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