在struts2中action的分類有：繼承 ActionSupport 實現 Action，模型驅動（ModelDriven）的 Action，多方法的 Action三種方式。
1、繼承 ActionSupport 實現 Action
通過繼承 ActionSupport 來實現 Action 是我們的推薦做法，因爲 ActionSupport 中提供了輸入驗證、國際化、execute 等常用方法，使得編寫 Action 時代碼很簡單。
1.1 UserAction.java
package com.lzugis.action;
import com.opensymphony.xwork2.ActionSupport;
public class UserAction extends ActionSupport
{
/**
*
*/
private static final long serialVersionUID = 1L;
private String username;
private String userpass;
public String getUsername()
{
return username;
}
public void setUsername(String username)
{
this.username = username;
}
public String getUserpass()
{
return userpass;
}
public void setUserpass(String userpass)
{
this.userpass = userpass;
}
@Override
public String execute() throws Exception
{
if (username.equals("admin") && userpass.equals("admin"))
{
return "success";
}
else
{
return "error";
}
}
}1.2 struts.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <!-- 定義包管理配置的action 繼承struts-default.xml中的配置 --> <package name="action" extends="struts-default"> <!-- 定義Action(login.action) --> <action name="login" class="com.lzugis.action.UserAction"> <!-- 定義轉發路徑對應的字符串名 --> <result name="success">/Success.jsp</result> <result name="error">/Error.jsp</result> </action> </package> </struts>
1.3 userlogin.jsp
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>用戶登錄</title>
</head>
<body style="font-family:Times New Roman">
<form action="login.action" method="post">
用戶名:
<!-- 參數名和action中的屬性名一樣 -->
<input type="text" name="username"><br>
密 碼:
<input type="password" name="userpass">
<br>
<input type="submit" name="subm" value="提交">
<input type="reset" name="reset" value="取消">
</form>
</body>
</html>1.4 action響應結果
1.4.1 Success.jsp
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <%@ taglib uri="/struts-tags" prefix="s"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>登錄成功</title> </head> <body> <h1>歡迎<s:property value="username" />,登錄</h1> </body> </html>
1.4.2 Error.jsp
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>登陸錯誤</title> </head> <body> <h1>用戶名或者密碼錯誤</h1> </body> </html>
2、模型驅動（ModelDriven）的 Action
Struts2 的 Action 屬於 MVC 模型層， Action 中的方法代表業務邏輯， Action 中的屬性代表請求中的參數，當頁面請求參數較多的時候，把過多的參數對象的屬性定義在 Action 中不太符合 Struts 所倡導的鬆耦合原則，所以我們推薦單獨用 JavaBean 來封裝參數，在 Action中爲 JavaBean 賦值，這就是 ModelDriven 的 Action。模型驅動的 Action 要求 Action 實現ModelDriven 接口，假如登錄頁面需要傳輸參數 username 和 userpass，我們把這 2 個參數封裝在一個數據的 JavaBean 中，然後在 Action 中定義該 JavaBean 爲 Model 即可。
2.1 UserInfo.java
package com.lzugis.javabean;
public class UserInfo
{
private String username,userpass;
public String getUsername()
{
return username;
}
public void setUsername(String username)
{
this.username=username;
}
public String getUserpass()
{
return userpass;
}
public void setUserpass(String userpass)
{
this.userpass=userpass;
}
}2.2 UserinfoAction.java
package com.lzugis.action;
import com.lzugis.javabean.UserInfo;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
public class UserinfoAction extends ActionSupport implements ModelDriven<UserInfo>
{
/**
*
*/
private static final long serialVersionUID = 1L;
private UserInfo model;
@Override
public UserInfo getModel()
{
if(model == null)
{
model = new UserInfo();
}
return model;
}
@Override
public String execute() throws Exception
{
if (model.getUsername().equals("admin") && model.getUserpass().equals("admin"))
{
return "success";
}
else
{
return "error";
}
}
}2.3 struts.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <!-- 定義包管理配置的action 繼承struts-default.xml中的配置 --> <package name="action" extends="struts-default"> <!-- 定義Action(user.action) --> <action name="user" class="com.lzugis.action.UserinfoAction"> <!-- 定義轉發路徑對應的字符串名 --> <result name="success">/Success.jsp</result> <result name="error">/Error.jsp</result> </action> </package> </struts>
2.4 user.jsp
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>用戶登錄</title>
</head>
<body style="font-family:Times New Roman">
<form action="user.action" method="post">
用戶名:
<!-- 參數名和action中的屬性名一樣 -->
<input type="text" name="model.username"><br>
密 碼:
<input type="password" name="model.userpass">
<br>
<input type="submit" name="subm" value="提交">
<input type="reset" name="reset" value="取消">
</form>
</body>
</html>2.5 action結果
與1相同，在此不在贅述。
本實例通過struts中action的兩種不同方式，實現了用戶登陸的驗證。相比較繼承ActionSupport實現action，模型驅動的action比較方便。繼承ActionSupport實現action，如果實體類的屬性非常多，那麼Action中也要定義相同的屬性，這樣顯得比較繁瑣。