实例讲解DispatchAction和LookupDispatchAction

注意：以下两个例子在调试的过程中用的是同一个form和struts-config.xml，在调试的过程中DispatchAction是不用资源文件ApplicationResources.properties的，而LookupDispatchAction是要用到ApplicationResources.properties

先来说说DispatchAction，网上的许多例子都是和超链接来做的，其实用DispatchAction用按钮也是可以实现的，来看例子吧！

UserManagement.jsp

< %@ taglib uri ="http://struts.apache.org/tags-logic" prefix ="logic"% >
< %@taglib prefix ="c" uri ="http://java.sun.com/jsp/jstl/core"% >
< html >
   < head >
     < title >DispatchAction Example - viralpatel.net </title>
   </head>
   < body >
     < h2 >
      User Management (DispatchAction Example)
     </h2>
     < font color ="black" > < h3 >
        用struts标签的方法
       </h3> </font>
     < html:form action ="/user" method ="post" >
       < html:text property ="userName" />
       < html:submit property ="method" value ="create" />
       < html:submit property ="method" value ="delete" />
     </html:form>
     < font color ="black" > < h3 >
        不用struts标签的方法
       </h3> </font>
     < form action ="/struts_action_test/user.do" method ="post" >
       < input type ="text" name ="userName" />
       < input type ="submit" name ="method" value ="create" />
       < input type ="submit" name ="method" value ="delete" />
     </form>
     < font color ="blue" > < h3 >
        ${message }
       </h3> </font> 现有以下用户：
     < c:forEach var ="numArray" items ="${num}" >
       < table >
         < tr >
           < td >
             < c:out value ="${numArray}" />
           </td>
         </tr>
       </table>
     </c:forEach>
   </body>
</html>

UserManagementAction

package com.zgxr.struts;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.List;

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

import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.DispatchAction;

public class UserManagementAction extends DispatchAction {
   // 用于存放添加的用户
  List list = new ArrayList();
   public ActionForward create(ActionMapping mapping, ActionForm form,
      HttpServletRequest request, HttpServletResponse response)
       throws Exception {
    LoginActionForm loginActionForm = (LoginActionForm) form;
     // 将新添加的用户放入list
    list.add(loginActionForm.getUserName());
    request.setAttribute( "message", "User created successfully" + ":"
        + "当前用户数量为:" + list.size());
    
    request.setAttribute( "num", list);
     return mapping.findForward( "success");
  }

   public ActionForward delete(ActionMapping mapping, ActionForm form,
      HttpServletRequest request, HttpServletResponse response)
       throws Exception {
    LoginActionForm loginActionForm = (LoginActionForm) form;
     //将提交上来的用户从List中删除
    list.remove(loginActionForm.getUserName());
    request.setAttribute( "message", "User deleted successfully" + ":"
        + "当前用户数量为:" + list.size());
    request.setAttribute( "num", list);
     return mapping.findForward( "success");
  }

}

LoginActionForm:

package com.zgxr.struts;

import org.apache.struts.action.ActionForm;

public class LoginActionForm extends ActionForm {
   // 定义两个变量，这两个值与页面上的html:text的property的值相对应
   private int numOne;
   private int numTwo;
   private String userName;

   public String getUserName() {
     return userName;
  }

   public void setUserName(String userName) {
     this.userName = userName;
  }

   public int getNumOne() {
     return numOne;
  }

   public void setNumOne( int numOne) {
     this.numOne = numOne;
  }

   public int getNumTwo() {
     return numTwo;
  }

   public void setNumTwo( int numTwo) {
     this.numTwo = numTwo;
  }

}

struts-config.xml

<? xml version ="1.0" encoding ="UTF-8" ?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN" "http://struts.apache.org/dtds/struts-config_1_2.dtd">
< struts-config >
   < form-beans >
     < form-bean name ="loginActionForm"
       type ="com.zgxr.struts.LoginActionForm" >
     </ form-bean >
   </ form-beans >
   < action-mappings >
     < action path ="/user" parameter ="method" name ="loginActionForm"
       type ="com.zgxr.struts.UserManagementAction" >
       < forward name ="success" path ="/UserManagement.jsp" />
       < forward name ="failure" path ="/UserManagement.jsp" />
     </ action >

     < action path ="/test" name ="loginActionForm" scope ="request"
       parameter ="action" type ="com.zgxr.struts.TestAction"
       input ="/operation.jsp" >
       < forward name ="success" path ="/operation.jsp" />
       < forward name ="failure" path ="/operation.jsp" />
     </ action >
   </ action-mappings >
   < message-resources parameter ="ApplicationResources" />
</ struts-config >

好了把以上这些拷下来试试吧，下面我们来看看LookupDispatchAction

operation.jsp

%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
< %@ taglib uri ="http://struts.apache.org/tags-html" prefix ="html"% >
< %@ taglib prefix ="bean" uri ="http://struts.apache.org/tags-bean"% >

< !DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" >
< html >
   < head >
     < title >LookupDispatchAction Example - viralpatel.net </title>
   </head>
   < body >
     < h2 >
      User Management (LookupDispatch Action Example)
     </h2>
                            用struts标签的方法
     < html:form action ="/test" method ="post" >
       < html:text property ="numOne" />
       < html:text property ="numTwo" />
       < html:submit property ="action" >
         < bean:message     key ="button.sum" />
       </html:submit>
       < html:submit property ="action" >
         < bean:message key ="button.minus" />
       </html:submit>
       < html:submit property ="action" >
         < bean:message key ="button.multiply" />
       </html:submit>
       < html:submit property ="action" >
         < bean:message key ="button.divide" />
       </html:submit>
     </html:form>
                             不用struts标签的方法
                             < form name ="loginActionForm" method ="post" action="/struts_action_test/test.do >
       < input type ="text" name ="numOne" />
       < input type ="text" name ="numTwo" />
       < input type ="submit" name ="action" value ="sum" />
       < input type ="submit" name ="action" value ="minus" >
       < input type ="submit" name ="action" value ="multiply" />
       < input type ="submit" name ="action" value ="divide" />
     </form>
   </body>
</html>

TestAction:

package com.zgxr.struts;

import java.util.HashMap;
import java.util.Map;

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

import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.LookupDispatchAction;

public class TestAction extends LookupDispatchAction {

  @Override
   //用于关联按键和方法
   protected Map getKeyMethodMap() {
    Map map = new HashMap();
     //如果按钮标题的key为button.sum. 则提交该按钮时对应sum方法
    map.put( "button.sum", "sum");
     //如果按钮标题的key为button.minus. 则提交该按钮时对应minus方法
    map.put( "button.minus", "minus");
     //如果按钮标题的key为button.multiply. 则提交该按钮时对应multiply方法
    map.put( "button.multiply", "multiply");
     //如果按钮标题的key为button.divide. 则提交该按钮时对应divide方法
    map.put( "button.divide", "divide");
     return map;
  }

   public ActionForward sum(ActionMapping mapping, ActionForm form,
      HttpServletRequest request, HttpServletResponse response)
       throws Exception {
     //将form转变成提交时用到的loginActonForm
    LoginActionForm loginActionForm = (LoginActionForm) form;
     //计算加法
     int num = loginActionForm.getNumOne() + loginActionForm.getNumTwo();
    request.setAttribute( "action", num);
     return mapping.findForward( "success");
  }

   public ActionForward minus(ActionMapping mapping, ActionForm form,
      HttpServletRequest request, HttpServletResponse response)
       throws Exception {
     //将form转变成提交时用到的loginActonForm
    LoginActionForm loginActionForm = (LoginActionForm) form;
     //计算减法
     int num = loginActionForm.getNumOne() - loginActionForm.getNumTwo();
    request.setAttribute( "action", num);
     return mapping.findForward( "success");
  }

   public ActionForward multiply(ActionMapping mapping, ActionForm form,
      HttpServletRequest request, HttpServletResponse response)
       throws Exception {
     //将form转变成提交时用到的loginActonForm
    LoginActionForm loginActionForm = (LoginActionForm) form;
     //计算乘法
     int num = loginActionForm.getNumOne() * loginActionForm.getNumTwo();
    request.setAttribute( "action", num);
     return mapping.findForward( "success");
  }

   public ActionForward divide(ActionMapping mapping, ActionForm form,
      HttpServletRequest request, HttpServletResponse response)
       throws Exception {
     //将form转变成提交时用到的loginActonForm
    LoginActionForm loginActionForm = (LoginActionForm) form;
     //计算除法
     int num = loginActionForm.getNumOne() / loginActionForm.getNumTwo();
    request.setAttribute( "action", num);
     return mapping.findForward( "success");
  }
}

ApplicationResources.properties

button.sum=sum
button.minus=minus
button.multiply=multiply
button.divide=divide

好了就这么多了哦忘了web.xml了

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 >application </ param-name >
       < param-value >ApplicationResources </ param-value >
     </ init-param >
     < 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 >
   < welcome-file-list >
     < welcome-file >/UserManagement.jsp </ welcome-file >
   </ welcome-file-list >
</ web-app >

大家要注意了在不用struts标签的时候，form提交的路径要注意具体见以上代码