struts学习笔记--解决了struts action中的execute方法不执行的问题

　　最近开始学struts。先是抱着书看了几天，然后就动手想写个简单的登录程序。但是在写的过程中发现了页面上提交的请求可以被转发到自己写的action，但是action中的方法execute不执行，怎么都调不好。然后写了一个超级简单的程序，只有提交的操作，还是不行，郁闷。第二天跟别人一起找问题，最后终于解决了。

　　先说一下环境吧： MyEclipse5.5（机子太烂，版本高了跑不动），JAVASDK1.6，struts1.3.10。

　　项目的结构：　page1.jsp，page2.jsp，PageAction.java。 page1提交请求到PageAction.do，PageAction在控制台上打印"success"，返回一个"success"。跳转到page2.jsp。

原始代码：

page1.jsp

===========================================

<%@ page contentType="text/html; charset=UTF-8" %>
<form method="POST" action="PageAction.do">
<input type="submit" value="submit" />
</form>
===========================================

page2.jsp

===========================================

<%@ page contentType="text/html; charset=UTF-8" %>

<%
out.println("This is page2.jsp");
%>

===========================================

PageAction.java

===========================================

package com.action;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

import org.apache.struts.action.*;

public class PageAction extends Action {
public ActionForward execute(ActionMapping mapping,ActionForm form, ServletRequest request,
ServletResponse response) throws Exception {
System.out.println("success");
return mapping.findForward("success");
}
}

============================================

web.xml

============================================

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.5" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<init-param>
<param-name>debug</param-name>
<param-value>3</param-value>
</init-param>
<init-param>
<param-name>detail</param-name>
<param-value>3</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>

<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app>

=============================================

struts-config.xml

=============================================

<?xml version="1.0" encoding="ISO-8859-1" ?>

<!DOCTYPE struts-config PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"
"http://struts.apache.org/dtds/struts-config_1_3.dtd">

<struts-config>
<action-mappings>
<action path="/PageAction" type="com.action.PageAction" >
<forward name="success" path="/page2.jsp" />
</action>
</action-mappings>
</struts-config>

==============================================

最开始的时候总是点击page1上的按钮后显示一个空白页面，后台也不报错，超郁闷。怎么改都不行。后来看

Action 的源码发现 Action 把 execute 方法重载了。分别是：

=======================================================

public ActionForward execute(ActionMapping mapping, ActionForm form,
ServletRequest request, ServletResponse response)
throws Exception {
}

public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
}

=======================================================

然后跟踪程序的执行流程。 发现流程里有这样一个方法：

protected ActionForward processActionPerform(HttpServletRequest request,
HttpServletResponse response, Action action, ActionForm form,
ActionMapping mapping)
throws IOException, ServletException {
try {
return (action.execute(mapping, form, request, response));
} catch (Exception e) {
return (processException(request, response, e, form, mapping));
}
}

调用的是上边的第二个 execute 。把自己的 PageAction 中的 execute改了就能执行到 execute 了。终于搞定了。在网上看到有好多人都有这个问题，不知道大家和我遇到的情况一样不。

总结一下吧，学习还是不能急，遇到问题自己要慢慢找答案，这样能记得更牢，还有就是寻找错误要按照一定的步骤来，不能瞎找。第一次写博客，写得不怎么样，光贴代码了，呵呵。