Struts2接受数据的三种方式
怎么说呢，今天是接触Struts2的第二天了。关于Struts2来说，也不能说难。只能说复杂。也难怪，WEB这个方向能庞大，里面的东西能不复杂吗。但话又说回来，复杂也有其复杂的好处。比如，
jsp+javaBean简单，但那是往小了说，如果项目足够庞大，Struts2 的好处就显现出来了。产品不是做出来就算牛逼了。关键还是在于后期的维护，如果项目的扩展性很好，耦合度很小，那么后期的维护 也便方便些。所以不管怎么讲，再复杂也得研究，也得学。只要不是笨到只会左脚迈步的人，什么东西都是能学会的。废话也不多讲了。
关于Struts2的学习，只要是对大家有好处的东西，我都会及时写博客的，望大家一块学习，一块进步。
a、 使用领域对象接受用户输入：input接受参数的名字要命成领域对象.名称(user.username, user.password)。原理：通过Struts2框架的数据绑定机制，传递user.username请求参数等同于调用：action.getUser().setUsername(…)。
实例：
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%><%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="login.action" method="post"> <table> <tr> <td> Username:<input type="text" name="user.username" /> </td> </tr> <tr> <td> Password:<input type="password" name="user.password" /> </td> </tr> <tr> <td> <input type="submit" value="Save"> </td> </tr> </table> </form> </body></html>
User.java:public class User {public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}private String username;private String password;}LoginAction.java:import com.opensymphony.xwork2.Action;public class LoginAction implements Action{private User user;public User getUser() {return user;}public void setUser(User user) {this.user = user;}public String execute() throws Exception {if("cuijun".equals(user.getUsername()) && "123".equals(user.getPassword())){return SUCCESS;}return ERROR;}}
Success.jsp:<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%><%@taglib prefix="s" uri="/struts-tags" %><%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> <h3><s:property value="user.username" /></h3> </body></html>error.jsp:<%@ page language="java" import="java.util.*" pageEncoding="gbk"%><%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> 用户名和密码错误，请重新登录<a href="login.jsp"> </body></html>struts.xml:<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN""http://struts.apache.org/dtds/struts-2.3.dtd"><struts> <package name="default" extends="struts-default"> <action name="login" class="LoginAction"> <result>/success.jsp</result> <result name="error">/error.jsp</result> </action> </package></struts>
a、直接使用action的属性接受用户输入。也就是把<input>里的user.username和user.password转换成username和password。而在LoginAction.java中直接定义username和password属性。不再使用User。同时也要生成username和password的setter和getter方法。
b、使用ModelDriven action。只需把修改LoginAction.java，如下:
import com.opensymphony.xwork2.Action;import com.opensymphony.xwork2.ModelDriven;public class LoginAction implements Action, ModelDriven{private User user = new User();public String execute() throws Exception {if("cuijun".equals(user.getUsername()) && "123".equals(user.getPassword())){return SUCCESS;}return ERROR;}public Object getModel() {// TODO Auto-generated method stubreturn user;}}
LoginAction实现了ModelDriven接口，表单字段就不需要再使用“user.”前缀了。