Struts2初步认识

Struts2 由 struts.xml xxx.java web.xml xxx.jsp 组成

执行的规则是：首先访问 xxx1.jsp ,显示 xx1.jsp 界面，一番操作后访问服务器的请求被 web.xml 拦截，然后对应的 struts.xml 中 action 被激活，action 中相应的类 xxx.java 执行，执行后放回一个 String 类型的值，然后继续查找 action 中 result 的 name 属性，执行相应 result 对应的 xxx2.jsp

项目图：

web.xml 是配置拦截器的。

<?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></display-name>    
  <welcome-file-list>  未指定打开界面时，系统自动选择的最开始的界面（这里是列表，可以有多项）
    <welcome-file>index.jsp</welcome-file>  欢迎界面，优先级从上到下
  </welcome-file-list>
  <filter> 拦截器
      <filter-name>struts2</filter-name>拦截器名称
      <filter-class> 拦截器使用的拦截类类
          org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
      </filter-class>
  </filter>
  <filter-mapping>拦截器映射
      <filter-name>struts2</filter-name>要对应前面的名称
      <url-pattern>/*</url-pattern>拦截的类型
  </filter-mapping></web-app>

xxx.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'index.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>
    <form action="zhua">   此处的action要对应Struts.xml中配置的action名称！！！！！！！！！！！！！！
        <ul style="list-style-type: none;"> 
            <li>账号：<input type="text" name="zhanghao"> </li>
            <li>密码：<input type="text" name="mima"> </li>
            <li><input type="submit" value="提交"> </li>
        </ul>
    </form>  
  </body>
</html>

struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">
<struts>
    <package name="sss" extends="struts-default"> 包名可以自己定，扩展 struts-default（默认的）(不知道原因)
        <action name="zhua" class="text.Zhua"> action！！名称为 zhua ，对应的类为 text.Zhua （action的名称应与 xxx.jsp中form标签的action一致）
            <result name="ok">/ok.jsp</result> 对应返回值，显示相应的界面
            <result name="no">/no.jsp</result>
        </action>
    </package>
</struts>

xxx.java

package text;

import com.opensymphony.xwork2.ActionSupport;

public class Zhua extends ActionSupport 继承类
{
    private String zhanghao; 定义账号与密码
    private String mima;
    public String getZhanghao()
    {
        return zhanghao;
    }
    public void setZhanghao(String zhanghao)
    {
        this.zhanghao = zhanghao;
    }
    public String getMima()
    {
        return mima;
    }
    public void setMima(String mima)
    {
        this.mima = mima;
    }
    @Override
    public String execute() throws Exception 重要的方法
    {
        System.out.println(zhanghao+mima);
        // TODO Auto-generated method stub
        if(zhanghao.equals("chen"))
        {
            if(mima.equals("chang"))
            {
                return "ok"; 返回值ok
            }
        }
        return "xx"; 返回值no
    }
}

ok.jsp 跳转的界面，基本不用改动

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'ok.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>
    ok <br> 唯一更改的地方
  </body>
</html>