Spring Boot 系列 —— Hello World

其他 2018-10-30 19:31:56 阅读次数: 0
版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/lewis_007/article/details/50901049

在这个章节，先来一个Hello World的Web应用，用以对Spring Boot做一个初步的了解。

我打算使用Maven和Eclipse开始我们的Hello World。

准备

Spring Boot当前最新版本为1.3.3.RELEASE，按照官方文档指引，首先确保安装了JDK 1.6+、Maven 3.2+。

以Windows为例，在命令行输入命令，如下：

C:\Users\lewis>java -version
java version "1.8.0_74"
Java(TM) SE Runtime Environment (build 1.8.0_74-b02)
Java HotSpot(TM) 64-Bit Server VM (build 25.74-b02, mixed mode)
C:\Users\lewis>mvn --v
Apache Maven 3.3.9 (bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-11T00:41:47+08:00)
Maven home: D:\Apps\DevpApp\Apache\apache-maven-3.3.9
Java version: 1.8.0_74, vendor: Oracle Corporation
Java home: D:\Apps\DevpApp\Java\jdk1.8.0_74\jre
Default locale: zh_CN, platform encoding: GBK
OS name: "windows 10", version: "10.0", arch: "amd64", family: "dos"

创建Maven Project

首先通过Eclipse创建一个Maven Project，其pom文件如下：

<?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>

    <groupId>org.learn.springboot</groupId>
    <artifactId>gs-spring-boot</artifactId>
    <version>0.1.0</version>

</project>

添加spring-boot-starter-parent

Spring Boot提供了一系列starter POMs，这个在前一篇文章有介绍。其中spring-boot-starter-parent是一个特殊的starter，它提供了很多有用的Maven默认设置，重要的是它还包括一个dependency-management。

在pom文件中加入如下代码：

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.3.RELEASE</version>
    </parent>

添加依赖

既然是Web应用，那么为我们的项目添加spring-boot-starter-web依赖。

在pom文件中加入如下代码：

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

编写代码

为完成Hello World的Web应用，我们需要一个Java文件。

在src/main/java目录下，创建一个类SampleController，代码如下：

package org.learn.springboot.gs;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@EnableAutoConfiguration
public class SampleController {

    @RequestMapping("/")
    @ResponseBody
    String home() {
        return "Hello World!";
    }

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SampleController.class, args);
    }
}

运行

到这里，所有工作就完成了，剩下就是运行看效果了。

在Eclipse中启动你的SampleController类，控制台会输出信息：

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.3.3.RELEASE)

2016-03-15 22:58:41.200  INFO 2636 --- [           main] o.learn.springboot.gs.SampleController   : Starting SampleController on DESKTOP-RSSEC8O with PID 2636 (E:\work\project\learn-spring-boot\gs-spring-boot\target\classes started by lewis in E:\work\project\learn-spring-boot\gs-spring-boot)
2016-03-15 22:58:41.216  INFO 2636 --- [           main] o.learn.springboot.gs.SampleController   : No active profile set, falling back to default profiles: default
2016-03-15 22:58:41.341  INFO 2636 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@df27fae: startup date [Tue Mar 15 22:58:41 CST 2016]; root of context hierarchy
2016-03-15 22:58:42.403  INFO 2636 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Overriding bean definition for bean 'beanNameViewResolver' with a different definition: replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class]]
2016-03-15 22:58:43.636  INFO 2636 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2016-03-15 22:58:43.677  INFO 2636 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2016-03-15 22:58:43.677  INFO 2636 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.0.32
2016-03-15 22:58:43.896  INFO 2636 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2016-03-15 22:58:43.896  INFO 2636 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 2586 ms
2016-03-15 22:58:44.318  INFO 2636 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]
2016-03-15 22:58:44.318  INFO 2636 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'characterEncodingFilter' to: [/*]
2016-03-15 22:58:44.318  INFO 2636 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2016-03-15 22:58:44.318  INFO 2636 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2016-03-15 22:58:44.318  INFO 2636 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'requestContextFilter' to: [/*]
2016-03-15 22:58:44.728  INFO 2636 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@df27fae: startup date [Tue Mar 15 22:58:41 CST 2016]; root of context hierarchy
2016-03-15 22:58:44.838  INFO 2636 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto java.lang.String org.learn.springboot.gs.SampleController.home()
2016-03-15 22:58:44.854  INFO 2636 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2016-03-15 22:58:44.854  INFO 2636 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2016-03-15 22:58:44.947  INFO 2636 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-03-15 22:58:44.947  INFO 2636 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-03-15 22:58:45.026  INFO 2636 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-03-15 22:58:45.244  INFO 2636 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2016-03-15 22:58:45.401  INFO 2636 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2016-03-15 22:58:45.416  INFO 2636 --- [           main] o.learn.springboot.gs.SampleController   : Started SampleController in 5.17 seconds (JVM running for 6.246)

在浏览器中打开localhost:8080，页面会带给你惊喜：

Hello World!

创建可执行的jar包

再一次惊喜，把这些变成一个可执行的jar包，并且发布生产环境可独立运行。

在pom文件中加入如下代码：

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

然后，在命令行执行mvn package：

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building gs-spring-boot 0.1.0
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- ------
[INFO] 
[INFO] --- maven-jar-plugin:2.5:jar (default-jar) @ gs-spring-boot ---
[INFO] Building jar: E:\work\project\learn-spring-boot\gs-spring-boot\target\gs-spring-boot-0.1.0.jar
[INFO] 
[INFO] --- spring-boot-maven-plugin:1.3.3.RELEASE:repackage (default) @ gs-spring-boot ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

在工程的target目录下，你会看到gs-spring-boot-0.1.0.jar，大概12.8M，因为这个jar包包含了所有的依赖lib。

通过压缩软件或者在命令行输入命令java tvf gs-spring-boot-0.1.0.jar，你可以进一步研究下这个jar包的内部结构。

在命令行，进入target目录，输入命令java -jar，如下：

E:\work\project\learn-spring-boot\gs-spring-boot\target>java -jar gs-spring-boot-0.1.0.jar

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.3.3.RELEASE)

2016-03-15 23:20:47.934  INFO 5252 --- [           main] o.learn.springboot.gs.SampleController   : Starting SampleController v0.1.0 on DESKTOP-RSSEC8O with PID 5252 (E:\work\project\learn-spring-boot\gs-spring-boot\target\gs-spring-boot-0.1.0.jar started by lewis in E:\work\project\learn-spring-boot\gs-spring-boot\target)
2016-03-15 23:20:47.934  INFO 5252 --- [           main] o.learn.springboot.gs.SampleController   : No active profile set, falling back to default profiles: default
2016-03-15 23:20:47.996  INFO 5252 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@29159081: startup date [Tue Mar 15 23:20:47 CST 2016]; root of context hierarchy
......
2016-03-15 23:20:52.082  INFO 5252 --- [           main] o.learn.springboot.gs.SampleController   : Started SampleController in 4.679 seconds (JVM running for 5.326)

在浏览器中打开localhost:8080，页面会再一次带给你惊喜。

猜你喜欢

转载自blog.csdn.net/lewis_007/article/details/50901049
今日推荐
面壁智能发布 Eurux-8x22B 开源大模型 —— 堪称「理科状元」
开源日报 | 谷歌扶持鸿蒙上位；开源Rabbit R1；Docker加持的安卓手机；微软的焦虑和野心；海尔电器把开放平台关了
中国码农的“35岁魔咒”
蘭雅 CorelDRAW 插件 2024.5.1 国际劳动节版，免费下载
Arc Browser for Windows 1.0 正式 GA
90后程序员开发视频搬运软件、不到一年获利超 700 万，结局很刑！
周排行
【转】spring中对控制反转和依赖注入的理解
tms webcore 安装和使用
java程序员进阶相关书籍
SpringMVC接受请求参数、
如何保存训练好的机器学习模型
MyEclipse、Eclipse设置项目JDK的三个地方
商超行业微信小程序开发定制一般多少钱 （行业技术人员解读）
Markdown编辑器语言——30分钟入门到到精通
Linux系统下MongoDB的简单安装与基本操作
Power Strings
每日归档
更多
2024-05-07(14)
2024-05-06(40)
2024-05-05(0)
2024-05-04(7)
2024-05-03(19)
2024-05-02(0)
2024-05-01(4)
2024-04-30(1)
2024-04-29(40)
2024-04-28(0)

代码天地 © 2018 codetd.com

境外服务器   最新电视剧2022