shiro安全框架擴展教程--如何擴展realm橋接器並退出自動清空角色資源緩存

        上一章節我們知道了如何擴展自己的緩存機制,下面我們就學習下如何應用自己的自定義緩存,我們登錄都必須要寫一個realm,就是所謂的橋接器;

鑑於我們登錄都會把擁有的角色放到緩存,這樣都不用每次請求都要訪問一次數據庫,導致亞歷山大,當退出的時候又如何自動我們登錄時添加的緩存數據

下面帖個展示代碼

package com.silvery.security.shiro.realm;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.AuthenticationInfo;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.authc.SimpleAuthenticationInfo;
import org.apache.shiro.authc.UsernamePasswordToken;
import org.apache.shiro.authz.AuthorizationInfo;
import org.apache.shiro.authz.SimpleAuthorizationInfo;
import org.apache.shiro.realm.AuthorizingRealm;
import org.apache.shiro.subject.PrincipalCollection;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;

import com.silvery.core.model.ViewResult;
import com.silvery.project.cms.model.Authority;
import com.silvery.project.cms.model.UserDetails;
import com.silvery.project.cms.service.AuthorityService;
import com.silvery.project.cms.service.UserDetailsService;
import com.silvery.project.cms.vo.AuthorityVo;
import com.silvery.project.cms.vo.UserDetailsVo;
import com.silvery.security.shiro.cache.SimpleMapCache;
import com.silvery.security.shiro.cache.extend.SimpleCacheManager;

/**
 * 
 * 安全框架橋接器
 * 
 * @author shadow
 * 
 */
public class SimpleUserRealm extends AuthorizingRealm {

	private final static Logger log = LoggerFactory.getLogger(SimpleUserRealm.class);

	@Autowired
	private UserDetailsService userDetailsService;

	@Autowired
	private AuthorityService authorityService;

	@Autowired
	private SimpleCacheManager simpleCacheManager;

	// 授權當前用戶信息
	protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {
		return getAuthorizationInfo(principals.getPrimaryPrincipal());
	}

	@SuppressWarnings("unchecked")
	private SimpleAuthorizationInfo getAuthorizationInfo(Object principal) {

		List<Authority> authorities = null;

		// 獲取緩存,如失敗緩存則返回空角色集合
		try {
			authorities = (List<Authority>) simpleCacheManager.getCache(principal.toString()).get(principal);
		} catch (Exception e) {
			authorities = new ArrayList<Authority>();
			log.error(e.getMessage());
		}

		SimpleAuthorizationInfo authorizationInfo = new SimpleAuthorizationInfo();

		// 添加角色到安全認證實體
		for (Authority authority : authorities) {
			authorizationInfo.addRole((authority.getName()));
		}

		return authorizationInfo;

	}

	// 用戶登錄認證
	protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken authcToken) throws AuthenticationException {

		UsernamePasswordToken token = (UsernamePasswordToken) authcToken;

		UserDetailsVo vo = new UserDetailsVo();
		vo.setUsername(token.getUsername());
		vo.setPassword(String.valueOf(token.getPassword()));
		vo.setJcaptionCode(token.getHost());

		// 使用用戶服務類接口查詢用戶是否存在
		ViewResult viewResult = userDetailsService.login(vo);

		if (viewResult.getSuccess()) {
			UserDetails details = (UserDetails) viewResult.getValue();
			// 加載用戶相應角色到緩存
			loadUserAuthorityTocache(details);
			// 返回安全框架認證信息
			return new SimpleAuthenticationInfo(details.getUsername(), details.getPassword(), getName());
		} else {
			log.debug(new StringBuffer().append(token.getUsername()).append(" login failure at ").append(
					new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())).append(", error message: ").append(
					viewResult.getMessage()).toString());
			// 失敗情況拋出異常並返回服務層相應錯誤信息
			throw new AuthenticationException(viewResult.getMessage());
		}

	}

	/**
	 * 加載用戶角色
	 * 
	 * @param details
	 */
	private void loadUserAuthorityTocache(UserDetails details) {

		// 使用當前用戶名作爲cache key
		String cacheKey = details.getUsername();

		AuthorityVo vo = new AuthorityVo();
		vo.setUser_id(details.getId());

		// 查詢用戶角色並存放到map
		Map<Object, Object> map = new HashMap<Object, Object>();
		map.put(cacheKey, authorityService.find4user(vo).getValue());

		// 新建cache實例並放入緩存管理器
		SimpleMapCache cache = new SimpleMapCache(cacheKey, map);
		simpleCacheManager.createCache(details.getUsername(), cache);

	}

	/** 重寫退出時緩存處理方法 */
	protected void doClearCache(PrincipalCollection principalcollection) {
		Object principal = principalcollection.getPrimaryPrincipal();
		simpleCacheManager.removeCache(principal.toString());
		log.debug(new StringBuffer().append(principal).append(" on logout to remove the cache [").append(principal)
				.append("]").toString());
	}

}

1. 明顯看到登錄流程中,我們使用自己定義的緩存管理器,登錄認證成功後,然後加載出該用戶的相關角色,然後放到緩存中

2. 用戶認證的時候,是通過我們的自定義緩存管理器讀取資源,實現我們不用第二次查詢數據庫的需求

3. 如何在退出的自動清空相關緩存呢?可以看到我是重寫doClearCache方法,爲何要重寫?先看看下面帖上來的源碼

public abstract class CachingRealm
    implements Realm, Nameable, CacheManagerAware, LogoutAware
{

    public CachingRealm()
    {
        cachingEnabled = true;
        name = (new StringBuilder()).append(getClass().getName()).append("_").append(INSTANCE_COUNT.getAndIncrement()).toString();
    }

    public CacheManager getCacheManager()
    {
        return cacheManager;
    }

    public void setCacheManager(CacheManager cacheManager)
    {
        this.cacheManager = cacheManager;
        afterCacheManagerSet();
    }

    public boolean isCachingEnabled()
    {
        return cachingEnabled;
    }

    public void setCachingEnabled(boolean cachingEnabled)
    {
        this.cachingEnabled = cachingEnabled;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    protected void afterCacheManagerSet()
    {
    }

    public void onLogout(PrincipalCollection principals)
    {
        clearCache(principals);
    }

    protected void clearCache(PrincipalCollection principals)
    {
        if(!CollectionUtils.isEmpty(principals))
        {
            doClearCache(principals);
            log.trace("Cleared cache entries for account with principals [{}]", principals);
        }
    }

    protected void doClearCache(PrincipalCollection principalcollection)
    {
    }

    protected Object getAvailablePrincipal(PrincipalCollection principals)
    {
        Object primary = null;
        if(!CollectionUtils.isEmpty(principals))
        {
            Collection thisPrincipals = principals.fromRealm(getName());
            if(!CollectionUtils.isEmpty(thisPrincipals))
                primary = thisPrincipals.iterator().next();
            else
                primary = principals.getPrimaryPrincipal();
        }
        return primary;
    }

    private static final Logger log = LoggerFactory.getLogger(org/apache/shiro/realm/CachingRealm);
    private static final AtomicInteger INSTANCE_COUNT = new AtomicInteger();
    private String name;
    private boolean cachingEnabled;
    private CacheManager cacheManager;

}

明顯看到有個方法onLogout處理安全退出時的動作,然後試着重寫這個方法加入我們remove cache的動作,這樣就可以完美實現退出的時候自動清空自己的角色資源緩存,

但是有人會問,如果我不使用安全退出那資源會一直保留嗎?

這個是肯定的,但是當他下次登錄,會重新加載資源覆蓋之前的角色資源緩存

這次的試驗比較簡單,但是實用,相信對大家會有幫助,謝謝