struts2学习笔记（一）

1.搭建第一个struts2 app.

web.xml

 <?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">

   <welcome-file-list>

     <welcome-file>index.jsp</welcome-file>

   </welcome-file-list>

   <filter>

         <filter-name>struts2</filter-name>

         <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>

     </filter>

     <filter-mapping>

         <filter-name>struts2</filter-name>

         <url-pattern>/*</url-pattern>

     </filter-mapping>

 </web-app>

注：struts1框架由servlet启动，strust2框架由filter启动

struts.xml

 <?xml version="1.0" encoding="UTF-8" ?>

 <!DOCTYPE struts PUBLIC

     "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"

     "http://struts.apache.org/dtds/struts-2.0.dtd">

 <struts>

     <!-- Add packages here -->

     <package name="alibaba" extends="struts-default" namespace="/alibaba">

        <action name="helloWorld" method="excute" class="com.alibaba.struts2.HelloWorld">

           <result name="success">/WEB-INF/page/helloWorld.jsp</result>

        </action>

     </package>

 </struts>

注：extends="struts-default"，是关键。使用struts2框架核心功能，比如说文件上传等。需要继承struts2-default 这个包

在struts-default.xml文件中可以看到

     <package name="struts-default" abstract="true">

     ....

      <interceptor name="alias" class="com.opensymphony.xwork2.interceptor.AliasInterceptor"/>

     .....

拦截器是struts的核心。

action

 package com.alibaba.struts2;

 public class HelloWorld

 {

     private String msg;

     public String getMessage()

     {

         return msg;

     }

     public String excute()

     {

         this.msg = "Hello,This is my frist struts2 app.";

         return "success";

     }

 }

jsp

 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

 <html>

   <head>

     <title>My JSP 'helloWorld.jsp' starting page</title>

     <meta http-equiv="pragma" content="no-cache">

     <meta http-equiv="cache-control" content="no-cache">

     <meta http-equiv="expires" content="0">

     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

     <meta http-equiv="description" content="This is my page">

     <!--

     <link rel="stylesheet" type="text/css" href="styles.css">

     -->

   </head>

   <body>

       ${message}

   </body>

 </html>

注：EL表达式中的参数和action中的getMessage()中的Message要一致。