboot父工程依赖 , web启动器依赖)
扫描二维码关注公众号,回复: 13435198 查看本文章<!--spring boot 父工程依赖--> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.2.2.RELEASE</version> </parent> <!--web 启动器--> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> </dependencies> 复制代码
配置jdk版本
<properties> <java.version>1.8</java.version> </properties> 复制代码
思考: 为什么我们这里仅仅配置了这么一个变量 , 项目的JDK版本就会改变呢 ?
因为jdk插件已经在父工程中定义好了 , 默认会读取${java.version}变量值
-
写启动引导类(springboot项目运行的入口)
import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class Application { public static void main(String[] args) { SpringApplication.run(Application.class,args); } } 复制代码
-
编写处理器Controller
import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class HelloController { @RequestMapping("/hello") public String sayHello(){ return "hello spring boot!!" ; } } 复制代码
-
启动项目
运行启动类的main方法
3.问题
1.为什么我们在添加启动器的时候不需要在启动器的坐标中指定版本?
答案:因为我们指定了项目的父工程,在spring-boot-starter-parent中已经通过Maven的版本锁定了Jar包的版本,所以就不需要再指定了。
2.为什么我们就添加一个启动器依赖,项目就可以运行起来了,运行项目所需要的Jar包从何而来?
答案:因为我们添加了这个启动器的依赖,它已经把自己运行所需要的必要包集成在这个启动器中,通过Maven的依赖传递性,将这些包都依赖到咱们的项目里了。
4.配置文件详解
springboot支持两种类型的配置文件
- properties属性配置文件
- yaml配置文件
配置文件必须放在项目的类加载目录下, 并且名字必须是application开头
springboot项目在运行的时候会自动加载这些配置文件。
可以在spring-boot-autoconfigure-2.2.2.RELLEASE.jar的META-INF目录下找到additional-spring-configuration-metadata.json搜索server.port,显示默认的端口是8080.
为什么可以在resources下创建application.properties文件?
我们查看springboot的启动依赖
按住ctrl键点击spring-boot-starter-parent
可以在父工程中看到
<build> <resources> <resource> <filtering>true</filtering> <directory>${basedir}/src/main/resources</directory> <include>**/application*.yml</include> <include>**/application*.yaml</include> <include>**/application*.properties</include> </resource> </resources> </build> 复制代码
5.如何主动读取配置文件到类变量
要使用@Value("${属性名}")
如下:
在 resource
文件夹下面新建 application.properties
配置文件
spring.jdbc.datasource.driverClassName=com.mysql.jdbc.driver
spring.jdbc.datasource.url=jdbc:mysql:///springboot_01
spring.jdbc.datasource.username=root
spring.jdbc.datasource.password=123456
复制代码
创建类 DataSourceProperties
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component
public class DataSourceProperties {
@Value("${spring.jdbc.datasource.driverClassName}")
private String driverClassName;
@Value("${spring.jdbc.datasource.url}")
private String url;
@Value("${spring.jdbc.datasource.username}")
private String username;
@Value("${spring.jdbc.datasource.password}")
private String password;
// 生成get set 和 toString方法
}
复制代码
三、YAML配置文件
1.什么是YAML?
YAML是一种配置文件格式
2.语法
1.数据结构用树形结构呈现,通过缩进来表示层级,
2.连续的项目通过减号 ” - ” 来表示
3.键值结构里面的key/value对用冒号 ” : ” 来分隔,冒号后要加上一个空格才能跟属性值。
4.YAML配置文件的扩展名是yaml 或 yml
如果要修改前面那个properties文件为yaml文件
spring:
jdbc:
datasource:
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql:///springboot_01
username: root
password: 123456
复制代码
yml配置文件的特征:
- 树状层级结构展示配置项
- 配置项之间如果有关系的话需要分行,空两格
- 配置项如果有值的话,那么需要在:之后空一格再写配置项值;
yaml与peoperties配置文件处理展示像是不相同以外,其他功能和作用都是一样的。
3.多环境profile切换配置
在实际开发中,因为开发环境的变化,我们需要修改配置文件中某一个配置项的值(比如之前himysql数据库,切换成oracle数据库)
项目开发完成需要上线时,需要把一些环境改成正式环境(开发,测试,上线,多环境切换)
解决方案:使用profiles拆分配置
spring boot项目中允许使用多个yaml配置文件。
这些文件名称必须为**application-***.yml
**,并且在application.yml中激活。
具体实施
创建application-dev.yml文件如下:
spring:
jdbc:
datasource:
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql:///springboot
username: root
password: 123456
复制代码
创建application-pro.yml
文件如下:
spring:
jdbc:
datasource:
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql:///business
username: business
password: business
复制代码
在application.yml文件中添加如下配置:
spring:
profiles:
active: dev
复制代码
此时生效的文件就是application-dev.yml配置文件。
注意:
如果properties和yml文件都存在,不存在spring.profiles.active设置,如果有重叠属性,默认以properties文件优先.
如果设置了spring.profiles.active,并且有重叠属性,以active设置优先。
可以在两种文件中分别增加server.port属性指定不同的端口,启动项目查看控制台端口号进行测试。
四、Spring Boot 的自动配置原理
1.@SpringBootApplication注解
①@SpringBootConfiguration
含义:代表这个类就是一个配置类,本质上就是一个@Configuration注解
②ComponentScan
组件扫描,默认扫描启动类所在包以及子包的类身上的注解。
③EnableAutoConfiguration
自动配置注解,添加了此注解会自动去读取spring.factories配置文件中的自动配置类。
2.@ConfigurationProperties注解
@ConfigurationProperties是SpringBoot提供的重要注解,他可以将一些配置属性批量注入到bean对象。
注入配置属性
方式一:使用@Value一个个注入
这种方式,如果属性特别多,一个一个注入非常麻烦。
方式二:使用@ConfigurationProperties批量注入【和@EnableConfigurationProperties配合使用】
@Component
@ConfigurationProperties(prefix = "spring.jdbc.datasource")
public class DataSourceProperties2 {
private String driverClassName;
private String url;
private String username;
private String password;
// 省略getter和setter.....
}
复制代码
- 在类上通过@ConfigurationProperties注解声明该类要读取属性配置。
- prefix="spring.jdbc.datasource"读取属性文件中前缀为spring.jdbc.datasource的值。前缀和属性名称和配置文件中的key必须要一致才能注入成功
- Spring Boot默认读取application.properties属性文件
开启@ConfigurationProperties注解使用
@Controller
@EnableConfigurationProperties(DataSourceProperties2.class)
public class HelloController {
@Autowired
private DataSourceProperties2 dataSourceProperties2 ;
@RequestMapping(path = "/hello")
@ResponseBody
public String sayHello(){
System.out.println(dataSourceProperties2);
return "hello spring boot";
}
}
使用@EnableConfi
复制代码
使用@EnableConfigurationProperties(DataSourceProperties2.class),开启DataSoutceProperties2身上的@ConfigurationProperties注解,他就会生效了,就能够帮我们注入数据了。
可能出现错误
Spring Boot Configuration Annotation Processor not found in classpath
。解决方法:
在pom文件中加入依赖
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <optional>true</optional> </dependency> 复制代码
3.条件化配置注解
我们看到自动配置类上有一些ConditionalXxx注解,这些注解的作用就是进行条件化选择。
所谓条件化选择就是如果满足条件,该配置类就生效,如果不满足该配置类就不生效。
常用的条件化选座注解如下:
注解 | 作用 |
---|---|
@ConditionalOnBean | 如果存在某个Bean, 配置类生效 |
@ConditionalOnMissingBean | 如果不存在某个Bean, 配置类生效 |
@ConditionalOnClass | 如果存在某个类, 配置类生效 |
@ConditionalOnMissingClass | 如果不存在某个类, 配置类生效 |
@ConditionalOnProperty | 如果存在某个属性配置, 配置类生效 |
@ConditionalOnWebApplication | 如果是一个web应用, 配置类生效 |
@ConditionalOnNotWebApplication | 如果不是一个web应用, 配置类生效 |
因为我们配置了DispatcherServlet满足上面定义的条件,所以WebMvcAutoConfiguration会生效,那么WebMvcAutoConfiguration自动配置类中帮我们配置了什么?
- 视图解析器(触发
public InternalResourceViewResolver defaultViewResolver()
或public BeanNameViewResolver beanNameViewResolver()
方法) - 处理器适配器(
public RequestMappingHandlerAdapter requestMappingHandlerAdapter()
方法)
这些配置都是我们之前在学习SpringMVC时需要自己配置的,现在Spring Boot框架都已经帮我们提前配置好了,所以我们才能使用的那么方便。
4.自动配置原理
1.加载spring.factories
在SpringApplication类构建的时候,有这样一段初始化代码:
public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {
this.sources = new LinkedHashSet();
this.bannerMode = Mode.CONSOLE;
this.logStartupInfo = true;
this.addCommandLineProperties = true;
this.addConversionService = true;
this.headless = true;
this.registerShutdownHook = true;
this.additionalProfiles = new HashSet();
this.isCustomEnvironment = false;
this.lazyInitialization = false;
this.resourceLoader = resourceLoader;
Assert.notNull(primarySources, "PrimarySources must not be null");
this.primarySources = new LinkedHashSet(Arrays.asList(primarySources));
this.webApplicationType = WebApplicationType.deduceFromClasspath();
this.setInitializers(this.getSpringFactoriesInstances(ApplicationContextInitializer.class));
this.setListeners(this.getSpringFactoriesInstances(ApplicationListener.class));
this.mainApplicationClass = this.deduceMainApplicationClass();
}
复制代码
注意 this.setInitializers(this.getSpringFactoriesInstances(ApplicationContextInitializer.class));
点击进入getSpringFactoriesInstances
方法
private <T> Collection<T> getSpringFactoriesInstances(Class<T> type) {
return this.getSpringFactoriesInstances(type, new Class[0]);
}
复制代码
紧接着跟入getSpringFactoriesInstances
方法
private <T> Collection<T> getSpringFactoriesInstances(Class<T> type, Class<?>[] parameterTypes, Object... args) {
ClassLoader classLoader = this.getClassLoader();
Set<String> names = new LinkedHashSet(SpringFactoriesLoader.loadFactoryNames(type, classLoader));
List<T> instances = this.createSpringFactoriesInstances(type, parameterTypes, classLoader, args, names);
AnnotationAwareOrderComparator.sort(instances);
return instances;
}
复制代码
可以看到Set<String> names = new LinkedHashSet(SpringFactoriesLoader.loadFactoryNames(type, classLoader));
这条代码。能够发现loadFactoryNames()
尝试加载一些FactoryName,然后利用createSpringFactoriesInstances
将这些加载到的类名进行实例化。然后继续跟进loadFactoryNames方法:
public static List<String> loadFactoryNames(Class<?> factoryType, @Nullable ClassLoader classLoader) {
String factoryTypeName = factoryType.getName();
return (List)loadSpringFactories(classLoader).getOrDefault(factoryTypeName, Collections.emptyList());
}
复制代码
观察返回时调用的loadSpringFactories
方法
private static Map<String, List<String>> loadSpringFactories(@Nullable ClassLoader classLoader) {
MultiValueMap<String, String> result = (MultiValueMap)cache.get(classLoader);
if (result != null) {
return result;
} else {
try {
Enumeration<URL> urls = classLoader != null ? classLoader.getResources("META-INF/spring.factories") : ClassLoader.getSystemResources("META-INF/spring.factories");
LinkedMultiValueMap result = new LinkedMultiValueMap();
while(urls.hasMoreElements()) {
URL url = (URL)urls.nextElement();
UrlResource resource = new UrlResource(url);
Properties properties = PropertiesLoaderUtils.loadProperties(resource);
Iterator var6 = properties.entrySet().iterator();
while(var6.hasNext()) {
Entry<?, ?> entry = (Entry)var6.next();
String factoryTypeName = ((String)entry.getKey()).trim();
String[] var9 = StringUtils.commaDelimitedListToStringArray((String)entry.getValue());
int var10 = var9.length;
for(int var11 = 0; var11 < var10; ++var11) {
String factoryImplementationName = var9[var11];
result.add(factoryTypeName, factoryImplementationName.trim());
}
}
}
cache.put(classLoader, result);
return result;
} catch (IOException var13) {
throw new IllegalArgumentException("Unable to load factories from location [META-INF/spring.factories]", var13);
}
}
}
复制代码
发现此处会利用类加载器加载一个文件:META-INF/factories。我们知道,ClassLoader默认是从classpath下读取的文件,因此,SpringBoot会在初始化的时候,加载所有classpath:META-INF/spring.factories文件,包括jar包当中的。而在Spring的一个依赖包:spring-boot-autoconfigure中,就有这样一个文件。
我们引入的任何第三方启动器,只要实现自动配置,也都会有类似文件。
2.读取自动配置类
打开这个spring.factories
# Initializers
org.springframework.context.ApplicationContextInitializer=\
org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer,\
org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener
# Application Listeners
org.springframework.context.ApplicationListener=\
org.springframework.boot.autoconfigure.BackgroundPreinitializer
# Auto Configuration Import Listeners
org.springframework.boot.autoconfigure.AutoConfigurationImportListener=\
org.springframework.boot.autoconfigure.condition.ConditionEvaluationReportAutoConfigurationImportListener
# Auto Configuration Import Filters
org.springframework.boot.autoconfigure.AutoConfigurationImportFilter=\
org.springframework.boot.autoconfigure.condition.OnBeanCondition,\
org.springframework.boot.autoconfigure.condition.OnClassCondition,\
org.springframework.boot.autoconfigure.condition.OnWebApplicationCondition
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\
org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\
org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,\
org.springframework.boot.autoconfigure.cloud.CloudServiceConnectorsAutoConfiguration,\
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,\
org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration,\
org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveRestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jdbc.JdbcRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.jest.JestAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.rest.RestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration,\
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration,\
org.springframework.boot.autoconfigure.h2.H2ConsoleAutoConfiguration,\
org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastJpaDependencyAutoConfiguration,\
org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration,\
org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration,\
org.springframework.boot.autoconfigure.influx.InfluxDbAutoConfiguration,\
org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration,\
org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration,\
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.XADataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration,\
org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JndiConnectionFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.activemq.ActiveMQAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.artemis.ArtemisAutoConfiguration,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration,\
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration,\
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration,\
org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration,\
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration,\
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\
org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketMessagingAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketRequesterAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketServerAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketStrategiesAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityFilterAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveUserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.rsocket.RSocketSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyAutoConfiguration,\
org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration,\
org.springframework.boot.autoconfigure.session.SessionAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.servlet.OAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.reactive.ReactiveOAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration,\
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration,\
org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.ClientHttpConnectorAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.reactive.WebSocketReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketMessagingAutoConfiguration,\
org.springframework.boot.autoconfigure.webservices.WebServicesAutoConfiguration,\
org.springframework.boot.autoconfigure.webservices.client.WebServiceTemplateAutoConfiguration
# Failure analyzers
org.springframework.boot.diagnostics.FailureAnalyzer=\
org.springframework.boot.autoconfigure.diagnostics.analyzer.NoSuchBeanDefinitionFailureAnalyzer,\
org.springframework.boot.autoconfigure.flyway.FlywayMigrationScriptMissingFailureAnalyzer,\
org.springframework.boot.autoconfigure.jdbc.DataSourceBeanCreationFailureAnalyzer,\
org.springframework.boot.autoconfigure.jdbc.HikariDriverConfigurationFailureAnalyzer,\
org.springframework.boot.autoconfigure.session.NonUniqueSessionRepositoryFailureAnalyzer
# Template availability providers
org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider=\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.mustache.MustacheTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.web.servlet.JspTemplateAvailabilityProvider
复制代码
可以发现以EnableAutoConfigutation接口为key的一系列配置,key所对应的值,就是所有的自动配置类,可以在当前的jar包中找到这些自动配置类:
几乎涵盖了现在主流的开源框架,我们可以从这里查看SpringMVC的自动配置类。
我们就找到了springmvc的自动配置类
3.默认属性配置
配置类找到了,那么这些默认配置的属性来自哪里?
例如:我们配置视图解析器的时候需要配置前缀后后缀,那么这些配置在哪里?
@Bean
@ConditionalOnMissingBean
public InternalResourceViewResolver defaultViewResolver() {
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setPrefix(this.mvcProperties.getView().getPrefix());
resolver.setSuffix(this.mvcProperties.getView().getSuffix());
return resolver;
}
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通过这段源码发现,这个配置是this.mvcProperties.getView()
中获取的。查看这个方法。
public WebMvcProperties.View getView() {
return this.view;
}
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发现读取的是类变量
private final WebMvcProperties.View view;
复制代码
这个View类型封装着前缀和后缀
public static class View {
private String prefix;
private String suffix;
public View() {
}
public String getPrefix() {
return this.prefix;
}
public void setPrefix(String prefix) {
this.prefix = prefix;
}
public String getSuffix() {
return this.suffix;
}
public void setSuffix(String suffix) {
this.suffix = suffix;
}
}
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可以看到,前缀和后缀变量的值默认是null。
4.覆盖默认属性配置
如果我们想要自己指定视图的前缀和后缀?
我们可以再看WebMvcAutoConfiguration这个类的静态内部类WebMvcAutoConfigurationAdapter
上一个声明,发现这个类上面有这样一个注解@EnableConfigurationProperties({WebMvcProperties.class, ResourceProperties.class})
。
@Configuration(
proxyBeanMethods = false
)
@Import({WebMvcAutoConfiguration.EnableWebMvcConfiguration.class})
@EnableConfigurationProperties({WebMvcProperties.class, ResourceProperties.class})
@Order(0)
public static class WebMvcAutoConfigurationAdapter implements WebMvcConfigurer {
private static final Log logger = LogFactory.getLog(WebMvcConfigurer.class);
private final ResourceProperties resourceProperties;
private final WebMvcProperties mvcProperties;
private final ListableBeanFactory beanFactory;
private final ObjectProvider<HttpMessageConverters> messageConvertersProvider;
final WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer;
public WebMvcAutoConfigurationAdapter(ResourceProperties resourceProperties, WebMvcProperties mvcProperties, ListableBeanFactory beanFactory, ObjectProvider<HttpMessageConverters> messageConvertersProvider, ObjectProvider<WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider) {
this.resourceProperties = resourceProperties;
this.mvcProperties = mvcProperties;
this.beanFactory = beanFactory;
this.messageConvertersProvider = messageConvertersProvider;
this.resourceHandlerRegistrationCustomizer = (WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer)resourceHandlerRegistrationCustomizerProvider.getIfAvailable();
}
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
this.messageConvertersProvider.ifAvailable((customConverters) -> {
converters.addAll(customConverters.getConverters());
});
}
public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
if (this.beanFactory.containsBean("applicationTaskExecutor")) {
Object taskExecutor = this.beanFactory.getBean("applicationTaskExecutor");
if (taskExecutor instanceof AsyncTaskExecutor) {
configurer.setTaskExecutor((AsyncTaskExecutor)taskExecutor);
}
}
Duration timeout = this.mvcProperties.getAsync().getRequestTimeout();
if (timeout != null) {
configurer.setDefaultTimeout(timeout.toMillis());
}
}
public void configurePathMatch(PathMatchConfigurer configurer) {
configurer.setUseSuffixPatternMatch(this.mvcProperties.getPathmatch().isUseSuffixPattern());
configurer.setUseRegisteredSuffixPatternMatch(this.mvcProperties.getPathmatch().isUseRegisteredSuffixPattern());
}
public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
Contentnegotiation contentnegotiation = this.mvcProperties.getContentnegotiation();
configurer.favorPathExtension(contentnegotiation.isFavorPathExtension());
configurer.favorParameter(contentnegotiation.isFavorParameter());
if (contentnegotiation.getParameterName() != null) {
configurer.parameterName(contentnegotiation.getParameterName());
}
Map<String, MediaType> mediaTypes = this.mvcProperties.getContentnegotiation().getMediaTypes();
mediaTypes.forEach(configurer::mediaType);
}
@Bean
@ConditionalOnMissingBean
public InternalResourceViewResolver defaultViewResolver() {
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setPrefix(this.mvcProperties.getView().getPrefix());
resolver.setSuffix(this.mvcProperties.getView().getSuffix());
return resolver;
}
@Bean
@ConditionalOnBean({View.class})
@ConditionalOnMissingBean
public BeanNameViewResolver beanNameViewResolver() {
BeanNameViewResolver resolver = new BeanNameViewResolver();
resolver.setOrder(2147483637);
return resolver;
}
@Bean
@ConditionalOnBean({ViewResolver.class})
@ConditionalOnMissingBean(
name = {"viewResolver"},
value = {ContentNegotiatingViewResolver.class}
)
public ContentNegotiatingViewResolver viewResolver(BeanFactory beanFactory) {
ContentNegotiatingViewResolver resolver = new ContentNegotiatingViewResolver();
resolver.setContentNegotiationManager((ContentNegotiationManager)beanFactory.getBean(ContentNegotiationManager.class));
resolver.setOrder(-2147483648);
return resolver;
}
@Bean
@ConditionalOnMissingBean
@ConditionalOnProperty(
prefix = "spring.mvc",
name = {"locale"}
)
public LocaleResolver localeResolver() {
if (this.mvcProperties.getLocaleResolver() == org.springframework.boot.autoconfigure.web.servlet.WebMvcProperties.LocaleResolver.FIXED) {
return new FixedLocaleResolver(this.mvcProperties.getLocale());
} else {
AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
localeResolver.setDefaultLocale(this.mvcProperties.getLocale());
return localeResolver;
}
}
public MessageCodesResolver getMessageCodesResolver() {
if (this.mvcProperties.getMessageCodesResolverFormat() != null) {
DefaultMessageCodesResolver resolver = new DefaultMessageCodesResolver();
resolver.setMessageCodeFormatter(this.mvcProperties.getMessageCodesResolverFormat());
return resolver;
} else {
return null;
}
}
public void addFormatters(FormatterRegistry registry) {
ApplicationConversionService.addBeans(registry, this.beanFactory);
}
public void addResourceHandlers(ResourceHandlerRegistry registry) {
if (!this.resourceProperties.isAddMappings()) {
logger.debug("Default resource handling disabled");
} else {
Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
CacheControl cacheControl = this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl();
if (!registry.hasMappingForPattern("/webjars/**")) {
this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{"/webjars/**"}).addResourceLocations(new String[]{"classpath:/META-INF/resources/webjars/"}).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
}
String staticPathPattern = this.mvcProperties.getStaticPathPattern();
if (!registry.hasMappingForPattern(staticPathPattern)) {
this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{staticPathPattern}).addResourceLocations(WebMvcAutoConfiguration.getResourceLocations(this.resourceProperties.getStaticLocations())).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
}
}
}
private Integer getSeconds(Duration cachePeriod) {
return cachePeriod != null ? (int)cachePeriod.getSeconds() : null;
}
private void customizeResourceHandlerRegistration(ResourceHandlerRegistration registration) {
if (this.resourceHandlerRegistrationCustomizer != null) {
this.resourceHandlerRegistrationCustomizer.customize(registration);
}
}
@Bean
@ConditionalOnMissingBean({RequestContextListener.class, RequestContextFilter.class})
@ConditionalOnMissingFilterBean({RequestContextFilter.class})
public static RequestContextFilter requestContextFilter() {
return new OrderedRequestContextFilter();
}
}
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再点进去看这两个配置类WebMvcProperties.class, 配置类身上使用ConfigurationProperties读取配置,前缀是spring.mvc
@ConfigurationProperties(
prefix = "spring.mvc"
)
public class WebMvcProperties {
//...
}
复制代码
而ResourceProperties.class读取的配置前缀是spring.resources
@ConfigurationProperties(
prefix = "spring.resources",
ignoreUnknownFields = false
)
public class ResourceProperties {
//...
}
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所以如果我们再配置文件中配置spring.mvc前缀开头的配置,就可以将自己配置的数据注入到这个对象的属性中。注意,由于@ConfigurationProperties是批量注入,我们在写配置属性时,要和这个类的前缀+属性名完全一致,否则注入不成功。
例如
spring:
mvc:
view:
prefix: /WEB-INF/
suffix: .jsp
复制代码
或者修改端口号
server:
port: 10000
复制代码
5.自定义启动器
1.需求介绍
定义一个连接池启动器,当用户引入了连接池启动依赖之后,项目中就已经自动配置了连接池。
2.步骤分析
-
建启动器项目
-
添加启动器相关依赖
-
创建属性配置类
-
创建自动配置类
-
编写自动配置文件(spring.factories)
-
使用自定义的启动器
3.代码实现
1.创建项目,引入依赖
创建项目spring-boot-jdbc-starter
pom.xml
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.2.RELEASE</version>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<!--引入spring‐boot‐starter;所有starter的基本配置-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<!--自动配置连接池-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.12</version>
</dependency>
<dependency>
<groupId>c3p0</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.1.2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
复制代码
2.创建属性配置类
import org.springframework.boot.context.properties.ConfigurationProperties;
@Component
@ConfigurationProperties(prefix = "spring.jdbc.datasource")
public class DataSourceProperties {
private String driverClassName ;
private String url;
private String username;
private String password;
// 生成set get toString方法
}
复制代码
3.创建自动配置类
import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.sql.DataSource;
@SpringBootConfiguration
@EnableConfigurationProperties(DataSourceProperties.class)
public class DataSourceAutoConfiguration {
@Autowired
private DataSourceProperties dataSourceProperties ;
@Bean
public DataSource createDataSource(){
DruidDataSource dataSource = new DruidDataSource();
dataSource.setDriverClassName(dataSourceProperties.getDriverClassName());
dataSource.setUrl(dataSourceProperties.getUrl());
dataSource.setUsername(dataSourceProperties.getUsername());
dataSource.setPassword(dataSourceProperties.getPassword());
return dataSource;
}
}
复制代码
4.编写自动配置属性文件
在resources文件夹下面新建META-INF/spring.factories
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.dyy.autoconfig.DataSourceAutoConfiguration
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做完之后要注意在Maven中执行install,安装项目。
5.使用自定义启动器
在新建的项目中引入我们自己的自定义启动器依赖
<dependency>
<groupId>com.dyy</groupId>
<artifactId>spring-boot-jdbc-starter</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
复制代码
配置连接池信息。
新建application-datasource.yml
spring:
jdbc:
datasource:
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql:///springboot_01
username: root
password: 123456
复制代码
激活配置文件application.yml
spring:
profiles:
active: datasource
复制代码
进入连接池,查看连接池属性
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.sql.DataSource;
@RestController
public class HelloController {
@Autowired
private DataSource dataSource ;
@RequestMapping(path = "/hello")
public String sayHello() {
System.out.println(dataSource.getClass());//打印DruidDataSource数据源
return "Hello Spring Boot ! " ;
}
}
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6.多种数据源
如果想让我们的启动器支持多种数据源。例如C3P0和Druid,根据配置进行选择,就可以使用条件选择进行实现。例如:如下配置中,有两个创建连接池的配置,一个是C3p0,一个是Druid,如何能够根据配置文件自动选择呢?
修改配置文件application-datasource.yml
spring:
jdbc:
datasource:
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql:///springboot_01
username: root
password: root
type: druid # 数据源类型
复制代码
- 如果配置文件中配置了spring.jdbc.datasource.type=c3p0使用c3p0数据源
- 如果配置文件中配置了spring.jdbc.datasource.type=druid使用druid数据源。
在项目 spring-boot-jdbc-starter
, 添加创建 c3p0
方法
package com.dyy.autoconfig;
import com.alibaba.druid.pool.DruidDataSource;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.sql.DataSource;
@Configuration
@EnableConfigurationProperties(DataSourceProperties.class)
public class DataSourceAutoConfiguratioin {
@Autowired
private DataSourceProperties dataSourceProperties ;
@Bean
@ConditionalOnProperty(value = "spring.jdbc.datasource.type",havingValue = "druid")
public DataSource createDataSource(){
DruidDataSource dataSource = new DruidDataSource();
dataSource.setDriverClassName(dataSourceProperties.getDriverClassName());
dataSource.setUrl(dataSourceProperties.getUrl());
dataSource.setUsername(dataSourceProperties.getUsername());
dataSource.setPassword(dataSourceProperties.getPassword());
return dataSource;
}
@Bean
@ConditionalOnProperty(value = "spring.jdbc.datasource.type",havingValue = "c3p0")
public DataSource createC3P0DataSource() throws Exception{
ComboPooledDataSource dataSource = new ComboPooledDataSource();
dataSource.setDriverClass(dataSourceProperties.getDriverClassName());
dataSource.setJdbcUrl(dataSourceProperties.getUrl());
dataSource.setUser(dataSourceProperties.getUsername());
dataSource.setPassword(dataSourceProperties.getPassword());
return dataSource;
}
}
复制代码
我们可以使用条件选择实现 , 如下图所示
@ConditionalOnProperty(value = "spring.jdbc.datasource.type",havingValue = "druid") install安装
spring-boot-jdbc-starter, 运行
springboot_01
修改配置文件,重新install,再次请求。
五、spring boot常用启动器
1.SpringBoot整合MVC
创建项目 springboot_02_mvc
1.依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.2.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
复制代码
2.新建入口程序类
package com.dyy;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class,args);
}
}
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3.新建javabean
public class User {
private String username ;
private String password ;
private Integer age ;
private String sex ;
…
}
复制代码
4.新建UserController
import com.dyy.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import java.util.ArrayList;
import java.util.List;
@Controller
@RequestMapping(path = "/user")
public class UserController {
@RequestMapping(path = "/findAll")
@ResponseBody
public List<User> findAll(){
//查询所有
List<User> users = new ArrayList<User>();
User user1 = new User();
user1.setUsername("杨过");
user1.setPassword("123456");
user1.setAge(18);
user1.setSex("男");
User user2 = new User();
user2.setUsername("杨过");
user2.setPassword("123456");
user2.setAge(18);
user2.setSex("男");
User user3 = new User();
user3.setUsername("杨过");
user3.setPassword("123456");
user3.setAge(18);
user3.setSex("男");
users.add(user1);
users.add(user2);
users.add(user3);
return users ;
}
}
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运行程序。
2.静态资源目录
之前,开发web项目,如果是普通的项目金泰资源可以放在项目的webapp目录下。
现在使用Spring Boot做开发,项目中没有webapp目录,我们的项目是一个jar工程,那么就没有webapp,我么的静态资源该放哪里?
在springboot 中有一个叫做ResourceProperties得类,里面就定义了静态资源的默认查找路径。
@ConfigurationProperties(
prefix = "spring.resources",
ignoreUnknownFields = false
)
public class ResourceProperties {
private static final String[] CLASSPATH_RESOURCE_LOCATIONS = new String[]{"classpath:/META-INF/resources/", "classpath:/resources/", "classpath:/static/", "classpath:/public/"};
private String[] staticLocations;
private boolean addMappings;
private final ResourceProperties.Chain chain;
private final ResourceProperties.Cache cache;
public ResourceProperties() {
this.staticLocations = CLASSPATH_RESOURCE_LOCATIONS;
this.addMappings = true;
this.chain = new ResourceProperties.Chain();
this.cache = new ResourceProperties.Cache();
}
//...
}
复制代码
可以看到默认的静态资源路径为:
- classpath:/META-INF/resources/
- classpath:/resources/
- classpath:/static/
- classpath:/public
只要静态资源放在这些目录中的任何一个,SpringMVC都会帮我们处理。我们习惯会把静态资源放在classpath:/static/目录下。在resources目录下创建index.html文件。
打开浏览器输入 : http://localhost:8080/index.html
如果想要修改默认的静态资源路径,需要在application.yml中添加
spring: resources: static-locations: classpath:/webapp/ 复制代码
重新安装启动后生效。
3.自定义的拦截器
web开发中的拦截器也是我们经常需要使用的组件,可以帮我们完成一些日志记录,数据过滤,请求过滤等等很多功能,那么在SpringBoot中该怎么配置?
在SpringMVC中配置拦截器的步骤:
-
编写一个拦截器(需要实现HandlerInterceptor接口)
-
注册拦截器(xml配置mvc:interceptors)
ml <!--配置拦截器--> <mvc:interceptors> <mvc:interceptor> <!--配置拦截路径--> <mvc:mapping path="/user/**"/> <!--配置不拦截路径:不拦截路径是指从拦截路径中排除--> <mvc:exclude-mapping path="/user/sayByby"></mvc:exclude-mapping> <!--配置拦截器bean--> <bean class="com.dyy.interceptor.LogInterceptor2"></bean> </mvc:interceptor> </mvc:interceptors> 复制代码
因为Spring Boot没有XML配置文件了,所以在SpringBoot中使用拦截器注册的方式就不太一样了,需要借助一个WebMvcConfigurer类帮助我们注册拦截器,实现拦截器的具体步骤如下:
- 编写一个拦截器(实现HandlerInterceptor接口)
- 通过WebMvcConfigurer注册拦截器(自定义类是实现WebMvcConfigurer接口中
public void addInterceptors(InterceptorRegistry registry)
方法)
具体步骤如下
1.编写拦截器
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Component
public class MyInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("MyInterceptor拦截器的preHandle方法执行....");
return false;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("MyInterceptor拦截器的postHandle方法执行....");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("MyInterceptor拦截器的afterCompletion方法执行....");
}
}
复制代码
2.注册拦截器
import com.dyy.interceptor.MyInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class MvcConfig implements WebMvcConfigurer {
@Autowired
private MyInterceptor myInterceptor ;
/**
* /** 拦截当前目录及子目录下的所有路径 /user/** /user/findAll /user/order/findAll
* /* 拦截当前目录下的以及子路径 /user/* /user/findAll
* @param registry
*/
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(myInterceptor).addPathPatterns("/**");
}
}
复制代码
打开浏览器输入 http://localhost:8888/user/findAll
观察控制台。
4.整合Spring Data JPA
1.新建项目 springboot_jpa
2.添加Spring Data JPA的起步依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.2.RELEASE</version>
<relativePath/>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!-- springBoot JPA的起步依赖 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<!-- MySQL连接驱动 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- 配置使用redis启动器 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
</dependencies>
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3.在application.yml中配置数据库和jpa的相关属性
logging:
level:
com.dyy.dao: debug # 配置日志
spring:
datasource:
username: root
password: 123456
url: jdbc:mysql://127.0.0.1:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai
driver-class-name: com.mysql.cj.jdbc.Driver
jpa:
database: mysql
show-sql: true
generate-ddl: true
hibernate:
ddl-auto: update
naming_strategy: org.hibernate.cfg.ImprovedNamingStrategy
server:
port: 18081
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注意:Mysql8.x版本,连接时url需要指定时区,并且驱动类包名发生了变化。
4.创建实体类配置属性
import javax.persistence.*;
@Entity
@Table(name = "user")
public class User{
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Long id;
@Column(name = "username")
private String username;
@Column(name = "password")
private String password;
@Column(name = "name")
private String name;
//此处省略setter和getter方法... ...
}
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5.编写UserRepository
import com.dyy.domain.User;
import org.springframework.data.jpa.repository.JpaRepository;
public interface UserDao extends JpaRepository<User,Integer> {
}
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6.编写service类
import com.dyy.domain.User;
import java.util.List;
public interface UserService {
List<User> findUsers();
User findUserById(Integer id);
void saveUser(User user);
void updateUser(User user);
void deleteUserById(Integer id);
}
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7.service实现类
import com.dyy.dao.UserDao;
import com.dyy.domain.User;
import com.dyy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserDao userDao;
/**
* 查询所有
* @return
*/
@Override
public List<User> findUsers() {
return userDao.findAll();
}
/**
* 根据id查询
* @return
*/
@Override
public User findUserById(Integer id) {
return userDao.findById(id).get();
}
/**
* 保存
* @return
*/
@Override
public void saveUser(User user) {
userDao.save(user);
}
/**
* 更新
* @return
*/
@Override
public void updateUser(User user) {
userDao.save(user);
}
/**
* 根据id删除
* @return
*/
@Override
public void deleteUserById(Integer id) {
userDao.deleteById(id);
}
}
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8.编写Controller类
import com.dyy.domain.User;
import com.dyy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
@RequestMapping("/user")
public class UserController {
@Autowired
private UserService userService;
@RequestMapping("/findAll")
public List<User> findAll(){
return userService.findUsers();
}
}
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六、SpringBoot应用
1.环境搭建
1.数据库准备
create database springboot character set utf8 ;
use springboot ;
CREATE TABLE `tb_user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(20) NOT NULL,
`gender` varchar(5) DEFAULT NULL,
`age` int(11) DEFAULT NULL,
`address` varchar(32) DEFAULT NULL,
`qq` varchar(20) DEFAULT NULL,
`email` varchar(50) DEFAULT NULL,
`username` varchar(20) NOT NULL,
`phone` varchar(11) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `user_username_uindex` (`username`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8;
INSERT INTO `tb_user` VALUES (1,'黄蓉','女',38,'桃花岛','212223390222','[email protected]','huangrong','15600003333'),(2,'黄老邪','男',58,'湖北省武汉市','212223390','[email protected]','huanglaoxie','15872320405'),(3,'小龙女','男',18,'湖北省荆门市','212223390','[email protected]','xiaolongnv','15600004444'),(7,'杨过','男',30,'扬州','212223390','[email protected]','yangguo','15600005555');
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2.创建项目以及包结构
创建项目springboot_case
3.导入依赖
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.2.RELEASE</version>
</parent>
<dependencies>
<!--单元测试启动器-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
<!--通用mapper启动器依赖-->
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper-spring-boot-starter</artifactId>
<version>2.1.5</version>
</dependency>
<!--JDBC启动器依赖-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<!--mysql驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
<!--druid启动器依赖-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.10</version>
</dependency>
<!--web启动器依赖-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--spring boot actuator依赖-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!--编码工具包-->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
</dependency>
<!—热部署 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
</dependencies>
<build>
<plugins>
<!--spring boot maven插件 , 可以将项目运行依赖的jar包打到我们的项目中-->
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
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4.创建启动类
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import tk.mybatis.spring.annotation.MapperScan;
@SpringBootApplication
@MapperScan(basePackages = "com.dyy.dao")
@EnableTransactionManagement
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class,args);
}
}
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2.数据访问层
1.编写配置文件application.yml
server:
port: 10001
spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql:///springboot
username: root
password: root
type: com.alibaba.druid.pool.DruidDataSource
mybatis:
type-aliases-package: com.dyy.pojo
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2.编写实体类User
import java.io.Serializable;
@Entity
@Table(name = "tb_user")
public class User implements Serializable {
private Integer id;
private String name;
private String gender;
private Integer age;
private String address;
private String qq;
private String email;
private String username;
private String phone;
//getter setter toString…
}
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3.mapper接口和映射配置
import tk.mybatis.mapper.common.Mapper;
import java.util.List;
public interface UserMapper extends Mapper<User> {
}
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4.编写测试代码
@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMapperTest {
@Autowired
private UserMapper userMapper ;
@Test
public void findAll() {
List<User> users = userMapper.selectAll();
System.out.println(users);
}
}
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3.业务层
1.编写接口
public interface UserService {
/**
* 查询所有用户信息
* @return
*/
public List<User> findAll();
}
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2.编写实现类
import com.dyy.dao.UserMapper;
import com.dyy.pojo.User;
import com.dyy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper userMapper;
@Override
@Transactional(readOnly = true ,propagation = Propagation.SUPPORTS)
public List<User> findAll() {
return userMapper.selectAll();
}
}
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3.编写测试代码
@RunWith(SpringRunner.class)
@SpringBootTest
public class UserServiceTest {
@Autowired
private UserService userService;
@Test
public void findAll() {
List<User> users = userService.findAll();
System.out.println(users);
}
}
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注
Spring Boot整合单元测试,需要在测试类上添加两个注解:
- @RunWith(SpringRunner.class)指定Junit核心运行类
- @SpringBootTest指定这是一个Spring Boot的测试类,运行时会自动加载Spring Boot运行环境
4.表现层
1.引入依赖
<!--Web起步依赖-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--编码工具包-->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
</dependency>
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2.新建工具类
import java.io.Serializable;
public class Result implements Serializable {
private boolean status ; //响应状态 true false
private String msg ; // 响应信息
private Object data ; //处理成功的响应数据
public static Result ok(Object data){
Result result = new Result();
result.setStatus(true);
result.setData(data);
return result ;
}
public static Result error(String msg){
Result result = new Result();
result.setStatus(false);
result.setMsg(msg);
return result ;
}
// 生成set get tostring方法
}
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3.编写表现层代码
@Controller
@RequestMapping(path = "/user")
public class UserController {
@Autowired
private UserService userService;
/**
* 查询所有用户信息
* @return
*/
@RequestMapping(path = "/findAll")
@ResponseBody
public Result findAll() {
List<User> users = userService.findAll();
return Result.ok(users);
}
}
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4.代码测试
使用postman进行测试
5.页面展示
在resources
目录下创建static
目录 , 创建页面展示、list.html:
- 页面异步请求的端口和服务器端口一致
- 页面异步请求访问的路径和对应的表现层控制方法路径要致
- 页面异步请求参数名称和和对应的表现层控制方法参数一致
修改之后, 访问页面即可 : localhost:10001/list.html
6.缓存优化
1.缓存需求
问题:用户数据是不经常变化的数据,如果这些数据每次都去数据库中进行查询,效率比较低,对数据库造成很大的压力。
解决:缓存,用户第一次查询数据的时候,京数据存入到缓存中,之后再查询数据直接从缓存中获取即可,不需要再查询数据库。【此处使用redis缓存数据库存储数据】
2.依赖
<!--springboot整合redis启动器-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
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3.编写配置文件
spring:
redis: # 配置redis
host: localhost
port: 6379
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4.修改业务层实现类代码
import com.dyy.mapper.UserMapper;
import com.dyy.pojo.User;
import com.dyy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper userMapper ;
@Autowired
private RedisTemplate redisTemplate ;
@Override
@Transactional(readOnly = true ,propagation = Propagation.SUPPORTS)
public List<User> findAll() {
//从缓存中查询数据 规定存储用户信息使用string类型进行存储, 存储的key就是userList
List<User> userList = (List<User>) redisTemplate.boundValueOps("userList").get();
//如果缓存中没有数据, 查询数据库 , 将查询到的数据放入缓存
if(userList==null){
userList = userMapper.findAll();
redisTemplate.boundValueOps("userList").set(userList);
System.out.println("从数据库中查询...");
}else {
System.out.println("从缓存中查询.....");
}
//如果缓存中有数据, 直接返回
return userList ;
}
}
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七、SpringBoot其他组件
1.SpringBoot Actuator组件
作用
Spring Boot Actuator是SpringBoot自带的一个组件 , 可以帮助我们监控和管理Spring Boot应用,比如健康检查、审计、统计和HTTP追踪等。
如何使用
1.引入SpringBoot Actuator起步依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
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2.配置SpringBoot Actuator参数
management:
endpoints:
web:
exposure:
include: '*' # 对外暴露的访问入口 , 默认是/health和/info
base-path: /monitor # 默认是actuator
endpoint:
health:
show-details: ALWAYS # 显示所有健康状态
server:
port: 9999
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3.启动项目获取系统信息
目启动之后就可以通过发送http请求获取系统健康数据了 , 例如 : http://localhost:9999/monitor/health
, 返回数据如下 :
{
"status": "UP",
"details": {
"db": {
"status": "UP",
"details": {
"database": "MySQL",
"hello": 1
}
},
"diskSpace": {
"status": "UP",
"details": {
"total": 355816562688,
"free": 129251151872,
"threshold": 10485760
}
},
"redis": {
"status": "UP",
"details": {
"version": "2.8.9"
}
}
}
}
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常用的访问路径
HTTP 方法 | 路径 | 描述 |
---|---|---|
GET | /autoconfig | 提供了一份自动配置报告,记录哪些自动配置条件通过了,哪些没通过 |
GET | /configprops | 描述配置属性(包含默认值)如何注入Bean |
GET | /beans | 描述应用程序上下文里全部的Bean,以及它们的关系 |
GET | /dump | 获取线程活动的快照 |
GET | /env | 获取全部环境属性 |
GET | /env/{name} | 根据名称获取特定的环境属性值 |
GET | /health | 报告应用程序的健康指标,这些值由HealthIndicator的实现类提供 |
GET | /info | 获取应用程序的定制信息,这些信息由info打头的属性提供 |
GET | /mappings | 描述全部的URI路径,以及它们和控制器(包含Actuator端点)的映射关系 |
GET | /metrics | 报告各种应用程序度量信息,比如内存用量和HTTP请求计数 |
GET | /metrics/{name} | 报告指定名称的应用程序度量值 |
POST | /shutdown | 关闭应用程序,要求endpoints.shutdown.enabled设置为true |
GET | /trace | 提供基本的HTTP请求跟踪信息(时间戳、HTTP头等) |
我们可以通过发送这些请求,获取系统状态信息。
2.SpringBoot Admin组件
上面我们讲了Spring Boot Actuator
, 可以通过http协议获取系统状态信息 , 但是返回的是JSON格式数据, 看起来不太方面, 而且还需要记忆路径, 比较麻烦 , Spring Boot Admin
给我们提供了更加友好的可视化界面来查看这些信息 !
Spring Boot Admin是一个开源社区项目,用于管理和监控SpringBoot应用程序。 应用程序作为Spring Boot Admin Client
向Spring Boot Admin Server
注册 , Client
会定时向Server
发送数据, Server
使用友好的界面展示数据。
1.SpringBoot Admin服务端
1.创建项目springboot-admin-server
2.依赖
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.2.RELEASE</version>
</parent>
<groupId>com.dyy</groupId>
<artifactId>springboot-admin-server</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-server</artifactId>
<version>2.2.0</version>
</dependency>
</dependencies>
</project>
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3.配置application.yml
spring:
application:
name: admin-server
server:
port: 8769
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我们将Spring Boot Admin端口号设置为8769.
4.启动类
@SpringBootApplication
@EnableAdminServer
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class,args);
}
}
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@EnableAdminServer的作用是开启管理服务。
2.SpringBoot Admin客户端
1.创建springboot-admin-client
2.依赖
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-client</artifactId>
<version>2.2.0</version>
</dependency>
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3.配置
向admin-server注册的地址为http://localhost:8769,最后暴漏自己的actuator所有的端口信息,具体配置如下:
server:
port: 9999
spring:
application:
name: admin-client
boot:
admin:
client:
url: http://localhost:8769 # 指定注册地址 , Spring Boot Admin Server地址
management:
endpoints:
web:
exposure:
include: '*'
endpoint:
health:
show-details: ALWAYS
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这个注册的地址一定要和SpringBoot Admin Server地址匹配。
4.启动测试
分别开启客户端(应用程序)和服务端,访问http://localhost:8769,可以看到这样一个界面。
八、Spring Boot项目打包部署
1.项目打包
1.在pom中配置Spring Boot 项目的maven插件
<build>
<plugins>
<!-- 打jar包时如果不配置该插件,打出来的jar包没有清单文件 -->
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
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2.运行maven的打包命令
3.打包之前我们需要跳过测试
如果不跳过测试,那么我们编写的测试类都会被maven自动执行,可能会出现错误,导致打包不成功。
4.执行之后可以在控制台看到打包的日志信息,其中有生成的包的位置
打开指定目录就可以发现有一个jar包存在 , 仔细观察其实我们会发现 , 在target目录下其实会存在二个jar包 , 一个是springboot_02-1.0-SNAPSHOT.jar
一个是springboot_02-1.0-SNAPSHOT.jar.original
, 那么这两个jar包有什么区别呢?
我们如果是普通项目打包那么就只会得到一个jar包 , 这个jar包中不包含项目的一些依赖jar包
但是我们现在是一个Spring Boot项目 , 我们希望打完的包能够直接运行, 所以项目中就必须包含他的依赖jar包 , 我们之前在pom.xml
中配置一个Spring Boot的maven插件可以在普通包的基础上将我们项目的一些运行及依赖信息打进jar包里面 , 打完包之后将原来的普通包改名为xxx.jar.original
, 新打的包为xxx.jar
.
也就是说
.jar.original
是普通jar包,不包含依赖.jar
是可执行jar包,包含了pom中的所有依赖,可以直接用java -jar
命令执行- 如果是部署,就用
.jar
, 如果是给别的项目用,就要给.jar.original
这个包
2.项目运行
打开命令行运行打出来的包:使用命令:java -jar包全名
java -jar springboot_02-1.0-SNAPSHOT.jar
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