spring security 3 自定义认证，授权示例

 

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：

 

    
        contextConfigLocation
        classpath:applicationContext*.xml
    

    
        
             org.springframework.web.context.ContextLoaderListener
        
    

    
        springSecurityFilterChain
        
             org.springframework.web.filter.DelegatingFilterProxy
        
    
    
        springSecurityFilterChain
        /*
    


    
        login.jsp
    

 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：

 

 3，来看看自定义filter的实现：

package com.example.spring.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
        implements Filter {

    private FilterInvocationSecurityMetadataSource securityMetadataSource;

    // ~ Methods
    // ========================================================================================================

    /**
      * Method that is actually called by the filter chain. Simply delegates to
      * the {@link #invoke(FilterInvocation)} method.
      * 
      * @param request
      *             the servlet request
      * @param response
      *             the servlet response
      * @param chain
      *             the filter chain
      * 
      * @throws IOException
      *              if the filter chain fails
      * @throws ServletException
      *              if the filter chain fails
     */
    public void doFilter(ServletRequest request, ServletResponse response,
             FilterChain chain) throws IOException, ServletException {
         FilterInvocation fi = new FilterInvocation(request, response, chain);
         invoke(fi);
     }

    public FilterInvocationSecurityMetadataSource getSecurityMetadataSource() {
        return this.securityMetadataSource;
     }

    public Class getSecureObjectClass() {
        return FilterInvocation.class;
     }

    public void invoke(FilterInvocation fi) throws IOException,
             ServletException {
         InterceptorStatusToken token = super.beforeInvocation(fi);
        try {
             fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
         } finally {
            super.afterInvocation(token, null);
         }
     }

    public SecurityMetadataSource obtainSecurityMetadataSource() {
        return this.securityMetadataSource;
     }

    public void setSecurityMetadataSource(
             FilterInvocationSecurityMetadataSource newSource) {
        this.securityMetadataSource = newSource;
     }

     @Override
    public void destroy() {
     }

     @Override
    public void init(FilterConfig arg0) throws ServletException {
     }

}

 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。

4，来看看authentication-provider的实现：

package com.example.spring.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 auths=new ArrayList();
         GrantedAuthorityImpl auth2=new GrantedAuthorityImpl("ROLE_ADMIN");
         auths.add(auth2);
        if(username.equals("robin1")){
             auths=new ArrayList();
             GrantedAuthorityImpl auth1=new GrantedAuthorityImpl("ROLE_ROBIN");
             auths.add(auth1);
         }
        
//         User(String username, String password, boolean enabled, boolean accountNonExpired,
//                     boolean credentialsNonExpired, boolean accountNonLocked, Collection 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。

package com.example.spring.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;
/**
* 
* 此类在初始化时，应该取到所有资源及其对应角色的定义
* 
* @author Robin
* 
*/
public class MyInvocationSecurityMetadataSource
        implements FilterInvocationSecurityMetadataSource {
    private UrlMatcher urlMatcher = new AntUrlPathMatcher();;
    private static Map> resourceMap = null;

    public MyInvocationSecurityMetadataSource() {
         loadResourceDefine();
     }

    private void loadResourceDefine() {
         resourceMap = new HashMap>();
         Collection atts = new ArrayList();
         ConfigAttribute ca = new SecurityConfig("ROLE_ADMIN");
         atts.add(ca);
         resourceMap.put("/index.jsp", atts);
         resourceMap.put("/i.jsp", atts);
     }

    // According to a URL, Find out permission configuration of this URL.
    public Collection getAttributes(Object object)
            throws IllegalArgumentException {
        // guess object is a URL.
         String url = ((FilterInvocation)object).getRequestUrl();
         Iterator ite = resourceMap.keySet().iterator();
        while (ite.hasNext()) {
             String resURL = ite.next();
            if (urlMatcher.pathMatchesUrl(url, resURL)) {
                return resourceMap.get(resURL);
             }
         }
        return null;
     }

    public boolean supports(Class clazz) {
        return true;
     }
    
    public Collection getAllConfigAttributes() {
        return null;
     }

}

 

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.example.spring.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 configAttributes)
            throws AccessDeniedException, InsufficientAuthenticationException {
        if(configAttributes == null){
            return ;
         }
         System.out.println(object.toString());  //object is a URL.
         Iterator 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