在struts2中action的分类有：继承 ActionSupport 实现 Action，模型驱动（ModelDriven）的 Action，多方法的 Action三种方式。
1、继承 ActionSupport 实现 Action
通过继承 ActionSupport 来实现 Action 是我们的推荐做法，因为 ActionSupport 中提供了输入验证、国际化、execute 等常用方法，使得编写 Action 时代码很简单。
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> <!-- 定义包管理配置的action 继承struts-default.xml中的配置 --> <package name="action" extends="struts-default"> <!-- 定义Action(login.action) --> <action name="login" class="com.lzugis.action.UserAction"> <!-- 定义转发路径对应的字符串名 --> <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>用户登录</title>
</head>
<body style="font-family:Times New Roman">
<form action="login.action" method="post">
用户名:
<!-- 参数名和action中的属性名一样 -->
<input type="text" name="username"><br>
密 码:
<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响应结果
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>登录成功</title> </head> <body> <h1>欢迎<s:property value="username" />,登录</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>登陆错误</title> </head> <body> <h1>用户名或者密码错误</h1> </body> </html>
2、模型驱动（ModelDriven）的 Action
Struts2 的 Action 属于 MVC 模型层， Action 中的方法代表业务逻辑， Action 中的属性代表请求中的参数，当页面请求参数较多的时候，把过多的参数对象的属性定义在 Action 中不太符合 Struts 所倡导的松耦合原则，所以我们推荐单独用 JavaBean 来封装参数，在 Action中为 JavaBean 赋值，这就是 ModelDriven 的 Action。模型驱动的 Action 要求 Action 实现ModelDriven 接口，假如登录页面需要传输参数 username 和 userpass，我们把这 2 个参数封装在一个数据的 JavaBean 中，然后在 Action 中定义该 JavaBean 为 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> <!-- 定义包管理配置的action 继承struts-default.xml中的配置 --> <package name="action" extends="struts-default"> <!-- 定义Action(user.action) --> <action name="user" class="com.lzugis.action.UserinfoAction"> <!-- 定义转发路径对应的字符串名 --> <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>用户登录</title>
</head>
<body style="font-family:Times New Roman">
<form action="user.action" method="post">
用户名:
<!-- 参数名和action中的属性名一样 -->
<input type="text" name="model.username"><br>
密 码:
<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结果
与1相同，在此不在赘述。
本实例通过struts中action的两种不同方式，实现了用户登陆的验证。相比较继承ActionSupport实现action，模型驱动的action比较方便。继承ActionSupport实现action，如果实体类的属性非常多，那么Action中也要定义相同的属性，这样显得比较繁琐。