struts2_全局的拦截器，拦截用户非法登陆

struts都是通过action来请求页面的，所以可以通过全局的拦截器来拦截用户的非法登陆，如果用户知道jsp页面的地址，这种情况基本不会出现，那就需要用过滤器对页面进行过滤拦截了.

这里用拦截器进行拦截.

firtpart.xml:(设定默认的拦截器，每个Action都会默认调用)

<?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="test" extends="struts-default" namespace="/test">

        <interceptors>
            <interceptor name="loginJudge"
                class="com.sunflower.interceptor.UsrLoginInterceptor">
            </interceptor>

            <!-- 自定义拦截器栈 -->
            <interceptor-stack name="myDefaultStack">
                <interceptor-ref name="loginJudge"></interceptor-ref>
                <interceptor-ref name="defaultStack"></interceptor-ref>
            </interceptor-stack>
        </interceptors>

        <!-- 将自定义拦截器栈设置默认的拦截器 -->
        <default-interceptor-ref name="myDefaultStack"></default-interceptor-ref>

        <global-results>
    <result name="login" type="redirect">/login.jsp</result>
        </global-results>

        <action name="logintest" class="com.sunflower.action.LoginAction">
            <result name="success" type="redirectAction">
                <param name="actionName">sayhello</param>
                <param name="namespace">/test</param>
                <param name="username">${username}</param>
            </result>
        </action>
        
        <action name="sayhello" class="com.sunflower.action.SayHelloAction">
            <result name="success">/welcome.jsp</result>
            <result name="login">/login.jsp</result>
        </action>
    </package>
</struts>

 sturts.xml:(引用firtpart.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>
    <include file="firtpart.xml"></include>
</struts>

UsrLoginInterceptor.java:(拦截器，对所有Action拦截，除了登陆Action)

package com.sunflower.interceptor;

import java.util.Map;

import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;
import com.sunflower.action.LoginAction;

/**
 * 用户拦截器,每个页面都会用到
 * 
 * @author hanyuan
 * @time 2012-6-6 下午12:38:05
 */
public class UsrLoginInterceptor extends AbstractInterceptor {

    /**
     * 判断用户是否已经登录，如果没有登录，则为非法请求，进行拦截
     */
    public String intercept(ActionInvocation arg0) throws Exception {
        // 判断是否请求为登录界面(login),如果是则不拦截
        if (LoginAction.class == arg0.getAction().getClass())
            return arg0.invoke();
        
        
        // 如果是请求其他页面，进行拦截
        Map map = arg0.getInvocationContext().getSession();
        if (null == map.get("username"))
            return Action.LOGIN;

        return arg0.invoke();
    }

}

 LoginAction.java:(进行登陆校验)

package com.sunflower.action;

import java.util.Map;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.sunflower.util.UserExist;

public class LoginAction extends ActionSupport {
    private String username;
    private String password;

    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;
    }

    public String execute() throws Exception {
        // 设置session
        Map map = ActionContext.getContext().getSession();
        // 如果用户存在
        if (UserExist.isExist(username, password)) {
            if (null == map.get("username"))
                map.put("username", username);
            return SUCCESS;
        }

        return LOGIN;
    }
}

SayHelloAction.java:(转向欢迎界面的action)

package com.sunflower.action;

import com.opensymphony.xwork2.ActionSupport;

public class SayHelloAction extends ActionSupport {
    String username;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String execute() throws Exception {
        return SUCCESS;
    }
}

UserExist.java:(模拟用户校验的类)

package com.sunflower.util;

public class UserExist {
    //判断用户是否存在
    public static boolean isExist(String username, String password)
    {
        String name = username.trim();
        String word = password.trim();
        
        if(name.equals("yuan") && word.equals("123"))
            return true;
        return false;
    }
}    

login.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ 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>登录界面</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>
        <center>
            <font color="bule" size="20">用户登录</font>
            <br>
            <s:form action="test/logintest">
                <s:textfield name="username" label="用户名:" size="20"></s:textfield>
                <s:textfield name="password" label="密码:" size="20"></s:textfield>
                <s:submit value="提交"></s:submit>
            </s:form>

        </center>
    </body>
</html>

welcome.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!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>登陆成功</title>
    </head>
    <body>
        <center>
            <s:property value="username"/>,恭喜你登录成功！
        </center>        
    </body>
</html>