SpringMVC最近大有赶超struts2的趋势。
乘着在学校有空对该框架做一定的熟悉和了解,争取毕业设计用这个框架完成
第一部建立一个web项目
maven构建语句,构建出一个空的web项目
mvn archetype:create -DgroupId=packageName -DartifactId=webappName -DarchetypeArtifactId=maven-archetype-webapp -Dwtpversion=1.0
接着在pom中加入spring MVC的依赖
<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/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.springframework.mvc</groupId> <artifactId>mvc</artifactId> <packaging>war</packaging> <version>1.0-SNAPSHOT</version> <name>mvc Maven Webapp</name> <url>http://maven.apache.org</url> <properties> <java-version>1.6</java-version> <org.springframework-version>3.1.0.RELEASE</org.springframework-version> <org.aspectj-version>1.6.10</org.aspectj-version> <org.slf4j-version>1.6.1</org.slf4j-version> </properties> <dependencies> <!-- Spring --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${org.springframework-version}</version> <exclusions> <!-- Exclude Commons Logging in favor of SLF4j --> <exclusion> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${org.springframework-version}</version> </dependency> <!-- AspectJ --> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>${org.aspectj-version}</version> </dependency> <!-- Logging --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>${org.slf4j-version}</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>jcl-over-slf4j</artifactId> <version>${org.slf4j-version}</version> <scope>runtime</scope> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>${org.slf4j-version}</version> <scope>runtime</scope> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.16</version> <scope>runtime</scope> </dependency> <!-- @Inject --> <dependency> <groupId>javax.inject</groupId> <artifactId>javax.inject</artifactId> <version>1</version> </dependency> <!-- Servlet --> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.5</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>2.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet.jsp.jstl</groupId> <artifactId>jstl-api</artifactId> <version>1.2</version> </dependency> <dependency> <groupId>org.glassfish.web</groupId> <artifactId>jstl-impl</artifactId> <version>1.2</version> </dependency> <!-- Jackson JSON Processor --> <dependency> <groupId>org.codehaus.jackson</groupId> <artifactId>jackson-mapper-asl</artifactId> <version>1.8.1</version> </dependency> <!-- Rome Atom+RSS --> <dependency> <groupId>net.java.dev.rome</groupId> <artifactId>rome</artifactId> <version>1.0.0</version> </dependency> <!-- JSR 303 with Hibernate Validator --> <dependency> <groupId>javax.validation</groupId> <artifactId>validation-api</artifactId> <version>1.0.0.GA</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-validator</artifactId> <version>4.1.0.Final</version> </dependency> <!-- Joda Time Library --> <dependency> <groupId>joda-time</groupId> <artifactId>joda-time</artifactId> <version>1.6.2</version> </dependency> <!-- File Upload --> <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.2.2</version> </dependency> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.0.1</version> </dependency> <!-- Test --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.8.2</version> <scope>test</scope> </dependency> </dependencies> <repositories> <!-- For testing against latest Spring snapshots --> <repository> <id>org.springframework.maven.snapshot</id> <name>Spring Maven Snapshot Repository</name> <url>http://maven.springframework.org/snapshot</url> <releases><enabled>false</enabled></releases> <snapshots><enabled>true</enabled></snapshots> </repository> <!-- For developing against latest Spring milestones --> <repository> <id>org.springframework.maven.milestone</id> <name>Spring Maven Milestone Repository</name> <url>http://maven.springframework.org/milestone</url> <snapshots><enabled>false</enabled></snapshots> </repository> </repositories> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>2.3.2</version> <configuration> <source>${java-version}</source> <target>${java-version}</target> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <executions> <execution> <id>install</id> <phase>install</phase> <goals> <goal>sources</goal> </goals> </execution> </executions> </plugin> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>aspectj-maven-plugin</artifactId> <!-- Have to use version 1.2 since version 1.3 does not appear to work with ITDs --> <version>1.2</version> <dependencies> <!-- You must use Maven 2.0.9 or above or these are ignored (see MNG-2972) --> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>${org.aspectj-version}</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjtools</artifactId> <version>${org.aspectj-version}</version> </dependency> </dependencies> <executions> <execution> <goals> <goal>compile</goal> <goal>test-compile</goal> </goals> </execution> </executions> <configuration> <outxml>true</outxml> <source>${java-version}</source> <target>${java-version}</target> </configuration> </plugin> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>tomcat-maven-plugin</artifactId> <version>1.1</version> </plugin> </plugins> </build> </project>
这样我们的依赖已经配置齐全了,接下来就是配置前端控制器FrontController在SpringMVC中是DispatcherServlet
他位于org.springframework.web.servlet.DispatcherServlet
在web.xml中配置
<!-- 处理所有请求 process all request --> <servlet> <servlet-name>FrontController</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> //会反射注入 <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/spring/appServlet/servlet-context.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>FrontController</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping>
我们看一下init-param为什么必须得叫做contextConfigLocation
首先看DispatcherServlet的构造方法
public DispatcherServlet() { super(); }
查看父类发现有setContextConfigLocation方法
/** * Set the context config location explicitly, instead of relying on the default * location built from the namespace. This location string can consist of * multiple locations separated by any number of commas and spaces. */ public void setContextConfigLocation(String contextConfigLocation) { this.contextConfigLocation = contextConfigLocation; }
查看是谁调用了这个方法
没人调用这个方法,那么假定这个方法是被反射调用的
再往父类上查找,可以在setContextConfigLocation处加一个断点,debug的时候就能看到是如何被调用的
/** * Map config parameters onto bean properties of this servlet, and * invoke subclass initialization. * @throws ServletException if bean properties are invalid (or required * properties are missing), or if subclass initialization fails. */ @Override public final void init() throws ServletException { if (logger.isDebugEnabled()) { logger.debug("Initializing servlet '" + getServletName() + "'"); } // Set bean properties from init parameters. try { //获得所有的属性值 PropertyValues pvs = new ServletConfigPropertyValues(getServletConfig(), this.requiredProperties); BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(this); ResourceLoader resourceLoader = new ServletContextResourceLoader(getServletContext()); bw.registerCustomEditor(Resource.class, new ResourceEditor(resourceLoader, this.environment)); initBeanWrapper(bw); bw.setPropertyValues(pvs, true); } catch (BeansException ex) { logger.error("Failed to set bean properties on servlet '" + getServletName() + "'", ex); throw ex; } // Let subclasses do whatever initialization they like. initServletBean(); if (logger.isDebugEnabled()) { logger.debug("Servlet '" + getServletName() + "' configured successfully"); } }
通过AbstractPropertyAccessor往里面填充属性
public void setPropertyValues(PropertyValues pvs, boolean ignoreUnknown, boolean ignoreInvalid) throws BeansException { List<PropertyAccessException> propertyAccessExceptions = null; List<PropertyValue> propertyValues = (pvs instanceof MutablePropertyValues ? ((MutablePropertyValues) pvs).getPropertyValueList() : Arrays.asList(pvs.getPropertyValues())); for (PropertyValue pv : propertyValues) { try { // This method may throw any BeansException, which won't be caught // here, if there is a critical failure such as no matching field. // We can attempt to deal only with less serious exceptions. //往里面填充属性的核心方法 setPropertyValue(pv); } catch (NotWritablePropertyException ex) { if (!ignoreUnknown) { throw ex; } // Otherwise, just ignore it and continue... } catch (NullValueInNestedPathException ex) { if (!ignoreInvalid) { throw ex; } // Otherwise, just ignore it and continue... } catch (PropertyAccessException ex) { if (propertyAccessExceptions == null) { propertyAccessExceptions = new LinkedList<PropertyAccessException>(); } propertyAccessExceptions.add(ex); } } // If we encountered individual exceptions, throw the composite exception. if (propertyAccessExceptions != null) { PropertyAccessException[] paeArray = propertyAccessExceptions.toArray(new PropertyAccessException[propertyAccessExceptions.size()]); throw new PropertyBatchUpdateException(paeArray); } }
可以看到在BeanWrapperImp当中实现了setPropertyValue(String propertyName, Object value)方法
public void setPropertyValue(String propertyName, Object value) throws BeansException {
BeanWrapperImpl nestedBw;
try {
nestedBw = getBeanWrapperForPropertyPath(propertyName);
}
catch (NotReadablePropertyException ex) {
throw new NotWritablePropertyException(getRootClass(), this.nestedPath + propertyName,
"Nested property in path '" + propertyName + "' does not exist", ex);
}
PropertyTokenHolder tokens = getPropertyNameTokens(getFinalPath(nestedBw, propertyName));
nestedBw.setPropertyValue(tokens, new PropertyValue(propertyName, value));
}
可以看到这里的确是反射调用的.
这样就完成了springMVC资源的载入
看下之前载入的资源文件做了什么
<?xml version="1.0" encoding="UTF-8"?> <beans:beans xmlns="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans" xsi:schemaLocation=" http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd"> <!-- 开启注解 --> <annotation-driven /> <!-- 引入用户定义的@Controller 用来处理请求 --> <beans:import resource="controllers.xml" /> </beans:beans>
再看一下controllers.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> <!-- 自动扫描组件 --> <context:component-scan base-package="com.springframework.helloworld" /> </beans>
包扫描把所有有@controller注解的类spring会对其进行加载
@Controller //注解表示自己是controller public class SimpleController { //对应映射的路径 这里就表示 http://localhost/项目名/simple会映射到该控制器 @RequestMapping("/simple") //@ResponseBody表示这个返回的string将会当成输出值返回给浏览器 public @ResponseBody String simple() { return "hello world!"; } }
所有的处理完毕~ 放入tomcat第一个springMVC的Helloworld就诞生啦~