SpringMVC 入门 -- Handler编写

本文仅作代码的记录

结构：



libaraies:



web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>SpringMVCTest</display-name>
<!-- Spring 前端控制器 -->
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!-- contextConfigLocation配置springMVC加载的配置文件（配置处理器、映射器、适配器等） -->
<!-- 默认加载/WEB-INF/SERVLET名称-servlet.xml(springmvc-servlet.xml) -->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<!-- 第一种 *.action 访问以action结尾的 -->
<!-- 第二种 / 所有地址都解析。所以要配置静态资源不进行解析。使用此中方法可以实现RESTful风格 -->
<!-- 第三种 /* 这样配置不对。使用这种配置最终要转发到jsp页面时，仍然会由DispatcherServlet解析jsp地址，不能根据jsp找到handler，会报错 -->

<url-pattern>*.action</url-pattern>

</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<filter>
<filter-name>myFilter</filter-name>
<filter-class>com.yrsoft.filter.MyFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>myFilter</filter-name>
<servlet-name>springmvc</servlet-name>
</filter-mapping>
</web-app>

springmvc.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 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 ">
<!--  配置handler-->
<bean name="/queryuser.action" class= "com.yrsoft.controller.ItemsController1"></bean>

<!--  处理器适配器
所有的处理器适配器都实现HandlerAdapter接口
-->
<bean class = "org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
<!--  处理器映射器
将bean的name当作url进行查找。需要在配置Handler时指定beanname（就是url）
-->
<bean class = "org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
<!--  视图解析器
解析jsp视图，默认使用jstl路径
-->
<bean class = "org.springframework.web.servlet.view.InternalResourceViewResolver"/>

</beans>

controller

package com.yrsoft.controller;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

import com.yrsoft.po.Users;

/**
* 实现Cintroller接口的处理器，一定要实现Controller接口
*
*/
public class ItemsController1 implements Controller{
@Override
public ModelAndView handleRequest(HttpServletRequest request,
HttpServletResponse response) throws Exception {
//调用service查找数据。查询用户列表。

List<Users> userList = new ArrayList<Users>();
//填充静态数据
Users user1 = new Users("admin","123");
Users user2 = new Users("123", "345");
userList.add(user1);
userList.add(user2);

//返回ModelAndView
ModelAndView modelAndView = new ModelAndView();
//相当于request的setAttribute，在jsp页面中通过userList后去数据
modelAndView.addObject("userList",userList);

//指定视图
modelAndView.setViewName("/WEB-INF/jsp/users/userList.jsp");

return modelAndView;
}

}

MyFilter

package com.yrsoft.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import com.yrsoft.po.Users;
/**一定要实现Filter接口*/
public class MyFilter implements Filter {
@Override
public void destroy() {
System.out.println("Destroy ");
}
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest servletRequest = (HttpServletRequest) request;
HttpSession session = servletRequest.getSession();
Users user = (Users) session.getAttribute("user");
if (user == null ) {
System.out.println("注入User ");
user = new Users("张三","123");
session.setAttribute("user", user);
request.getRequestDispatcher("/WEB-INF/jsp/users/userList.jsp").forward(request, response);
} else {
System.out.println(user.toString());
chain.doFilter(request, response);
}
//		chain.doFilter(request, response);
}
@Override
public void init(FilterConfig arg0) throws ServletException {
System.out.println("init");
}

}

chain.doFilter() 会再次进入这个filter执行doFilter，还没研究原因。