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java - 如何在登录页面上确定是否有用户已经登录?

转载 作者:行者123 更新时间:2023-11-29 06:38:52 25 4
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有什么办法,如何确定在使用 Spring 3 MVC + Spring security 时是否有人已经登录?这是我的安全上下文:

<beans xmlns:security="http://www.springframework.org/schema/security"
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/security
http://www.springframework.org/schema/security/spring-security-3.1.xsd">

<security:http pattern="/resources/**" security="none"/>
<security:http pattern="/login*" security="none" auto-config="true"/>
<security:http pattern="/denied" security="none"/>

<security:http auto-config="true" access-denied-page="/denied" servlet-api-provision="false">
<security:intercept-url pattern="/login*" access="IS_AUTHENTICATED_ANONYMOUSLY"/>
<security:intercept-url pattern="/edit/**" access="ROLE_EDIT"/>
<security:intercept-url pattern="/admin/**" access="ROLE_ADMIN"/>
<security:intercept-url pattern="/**" access="ROLE_USER"/>
<security:form-login login-page="/login" authentication-failure-url="/denied"
default-target-url="/"/>
<security:logout/>
</security:http>

<security:authentication-manager>
<security:authentication-provider>
<security:user-service>
<security:user name="adam" password="adampassword" authorities="ROLE_USER"/>
<security:user name="jane" password="janepassword" authorities="ROLE_USER, ROLE_ADMIN"/>
<security:user name="sue" password="suepassword" authorities="ROLE_USER, ROLE_EDIT"/>
</security:user-service>
</security:authentication-provider>
</security:authentication-manager>

</beans>

我可以确定它,即在主页上通过

<%
User user = (User) SecurityContextHolder.getContext()
.getAuthentication().getPrincipal();
String username = user.getUsername();
%>

但是在登录页面上它会生成空指针异常.. :-/

当有人已经登录并且有人试图再次登录时,浏览器会转到 myurl.com/home 页面,我会收到 404 错误,因为正确的地址应该是myurl.com/。当没有人登录时,浏览器将重定向到正确的地址。有什么想法可能是错误吗?

我的jsp页面:

<%@ page import="org.springframework.security.core.userdetails.User"%>
<%@ page import="org.springframework.security.core.context.SecurityContextHolder"%>
<%@ page import="java.util.Collection"%>
<%@ page import="javax.swing.text.AbstractDocument"%>
<%@ page import="org.springframework.security.core.GrantedAuthority"%>

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
</head>
<body>
<div class="form">
<form name="f" action="j_spring_security_check" method="post">
<input type="text" id="username" class="input-block-level"
name="j_username" placeholder="Username"> <input
type="password" id="password" name="j_password"
class="input-block-level" placeholder="Password">
<button class="btn btn-large btn-primary" type="submit">Sign
in</button>
</form>
</div>
</body>
</html>

最佳答案

Spring Security 包含一个 JSP 标签库,可以通过下面的代码导入:

<%@ taglib prefix="sec" uri="http://www.springframework.org/security/tags" %>

导入后,您可以使用 jsp 标记“sec”(用于安全性),

 <sec:authorize access="isAuthenticated()">
... <!-- Code or message to show when user is authenticated -->
</sec:authorize>

在标签内,您可以运行某些代码、显示标签或html。

http://static.springsource.org/spring-security/site/docs/3.0.x/reference/taglibs.html

关于java - 如何在登录页面上确定是否有用户已经登录?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/15603801/

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