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:
最核心的代码就是invoke方法中的InterceptorStatusToken token = super.beforeInvocation(fi);这一句,即在执行doFilter之前,进行权限的检查,而具体的实现已经交给accessDecisionManager了,下文中会讲述。
4,来看看authentication-provider的实现:

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;



public class MyUserDetailService implements UserDetailsService
{

@Override
public UserDetails loadUserByUsername(String username)

throws UsernameNotFoundException, DataAccessException
{
Collection<GrantedAuthority> auths=new ArrayList<GrantedAuthority>();
GrantedAuthorityImpl auth2=new GrantedAuthorityImpl("ROLE_ADMIN");
auths.add(auth2);

if(username.equals("robin1"))
{
auths=new ArrayList<GrantedAuthority>();
GrantedAuthorityImpl auth1=new GrantedAuthorityImpl("ROLE_ROBIN");
auths.add(auth1);
}
// User(String username, String password, boolean enabled, boolean accountNonExpired,
// boolean credentialsNonExpired, boolean accountNonLocked, Collection<GrantedAuthority> authorities) {
User user = new User(username,
"robin", true, true, true, true, auths);
return user;
}
}
在这个类中,你就可以从数据库中读入用户的密码,角色信息,是否锁定,账号是否过期等,我想这么简单的代码就不再多解释了。
5,对于资源的访问权限的定义,我们通过实现FilterInvocationSecurityMetadataSource这个接口来初始化数据。
看看loadResourceDefine方法,我在这里,假定index.jsp和i.jsp这两个资源,需要ROLE_ADMIN角色的用户才能访问。
这个类中,还有一个最核心的地方,就是提供某个资源对应的权限定义,即getAttributes方法返回的结果。注意,我例子中使用的是AntUrlPathMatcher这个path matcher来检查URL是否与资源定义匹配,事实上你还要用正则的方式来匹配,或者自己实现一个matcher。
6,剩下的就是最终的决策了,make a decision,其实也很容易,呵呵。

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;




public class MyAccessDecisionManager implements AccessDecisionManager
{

//In this method, need to compare authentication with configAttributes.
// 1, A object is a URL, a filter was find permission configuration by this URL, and pass to here.
// 2, Check authentication has attribute in permission configuration (configAttributes)
// 3, If not match corresponding authentication, throw a AccessDeniedException.
public void decide(Authentication authentication, Object object,
Collection<ConfigAttribute> configAttributes)

throws AccessDeniedException, InsufficientAuthenticationException
{

if(configAttributes == null)
{
return ;
}
System.out.println(object.toString()); //object is a URL.
Iterator<ConfigAttribute> ite=configAttributes.iterator();

while(ite.hasNext())
{
ConfigAttribute ca=ite.next();
String needRole=((SecurityConfig)ca).getAttribute();

for(GrantedAuthority ga:authentication.getAuthorities())
{

if(needRole.equals(ga.getAuthority()))
{ //ga is user‘s role.
return;
}
}
}
throw new AccessDeniedException("no right");
}

@Override

public boolean supports(ConfigAttribute attribute)
{
// TODO Auto-generated method stub
return true;
}

@Override

public boolean supports(Class<?> clazz)
{
return true;
}


}

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。
Spring Security 3.x 完整入门教程
原文:http://www.cnblogs.com/jizhuan/p/5092288.html