在struts2中使用拦截器（interceptor）控制登录和权限.txt

在jsp servlet中我们通常使用Servlet Filter控制用户是否登入

在jsp servlet中我们通常使用Servlet Filter控制用户是否登入， 是否有权限转到某个页面。在struts2中我们应该会想到他的拦截器（Interceptor）， Interceptor在struts2中起着非常重要的作用。 很多struts2中的功能都是使用Interceptor实现的。 

需求：简单的登入界面，让用户输入用户名、密码、记住密码（remember me）。 如果用户选中remember me的话， 下次就不需要再登入了（使用cookie实现， 用需要点击logout取消remeber me功能）。 如果用户起始输入的地址不是登入页面的话，在用户登入之后需要转到用户输入的起始地址。 

我们先看看LoginInterceptor.java 

Java代码 
package com.javaeye.dengyin2000.wallet.interceptor;    
   
import java.util.Map;    
   
import javax.servlet.http.Cookie;    
import javax.servlet.http.HttpServletRequest;    
   
import org.apache.commons.lang.StringUtils;    
import org.apache.struts2.StrutsStatics;    
   
import com.javaeye.dengyin2000.wallet.dao.UserDAO;    
import com.javaeye.dengyin2000.wallet.dao.UserNotFoundException;    
import com.javaeye.dengyin2000.wallet.domains.User;    
import com.opensymphony.xwork2.ActionContext;    
import com.opensymphony.xwork2.ActionInvocation;    
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;    
   
public class LoginInterceptor extends AbstractInterceptor {    
    public static final String USER_SESSION_KEY="wallet.session.user";    
    public static final String COOKIE_REMEMBERME_KEY="wallet.cookie.rememberme";    
    public static final String GOING_TO_URL_KEY="GOING_TO";    
        
    private UserDAO userDao;    
   
    @Override   
    public String intercept(ActionInvocation invocation) throws Exception {    
            
        ActionContext actionContext = invocation.getInvocationContext();    
        HttpServletRequest request= (HttpServletRequest) actionContext.get(StrutsStatics.HTTP_REQUEST);    
            
        Map session = actionContext.getSession();    
        if (session != null && session.get(USER_SESSION_KEY) != null){    
            return invocation.invoke();    
        }    
            
        Cookie[] cookies = request.getCookies();    
        if (cookies!=null) {    
            for (Cookie cookie : cookies) {    
                if (COOKIE_REMEMBERME_KEY.equals(cookie.getName())) {    
                    String value = cookie.getValue();    
                    if (StringUtils.isNotBlank(value)) {    
                        String[] split = value.split("==");    
                        String userName = split[0];    
                        String password = split[1];    
                        try {    
                            User user = userDao    
                                    .attemptLogin(userName, password);    
                            session.put(USER_SESSION_KEY, user);    
                        } catch (UserNotFoundException e) {    
                            setGoingToURL(session, invocation);    
                            return "login";    
                        }    
                    } else {    
                        setGoingToURL(session, invocation);    
                        return "login";    
                    }    
                    return invocation.invoke();    
                }    
            }    
        }    
        setGoingToURL(session, invocation);    
        return "login";    
    }    
   
    private void setGoingToURL(Map session, ActionInvocation invocation){    
        String url = "";    
        String namespace = invocation.getProxy().getNamespace();    
        if (StringUtils.isNotBlank(namespace) && !namespace.equals("/")){    
            url = url + namespace;    
        }    
        String actionName = invocation.getProxy().getActionName();    
        if (StringUtils.isNotBlank(actionName)){    
            url = url + "/" + actionName + ".action";    
        }    
        session.put(GOING_TO_URL_KEY, url);    
    }    
        
    public UserDAO getUserDao() {    
        return userDao;    
    }    
   
    public void setUserDao(UserDAO userDao) {    
        this.userDao = userDao;    
    }    
   
}   
package com.javaeye.dengyin2000.wallet.interceptor;
import java.util.Map;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.lang.StringUtils;
import org.apache.struts2.StrutsStatics;
import com.javaeye.dengyin2000.wallet.dao.UserDAO;
import com.javaeye.dengyin2000.wallet.dao.UserNotFoundException;
import com.javaeye.dengyin2000.wallet.domains.User;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;
public class LoginInterceptor extends AbstractInterceptor {
public static final String USER_SESSION_KEY="wallet.session.user";
public static final String COOKIE_REMEMBERME_KEY="wallet.cookie.rememberme";
public static final String GOING_TO_URL_KEY="GOING_TO";
private UserDAO userDao;
@Override
public String intercept(ActionInvocation invocation) throws Exception {
ActionContext actionContext = invocation.getInvocationContext();
HttpServletRequest request= (HttpServletRequest) actionContext.get(StrutsStatics.HTTP_REQUEST);
Map session = actionContext.getSession();
if (session != null && session.get(USER_SESSION_KEY) != null){
return invocation.invoke();
}
Cookie[] cookies = request.getCookies();
if (cookies!=null) {
for (Cookie cookie : cookies) {
if (COOKIE_REMEMBERME_KEY.equals(cookie.getName())) {
String value = cookie.getValue();
if (StringUtils.isNotBlank(value)) {
String[] split = value.split("==");
String userName = split[0];
String password = split[1];
try {
User user = userDao
.attemptLogin(userName, password);
session.put(USER_SESSION_KEY, user);
} catch (UserNotFoundException e) {
setGoingToURL(session, invocation);
return "login";
}
} else {
setGoingToURL(session, invocation);
return "login";
}
return invocation.invoke();
}
}
}
setGoingToURL(session, invocation);
return "login";
}
private void setGoingToURL(Map session, ActionInvocation invocation){
String url = "";
String namespace = invocation.getProxy().getNamespace();
if (StringUtils.isNotBlank(namespace) && !namespace.equals("/")){
url = url + namespace;
}
String actionName = invocation.getProxy().getActionName();
if (StringUtils.isNotBlank(actionName)){
url = url + "/" + actionName + ".action";
}
session.put(GOING_TO_URL_KEY, url);
}
public UserDAO getUserDao() {
return userDao;
}
public void setUserDao(UserDAO userDao) {
this.userDao = userDao;
}
}


首先判断session中有没有用户信息， 如果有的话继续， 如果没有的话，检查cookie中有没有rememberme的值，如果有的话，用==分割， 取得用户名密码进行登入。如果没有这个用户的话，记录下request的action地址然后转到登入页面。如果验证有这个用户，则继续下面的interceptor。 如果cookie中没有信息的话，则记录request的action地址然后转到登入页面。 以上就是LoginInterceptor的全部代码。 

下面我们看看struts.xml 


Java代码 
<?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>    
    <package name="default" extends="struts-default">    
        <interceptors>    
            <interceptor name="loginInterceptor" class="loginInterceptor"></interceptor>    
            <interceptor-stack name="loginDefaultStack">    
                <interceptor-ref name="loginInterceptor"></interceptor-ref>    
                <interceptor-ref name="defaultStack"></interceptor-ref>    
            </interceptor-stack>    
        </interceptors>    
        <default-interceptor-ref name="loginDefaultStack"></default-interceptor-ref>    
        <global-results>    
            <result name="login" type="redirect">/login.jsp</result>    
        </global-results>         
        <action name="index" class="indexAction">    
            <result>/index.jsp</result>    
        </action>    
        <action name="logout" class="logoutAction"></action>    
            
        <action name="login" class="loginAction" method="login">    
            <result type="redirect">${goingToURL}</result>    
            <result name="input">/login.jsp</result>    
            <interceptor-ref name="defaultStack"></interceptor-ref>    
        </action>    
            
        <action name="register" class="registerAction">    
            <result type="redirect">/login.jsp</result>    
            <result name="input">/register.jsp</result>    
            <interceptor-ref name="defaultStack"></interceptor-ref>    
        </action>    
    </package>    
</struts>   
<?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>
<package name="default" extends="struts-default">
<interceptors>
<interceptor name="loginInterceptor" class="loginInterceptor"></interceptor>
<interceptor-stack name="loginDefaultStack">
<interceptor-ref name="loginInterceptor"></interceptor-ref>
<interceptor-ref name="defaultStack"></interceptor-ref>
</interceptor-stack>
</interceptors>
<default-interceptor-ref name="loginDefaultStack"></default-interceptor-ref>
<global-results>
<result name="login" type="redirect">/login.jsp</result>
</global-results>
<action name="index" class="indexAction">
<result>/index.jsp</result>
</action>
<action name="logout" class="logoutAction"></action>
<action name="login" class="loginAction" method="login">
<result type="redirect">${goingToURL}</result>
<result name="input">/login.jsp</result>
<interceptor-ref name="defaultStack"></interceptor-ref>
</action>
<action name="register" class="registerAction">
<result type="redirect">/login.jsp</result>
<result name="input">/register.jsp</result>
<interceptor-ref name="defaultStack"></interceptor-ref>
</action>
</package>
</struts>


我们是使用的默认的interceptor stack是loginInterceptor， 如果你需要让不登入的用户也能访问的话，你需要配置你的action使用defaultStack。 我们这里的login, register使用的就是defaultStack。 这里要注意的是success的result是我们用LoginInterceptor设过来的值。 这样我们就能够转到用户输入的起始页面。 下面我们再来看看login.jsp 和 loginAction 


Java代码 
<%@taglib prefix="s" uri="/struts-tags" %>    
<%@ page language="java" contentType="text/html; charset=UTF-8"   
    pageEncoding="UTF-8"%>    
<html>    
<head>    
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">    
    <title>Wallet-Login</title>    
</head>    
<body>    
<h2>Login</h2>     
<s:actionmessage/>    
<s:actionerror/>    
<s:form action="login" method="post" validate="false" theme="xhtml">    
<s:textfield name="loginName" label="Username"></s:textfield><br/>    
<s:password name="password" label="Password"></s:password><br/>    
<s:checkbox label="Remember Me" name="rememberMe"></s:checkbox>    
<s:submit value="%{'Login'}"></s:submit>     
</s:form>    
<a href="register.jsp">Register</a>    
</body>    
</html>   
<%@taglib prefix="s" uri="/struts-tags" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Wallet-Login</title>
</head>
<body>
<h2>Login</h2>
<s:actionmessage/>
<s:actionerror/>
<s:form action="login" method="post" validate="false" theme="xhtml">
<s:textfield name="loginName" label="Username"></s:textfield><br/>
<s:password name="password" label="Password"></s:password><br/>
<s:checkbox label="Remember Me" name="rememberMe"></s:checkbox>
<s:submit value="%{'Login'}"></s:submit>
</s:form>
<a href="register.jsp">Register</a>
</body>
</html>



Java代码 
package com.javaeye.dengyin2000.wallet.actions;    
   
import java.util.Map;    
   
import javax.servlet.http.Cookie;    
import javax.servlet.http.HttpServletRequest;    
import javax.servlet.http.HttpServletResponse;    
   
import org.apache.commons.lang.StringUtils;