32、shiro 框架入门三

1、AuthenticationStrategy实现

//在所有Realm验证之前调用
AuthenticationInfo beforeAllAttempts(
Collection<? extends Realm> realms, AuthenticationToken token)
throws AuthenticationException;
//在每个Realm之前调用
AuthenticationInfo beforeAttempt(
Realm realm, AuthenticationToken token, AuthenticationInfo aggregate)
throws AuthenticationException;
//在每个Realm之后调用
AuthenticationInfo afterAttempt(
Realm realm, AuthenticationToken token,
AuthenticationInfo singleRealmInfo, AuthenticationInfo aggregateInfo, Throwable t)
throws AuthenticationException;
//在所有Realm之后调用
AuthenticationInfo afterAllAttempts(
AuthenticationToken token, AuthenticationInfo aggregate)
throws AuthenticationException;

因为每个AuthenticationStrategy实例都是无状态的，所有每次都通过接口将相应的认证信息传入下一次流程；通过如上接口可以进行如合并/返回第一个验证成功的认证信息。

　　自定义实现时一般继承org.apache.shiro.authc.pam.AbstractAuthenticationStrategy

下边这个OnlyOneAuthenticatorStrategy只允许一个成功的验证信息，进行返回，否则会报AuthenticationException，只返回第一个验证成功的Realm的认证信息

public class OnlyOneAuthenticatorStrategy extends AbstractAuthenticationStrategy {

    @Override
    public AuthenticationInfo beforeAllAttempts(Collection<? extends Realm> realms, AuthenticationToken token) throws AuthenticationException {
        return new SimpleAuthenticationInfo();//返回一个权限的认证信息，在进行验证之前返回的信息，不对权限信息进行处理
    }

    @Override
    public AuthenticationInfo beforeAttempt(Realm realm, AuthenticationToken token, AuthenticationInfo aggregate) throws AuthenticationException {
        return aggregate;//返回之前合并的,在进行验证之前返回的信息，不对权限信息进行处理

  }
　  @Override
 　　public AuthenticationInfo afterAttempt(Realm realm, AuthenticationToken token, AuthenticationInfo singleRealmInfo, AuthenticationInfo aggregateInfo, Throwable t) throws AuthenticationException {
　　　　 AuthenticationInfo info; 
　　　　 if (singleRealmInfo == null) 
　　　　 {
　　　　　　 info = aggregateInfo; 
　　　　 } else
 　　　　{
　　　　　　 if (aggregateInfo == null) {
　　　　　　 info = singleRealmInfo;
　　　　 } else {
　　　　　　 info = merge(singleRealmInfo, aggregateInfo); 
　　　　　　 if(info.getPrincipals().getRealmNames().size() > 1) 
　　　　　　 {
　　　　　　　　 System.out.println(info.getPrincipals().getRealmNames());
　　　　　　　　 throw new AuthenticationException("Authentication token of type [" + token.getClass() + "] " + 
　　　　　　　　"could not be authenticated by any configured realms. Please ensure that only one realm can " +
　　　　　　　　 "authenticate these tokens."); 
　　　　　　 }
　　　　 }
　　 }
　　　　 return info;
 }
 @Override
 public AuthenticationInfo afterAllAttempts(AuthenticationToken token, AuthenticationInfo aggregate) throws AuthenticationException
 { 
　　　　return aggregate;
 }

 }

这里的shiro主要就是将多个AuthenticationToken信息合并在一起，

2、AbstractAuthenticationStrategy中的merge方法，主要就是先检查该

AuthenticationInfo 是不是可以merge的类型，如果是则将其转换为可以merge的类型，然后调用merge方法

/**
     * Merges the specified <code>info</code> argument into the <code>aggregate</code> argument and then returns an
     * aggregate for continued use throughout the login process.
     * <p/>
     * This implementation merely checks to see if the specified <code>aggregate</code> argument is an instance of
     * {@link org.apache.shiro.authc.MergableAuthenticationInfo MergableAuthenticationInfo}, and if so, calls
     * <code>aggregate.merge(info)</code>  If it is <em>not</em> an instance of
     * <code>MergableAuthenticationInfo</code>, an {@link IllegalArgumentException IllegalArgumentException} is thrown.
     * Can be overridden by subclasses for custom merging behavior if implementing the
     * {@link org.apache.shiro.authc.MergableAuthenticationInfo MergableAuthenticationInfo} is not desired for some reason.
     */
    protected AuthenticationInfo merge(AuthenticationInfo info, AuthenticationInfo aggregate) {
        if( aggregate instanceof MergableAuthenticationInfo ) {
            ((MergableAuthenticationInfo)aggregate).merge(info);
            return aggregate;
        } else {
            throw new IllegalArgumentException( "Attempt to merge authentication info from multiple realms, but aggregate " +
                      "AuthenticationInfo is not of type MergableAuthenticationInfo." );
        }
    }

可以进行多个AuthenticationInfo信息进行merge的功能如下所示，返回所有验证成功的Realm的认证信息

public class AtLeastTwoAuthenticatorStrategy extends AbstractAuthenticationStrategy {

    @Override
    public AuthenticationInfo beforeAllAttempts(Collection<? extends Realm> realms, AuthenticationToken token) throws AuthenticationException {
        return new SimpleAuthenticationInfo();//返回一个权限的认证信息
    }

    @Override
    public AuthenticationInfo beforeAttempt(Realm realm, AuthenticationToken token, AuthenticationInfo aggregate) throws AuthenticationException {
        return aggregate;//返回之前合并的
    }

    @Override
    public AuthenticationInfo afterAttempt(Realm realm, AuthenticationToken token, AuthenticationInfo singleRealmInfo, AuthenticationInfo aggregateInfo, Throwable t) throws AuthenticationException {
        AuthenticationInfo info;
        if (singleRealmInfo == null) {
            info = aggregateInfo;
        } else {
            if (aggregateInfo == null) {
                info = singleRealmInfo;
            } else {
                info = merge(singleRealmInfo, aggregateInfo);
            }
        }

        return info;
    }

    @Override
    public AuthenticationInfo afterAllAttempts(AuthenticationToken token, AuthenticationInfo aggregate) throws AuthenticationException {
        if (aggregate == null || CollectionUtils.isEmpty(aggregate.getPrincipals()) || aggregate.getPrincipals().getRealmNames().size() < 2) {
            throw new AuthenticationException("Authentication token of type [" + token.getClass() + "] " +
                    "could not be authenticated by any configured realms.  Please ensure that at least two realm can " +
                    "authenticate these tokens.");
        }

        return aggregate;
    }

3、对于Subject线程进行解绑

@After
    public void tearDown() throws Exception {
        ThreadContext.unbindSubject();//退出时请解除绑定Subject到线程 否则对下次测试造成影响
    }