怎麼說呢，今天是接觸Struts2的第二天了。關於Struts2來說，也不能說難。只能說複雜。也難怪，WEB這個方向能龐大，裏面的東西能不復雜嗎。但話又說回來，複雜也有其複雜的好處。比如，
jsp+javaBean簡單，但那是往小了說，如果項目足夠龐大，Struts2 的好處就顯現出來了。產品不是做出來就算牛逼了。關鍵還是在於後期的維護，如果項目的擴展性很好，耦合度很小，那麼後期的維護 也便方便些。所以不管怎麼講，再複雜也得研究，也得學。只要不是笨到只會左腳邁步的人，什麼東西都是能學會的。廢話也不多講了。
關於Struts2的學習，只要是對大家有好處的東西，我都會及時寫博客的，望大家一塊學習，一塊進步。
a、 使用領域對象接受用戶輸入：input接受參數的名字要命成領域對象.名稱(user.username, user.password)。原理：通過Struts2框架的數據綁定機制，傳遞user.username請求參數等同於調用：action.getUser().setUsername(…)。
實例：
<%@ 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>
用戶名和密碼錯誤，請重新登錄<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的屬性接受用戶輸入。也就是把<input>裏的user.username和user.password轉換成username和password。而在LoginAction.java中直接定義username和password屬性。不再使用User。同時也要生成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 stub
return user;
}
}
LoginAction實現了ModelDriven接口，表單字段就不需要再使用“user.”前綴了。