spring mvc示例_servlet获取spring Bean

示例代码

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" 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_2_5.xsd">  <display-name></display-name>   <!--  创建springmvc 需要一个xml文件和applicationContext.xml 这里要理解initparam的含义        mvc*.* 就是去寻找为mvc开头的文件,所有所创建的spring mvc的xml文件必须要有mvc开头        命名为:mvc-context.xml 并且按照context-param中的配置,将applicationContext文件        命名为:root-context.xml -->    <!-- 监听spring 上下文容器 -->  <listener>     <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>  </listener>  <!-- 加载spring 的xml配置文件到 spring的上下文容器中-->  <context-param>     <param-name>contextConfigLocation</param-name>     <!-- 这里指定的classpath 为项目编译后的classes目录 -->     <param-value>classpath:root-context.xml</param-value>  </context-param>    <!-- 首先在web.xml中配置一个DispatcherServlet -->  <!-- 核心类,spring mvc DispatcherServlet -->  <servlet>    <servlet-name>mvc</servlet-name>    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>    <init-param>       <param-name>contextConfigLocation</param-name>       <param-value>/WEB-INF/classes/mvc*.*</param-value>    </init-param>    <load-on-startup>1</load-on-startup>  </servlet>  <servlet>    <description>This is the description of my J2EE component</description>    <display-name>This is the display name of my J2EE component</display-name>    <servlet-name>UserAuthorizationFilter</servlet-name>    <servlet-class>com.qingyuan.controller.UserAuthorizationFilter</servlet-class>  </servlet>  <servlet-mapping>     <servlet-name>mvc</servlet-name>     <url-pattern>*.html</url-pattern>  </servlet-mapping>  <servlet-mapping>    <servlet-name>UserAuthorizationFilter</servlet-name>    <url-pattern>/servlet/auth</url-pattern>  </servlet-mapping>    <filter>       <filter-name>CharacterEncodingFilter</filter-name>       <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>       <init-param>           <param-name>encoding</param-name>           <param-value>utf-8</param-value>       </init-param>     </filter>     <filter-mapping>       <filter-name>CharacterEncodingFilter</filter-name>       <url-pattern>/*</url-pattern>     </filter-mapping>      <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app><?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"      xmlns:p="http://www.springframework.org/schema/p" xmlns:aop="http://www.springframework.org/schema/aop"      xmlns:context="http://www.springframework.org/schema/context"      xsi:schemaLocation="http://www.springframework.org/schema/mvc                 http://www.springframework.org/schema/mvc/spring-mvc.xsd                  http://www.springframework.org/schema/aop                  http://www.springframework.org/schema/aop/spring-aop-3.2.xsd                 http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd                  http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">         <!-- 首先通过import标签 导入root-context.xml,然后通过component-scan标签扫描指定包名，        让该包下的所有java类的spring注解生效然后配置SpringMVC的视图渲染解析器，        让其前缀为/page/ 后缀为.jsp 这样能够SpringMVC 所需要渲染的路径能够在/page/返回值.jsp中寻找 -->            <!-- 加载spring 的全局配置文件 -->   <beans:import resource="root-context.xml"/>             <!-- 通过component-scan 让spring扫描com.qingyuan.controller下的所有类        让spring 的代码注解生效 -->   <context:component-scan base-package="com.qingyuan.controller" />          <!-- 配置SpringMVC的视图渲染器， 让其前缀为:/ 后缀为.jsp  将视图渲染到/page/<method返回值>.jsp中 -->      <beans:bean          class="org.springframework.web.servlet.view.InternalResourceViewResolver"          p:prefix="/page/" p:suffix=".jsp">        </beans:bean></beans:beans><?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:context="http://www.springframework.org/schema/context"          xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd                      http://www.springframework.org/schema/context                       http://www.springframework.org/schema/context/spring-context-3.2.xsd                      http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">     <bean id="userController"class="com.qingyuan.controller.UserController"></bean>               </beans>     package com.qingyuan.controller;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.servlet.ModelAndView;/** *  使用注解@Controller 将HomeController 类定义为一个Controller,并且在方法中通过 *  @RequestMapping("value") 来指定所需要访问的路径或者方法名称,springmvc 可以 *  通过一个@controller注解将一个POJO转化为处理请求的控制器,通过@RequestMapping *  为控制器指定哪些需要的请求 */@Controllerpublic class HomeController {/** * 返回到 /page/home.jsp * 方法中定义了ModelAndView对象， * 通过该对象指定所需要渲染的视图为home最后返回ModelAndView  * 将页面渲染到home.jsp中 * @return */@RequestMapping("index")public ModelAndView index(){// 创建模型跟视图,用于渲染页面,并且指定要返回的页面为home页面ModelAndView mav = new ModelAndView("home");return mav;}}package com.qingyuan.controller;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.context.WebApplicationContext;import org.springframework.web.context.support.WebApplicationContextUtils;/** *  servlet 容器中获取spring 容器中的Bean */public class UserAuthorizationFilter extends HttpServlet {private WebApplicationContext wac;private static final long serialVersionUID = 2330673658987873853L;public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {            this.doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html;charset=gbk");// PrintWriter out = response.getWriter();// com.qingyuan.controller.UserController@163de4eUserController userController = (UserController)wac.getBean("userController");}@Overridepublic void init() throws ServletException {       wac =WebApplicationContextUtils.getRequiredWebApplicationContext(       this.getServletContext());       // wac = WebApplicationContextUtils.getWebApplicationContext(       // this.getServletContext());       // wac的类型：org.springframework.web.context.support.XmlWebApplicationContext               // super.init();}}package com.qingyuan.controller;import javax.servlet.http.HttpServletRequest;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.servlet.ModelAndView;// http://jinnianshilongnian.iteye.com/blog/1594806@Controllerpublic class UserController {@RequestMapping("login")public ModelAndView login(String username, String password){if (this.checkParams(new String[]{username, password})){ModelAndView mav = new ModelAndView("succ");mav.addObject("username", username);mav.addObject("password", password);return mav;}return new ModelAndView("home");}@RequestMapping(value="login2222",method=RequestMethod.POST)  public ModelAndView login(String username,String password,HttpServletRequest request){      request.setAttribute("username", username);      request.setAttribute("password", password);          return new ModelAndView("succ");  }  private boolean checkParams(String[] params) {   for (String param:params)   {              if (param == "" || param==null || param.isEmpty())            {                  return false;              }          }          return true;  }}http://docs.spring.io/spring/docs/3.1.x/spring-framework-reference/htmlsingle/spring-framework-reference.htmlhttp://docs.spring.io/spring/docs/4.0.9.RELEASE/spring-framework-reference/htmlsingle/http://projects.spring.io/spring-framework/SpringMVC框架是围绕DispatcherServlet这个核心展开,DispatcherServlet这个Servlet负责拦截请求,并将其分派给相应的处理类来处理SpringMVC是基于Model2实现的技术框架，Model2是经典的MVC模型在Web应用中的变体，这个改变主要源于HTTP协议的无状态性。Model2的目的和MVC一样，也是利用处理器分离模型(Model)、视图(View)和控制(Control)，达到不同技术层级间松散层耦合的效果，让系统更有灵活、复用性和可维护性.分析：1、 由最先的HTPP发送请求，由所配置的XML中的DispatcherServlet处理。2、 DispatcherServlet接受到这个请求后，根据请求的信息及HandlerMapping的配置找到处理请求的处理器Handler。3、 得到HandlerMapping对应的Handler后，通过HandlerAdapter对Handler进行封装，再以统一的适配器接口调用Handler。4、 处理器完成业务逻辑的处理后返回一个ModelAndView给DispatcherServlet。5、 ModelAndView包含逻辑视图名，而非真正的视图对象，DispatcherServlet借由ViewResolver完成逻辑视图名到真实视    图对象的解析工作。6、 当得到真实View对象后，DispatcherServlet就对这个View对象进行渲染7、 最终返回到客户的HTTP响应

参考博文" http://blog.csdn.net/swingpyzf/article/details/8885459