Spring Security 3.x 完整入门教程

Spring Security 3.x 出来一段时间了，跟Acegi是大不同了，与2.x的版本也有一些小小的区别，网上有一些文档，也有人翻译Spring Security 3.x的guide，但通过阅读guide，无法马上就能很容易的实现一个完整的实例。

我花了点儿时间，根据以前的实战经验，整理了一份完整的入门教程，供需要的朋友们参考。
1，建一个web project，并导入所有需要的lib，这步就不多讲了。
2，配置web.xml，使用Spring的机制装载：

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext*.xml</param-value>
</context-param>

<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>

<filter>
<filter-name>springSecurityFilterChain</filter-name>
<filter-class>
org.springframework.web.filter.DelegatingFilterProxy
</filter-class>
</filter>
<filter-mapping>
<filter-name>springSecurityFilterChain</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>
</web-app>

这个文件中的内容我相信大家都很熟悉了，不再多说了。

2，来看看applicationContext-security.xml这个配置文件，关于Spring Security的配置均在其中：

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/security"
xmlns:beans="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-3.0.xsd">
<http access-denied-page="/403.jsp"><!-- 当访问被拒绝时，会转到403.jsp -->
<intercept-url pattern="/login.jsp" filters="none" />
<form-login login-page="/login.jsp"
authentication-failure-url="/login.jsp?error=true"
default-target-url="/index.jsp" />
<logout logout-success-url="/login.jsp" />
<http-basic />
<!-- 增加一个filter，这点与Acegi是不一样的，不能修改默认的filter了，这个filter位于FILTER_SECURITY_INTERCEPTOR之前 -->
<custom-filter before="FILTER_SECURITY_INTERCEPTOR"
ref="myFilter" />
</http>

<!-- 一个自定义的filter，必须包含authenticationManager,accessDecisionManager,securityMetadataSource三个属性，
我们的所有控制将在这三个类中实现，解释详见具体配置 -->
<beans:bean id="myFilter" class="com.robin.erp.fwk.security.MyFilterSecurityInterceptor">
<beans:property name="authenticationManager"
ref="authenticationManager" />
<beans:property name="accessDecisionManager"
ref="myAccessDecisionManagerBean" />
<beans:property name="securityMetadataSource"
ref="securityMetadataSource" />
</beans:bean>

<!-- 认证管理器，实现用户认证的入口，主要实现UserDetailsService接口即可 -->
<authentication-manager alias="authenticationManager">
<authentication-provider
user-service-ref="myUserDetailService">
<!-- 如果用户的密码采用加密的话，可以加点“盐”
<password-encoder hash="md5" />
-->
</authentication-provider>
</authentication-manager>
<beans:bean id="myUserDetailService"
class="com.robin.erp.fwk.security.MyUserDetailService" />

<!-- 访问决策器，决定某个用户具有的角色，是否有足够的权限去访问某个资源 -->
<beans:bean id="myAccessDecisionManagerBean"
class="com.robin.erp.fwk.security.MyAccessDecisionManager">
</beans:bean>

<!-- 资源源数据定义，即定义某一资源可以被哪些角色访问 -->
<beans:bean id="securityMetadataSource"
class="com.robin.erp.fwk.security.MyInvocationSecurityMetadataSource" />

</beans:beans>

3，来看看自定义filter的实现：

package com.robin.erp.fwk.security;
import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;

public class MyFilterSecurityInterceptor extends AbstractSecurityInterceptor
package com.robin.erp.fwk.security;
import java.util.ArrayList;
import java.util.Collection;

import org.springframework.dao.DataAccessException;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.GrantedAuthorityImpl;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;

package com.robin.erp.fwk.security;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.access.SecurityConfig;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;
import org.springframework.security.web.util.AntUrlPathMatcher;
import org.springframework.security.web.util.UrlMatcher;

public class MyInvocationSecurityMetadataSource
package com.robin.erp.fwk.security;
import java.util.Collection;
import java.util.Iterator;

import org.springframework.security.access.AccessDecisionManager;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.access.SecurityConfig;
import org.springframework.security.authentication.InsufficientAuthenticationException;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;

在这个类中，最重要的是decide方法，如果不存在对该资源的定义，直接放行；否则，如果找到正确的角色，即认为拥有权限，并放行，否则throw new AccessDeniedException("no right");这样，就会进入上面提到的403.jsp页面。