结合代码了解springMVC原理

创建一个maven项目。
在pom文件中配置用到的jar包

<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>springMVCdemo</groupId>  <artifactId>springMVC</artifactId>  <packaging>war</packaging>  <version>0.0.1-SNAPSHOT</version>  <name>springMVC Maven Webapp</name>  <url>http://maven.apache.org</url>  <dependencies>    <dependency>      <groupId>junit</groupId>      <artifactId>junit</artifactId>      <version>3.8.1</version>      <scope>test</scope>    </dependency>    <dependency>        <groupId>org.springframework</groupId>        <artifactId>spring-webmvc</artifactId>        <version>4.0.5.RELEASE</version>    </dependency>    <dependency>        <groupId>org.springframework</groupId>        <artifactId>spring-tx</artifactId>        <version>4.0.5.RELEASE</version>    </dependency>  </dependencies>  <build>    <finalName>springMVC</finalName>  </build></project>

1、在web.xml中配置ContextLoaderListener、applicationContext.xml、DispatcherServlet。

<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"           xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">  <display-name>Archetype Created Web Application</display-name>  <listener>        <listener-class>            org.springframework.web.context.ContextLoaderListener        </listener-class>  </listener>  <!-- 指定Spring Bean的配置文件所在目录。默认配置在WEB-INF目录下 -->    <context-param>        <param-name>contextConfigLocation</param-name>        <param-value>/WEB-INF/applicationContext.xml</param-value>    </context-param>  <servlet>        <servlet-name>spring</servlet-name>        <servlet-class>            org.springframework.web.servlet.DispatcherServlet        </servlet-class>        <init-param>            <param-name>contextConfigLocation</param-name>            <param-value>/WEB-INF/spring-mvc.xml</param-value>        </init-param>        <!-- 使系统在启动时装在servlet而不是第一个servlet被访问 -->        <load-on-startup>1</load-on-startup>    </servlet>    <servlet-mapping>        <servlet-name>spring</servlet-name>        <url-pattern>*.html</url-pattern>    </servlet-mapping></web-app>

2、在WEB-INF下创建spring-servlet.xml配置文件，这里我把文件名改成了spring-mvc.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:p="http://www.springframework.org/schema/p"             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/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd          http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">    <context:component-scan base-package="com.xjq"></context:component-scan></beans>

3、在WEB-INF下创建applicationContext.xml配置文件。因为这里只做一个springMVC的简单demo，涉及到数据源的配置文件都注释掉。

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"      xmlns:tx="http://www.springframework.org/schema/tx" xmlns:p="http://www.springframework.org/schema/p" xmlns:util="http://www.springframework.org/schema/util" xmlns:jdbc="http://www.springframework.org/schema/jdbc"      xmlns:cache="http://www.springframework.org/schema/cache"      xsi:schemaLocation="      http://www.springframework.org/schema/context      http://www.springframework.org/schema/context/spring-context.xsd      http://www.springframework.org/schema/beans      http://www.springframework.org/schema/beans/spring-beans.xsd      http://www.springframework.org/schema/tx      http://www.springframework.org/schema/tx/spring-tx.xsd      http://www.springframework.org/schema/jdbc      http://www.springframework.org/schema/jdbc/spring-jdbc-3.1.xsd      http://www.springframework.org/schema/cache      http://www.springframework.org/schema/cache/spring-cache-3.1.xsd      http://www.springframework.org/schema/aop      http://www.springframework.org/schema/aop/spring-aop.xsd      http://www.springframework.org/schema/util      http://www.springframework.org/schema/util/spring-util.xsd">      <!-- 自动扫描web包 ,将带有注解的类 纳入spring容器管理 -->      <context:component-scan base-package="com.xjq"></context:component-scan>     <!-- 引入jdbc配置文件 -->  <!--     <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">   --><!--         <property name="locations">   --><!--             <list>   --><!--                 <value>classpath*:jdbc.properties</value>   --><!--             </list>   --><!--         </property>   --><!--     </bean>   -->    <!-- dataSource 配置 -->  <!--     <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">   --><!--         基本属性 url、user、password   --><!--         <property name="url" value="${jdbc.url}" />   --><!--         <property name="username" value="${jdbc.username}" />   --><!--         <property name="password" value="${jdbc.password}" />   --><!--         配置初始化大小、最小、最大   --><!--         <property name="initialSize" value="1" />   --><!--         <property name="minIdle" value="1" />   --><!--         <property name="maxActive" value="20" />   --><!--         配置获取连接等待超时的时间   --><!--         <property name="maxWait" value="60000" />   --><!--         配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒   --><!--         <property name="timeBetweenEvictionRunsMillis" value="60000" />   --><!--         配置一个连接在池中最小生存的时间，单位是毫秒   --><!--         <property name="minEvictableIdleTimeMillis" value="300000" />   --><!--         <property name="validationQuery" value="SELECT 'x'" />   --><!--         <property name="testWhileIdle" value="true" />   --><!--         <property name="testOnBorrow" value="false" />   --><!--         <property name="testOnReturn" value="false" />   --><!--         打开PSCache，并且指定每个连接上PSCache的大小   --><!--         <property name="poolPreparedStatements" value="false" />   --><!--         <property name="maxPoolPreparedStatementPerConnectionSize" value="20" />   --><!--         配置监控统计拦截的filters   --><!--         <property name="filters" value="stat" />   --><!--     </bean>   -->    <!-- mybatis文件配置，扫描所有mapper文件 -->  <!--     <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean" p:dataSource-ref="dataSource" p:configLocation="classpath:mybatis-config.xml" p:mapperLocations="classpath:com/eduoinfo/finances/bank/web/dao/*.xml" />   -->    <!-- spring与mybatis整合配置，扫描所有dao -->  <!--     <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer" p:basePackage="com.eduoinfo.finances.bank.web.dao" p:sqlSessionFactoryBeanName="sqlSessionFactory" />   -->    <!-- 对dataSource 数据源进行事务管理 -->  <!--     <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager" p:dataSource-ref="dataSource" />   -->    <!-- 配置使Spring采用CGLIB代理 -->  <!--     <aop:aspectj-autoproxy proxy-target-class="true" />   -->    <!-- 启用对事务注解的支持 -->  <!--     <tx:annotation-driven transaction-manager="transactionManager" />   -->    <!-- Cache配置 -->  <!--     <cache:annotation-driven cache-manager="cacheManager" />   --><!--     <bean id="ehCacheManagerFactory" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean" p:configLocation="classpath:ehcache.xml" />   --><!--     <bean id="cacheManager" class="org.springframework.cache.ehcache.EhCacheCacheManager" p:cacheManager-ref="ehCacheManagerFactory" />   --></beans>  

4、在WEB-INF下创建jsp文件夹，在文件夹中创建login.jsp和success.jsp。
login.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>登陆</title></head><body>    <form action="login.html">        <p>            用户名：<input name="uname" type="text">        </p>        <p>            密&nbsp;&nbsp;码：<input name="psw" type="password">        </p>        <p>            <input name="submit" type="submit">        </p>    </form>    <font color="red">${error}</font></body></html>

success.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>登陆成功</title></head><body>    <h1 >登陆成功</h1></body></html>

5、创建controller和service的java类。
controller.java:

package com.xjq.springmvc.controller;import javax.annotation.Resource;import javax.servlet.http.HttpServletRequest;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.servlet.ModelAndView;import com.xjq.springmvc.service.LoginService;@Controllerpublic class LoginController {    // 登陆页面url    public static final String loginUrl = "WEB-INF/jsp/login.jsp";    // homePage url    public static final String homeUrl = "WEB-INF/jsp/success.jsp";    @Resource    LoginService service;    @Resource    HttpServletRequest request;    @RequestMapping("spring")    public ModelAndView toLoginPage(){        return new ModelAndView(loginUrl);    }    @RequestMapping("login")    public ModelAndView doLogin(){        String username = request.getParameter("uname");        String pwd = request.getParameter("psw");        return service.doLogin(loginUrl, homeUrl, username, pwd);    }}

service.java:

package com.xjq.springmvc.service;import org.springframework.stereotype.Service;import org.springframework.web.servlet.ModelAndView;@Servicepublic class LoginService {    public ModelAndView doLogin(String loginUrl, String homeUrl, String username, String pwd){        if(username == null || "".equals(username)){            return new ModelAndView(loginUrl, "error", "用户名不能为空！");        }        if(pwd == null || "".equals(pwd)){            return new ModelAndView(loginUrl, "error", "密码不能为空！");        }        if(!"admin".equals(username) || !"123".equals(pwd)){            return new ModelAndView(loginUrl, "error", "用户名或密码不正确！");        }        return new ModelAndView(homeUrl);    }}

至此，代码和配置结束，运行tomcat。