Spring中使用Ehcache的方法和注意事项

 如何调用方法数据增加缓存
 @Cacheable(value="MY_CACHE", key="'cache_business_' + #business_id")
 public ShopCacheData loadShopData(long business_id) throws SQLException{
         ...
         return scd;
 }

 如何通过调用清空缓存
 @CacheEvict(value="MY_CACHE",  key="'cache_business_' + #business_id")        //allEntries=true
 public void cleanBusinessFromCache(long business_id) throws SQLException {
        return;
 }

 上面使用Cacheable注释的方式，如果在同一个Class中调用则缓存无效。

 如：

 public class ShopManager{

 @Cacheable(value="MY_CACHE", key="'cache_business_' + #business_id")
 public ShopCacheData loadShopData(long business_id) throws SQLException{
         ...
         return scd;
 }

 如何通过调用清空缓存
 @CacheEvict(value="MY_CACHE",  key="'cache_business_' + #business_id")        //allEntries=true
 public void cleanBusinessFromCache(long business_id) throws SQLException {
        return;
 }

 public void readShop(){

     ShopCacheData shop = loadShopData(1000);    //此处调用每次都会执行方法体，而不会使用相映的缓存

     ....

 }

 }

 解决办法:必须在方法中手工写入对Ehcache操作的代码才能起到作用

 public class ShopManager{

 @Cacheable(value="MY_CACHE", key="'cache_business_' + #business_id")
 public ShopCacheData loadShopData(long business_id) throws SQLException{
         ShopCacheData scd = null;
         ...
         Element el = null;
         CacheManager manager = CacheManager.create();
         // 通过manager可以生成指定名称的Cache对象
         Cache cache = manager.getCache("MY_CACHE");
         if(cache.isKeyInCache("cache_business_"+business_id)){
             el = cache.get("cache_business_"+business_id);
             return (ShopCacheData)el.getObjectValue();
         }
         //在缓存中没有找到对应的key则从数据库读取相关信息，并在得到后将结果放入缓存
         scd = loadShopDatafromDb(business_id);
         if(scd!=null){
                 el = new Element("cache_business_"+business_id, scd);
                 cache.put(el);
         }
         return scd;
 }

 @CacheEvict(value="MY_CACHE",  key="'cache_business_' + #business_id")        //allEntries=true
 public void cleanBusinessFromCache(long business_id) throws SQLException {
         CacheManager manager = CacheManager.create();     //通过manager可以生成指定名称的Cache对象
         Cache cache = manager.getCache("MY_CACHE");
         if(cache.isKeyInCache("cache_business_"+business_id)){   //将指定key的缓存对象从缓存中清除
             cache.remove("cache_business_"+business_id);
         }
        return;
 }

 public void readShop(){

     ShopCacheData shop = loadShopData(1000);   //此时调用缓存将有效

     ....

 }

 }

如何调用方法数据增加缓存
@Cacheable(value="MY_CACHE", key="'cache_business_' + #business_id")
public ShopCacheData loadShopData(long business_id) throws SQLException{
        ...
        return scd;
}

如何通过调用清空缓存
@CacheEvict(value="MY_CACHE",  key="'cache_business_' + #business_id")        //allEntries=true
public void cleanBusinessFromCache(long business_id) throws SQLException {
       return;
}

上面使用Cacheable注释的方式，只能在Controller中调用使缓存有效，如果在同一个Class中调用则缓存无效。

如：

public class ShopManager{

@Cacheable(value="MY_CACHE", key="'cache_business_' + #business_id")
public ShopCacheData loadShopData(long business_id) throws SQLException{
        ...
        return scd;
}

如何通过调用清空缓存
@CacheEvict(value="MY_CACHE",  key="'cache_business_' + #business_id")        //allEntries=true
public void cleanBusinessFromCache(long business_id) throws SQLException {
       return;
}

public void readShop(){

ShopCacheData shop = loadShopData(1000);    //此处调用每次都会执行方法体，而不会使用相映的缓存

....

}

}

解决办法:必须在方法中手工写入对Ehcache操作的代码才能起到作用

public class ShopManager{

@Cacheable(value="MY_CACHE", key="'cache_business_' + #business_id")
public ShopCacheData loadShopData(long business_id) throws SQLException{
        ShopCacheData scd = null;
        ...
        Element el = null;
        CacheManager manager = CacheManager.create();
        // 通过manager可以生成指定名称的Cache对象
        Cache cache = manager.getCache("MY_CACHE");
        if(cache.isKeyInCache("cache_business_"+business_id)){
            el = cache.get("cache_business_"+business_id);
            return (ShopCacheData)el.getObjectValue();
        }
        //在缓存中没有找到对应的key则从数据库读取相关信息，并在得到后将结果放入缓存
        scd = loadShopDatafromDb(business_id);
        if(scd!=null){
                el = new Element("cache_business_"+business_id, scd);
                cache.put(el);
        }
        return scd;
}

@CacheEvict(value="MY_CACHE",  key="'cache_business_' + #business_id")        //allEntries=true
public void cleanBusinessFromCache(long business_id) throws SQLException {
        CacheManager manager = CacheManager.create();     //通过manager可以生成指定名称的Cache对象
        Cache cache = manager.getCache("MY_CACHE");
        if(cache.isKeyInCache("cache_business_"+business_id)){   //将指定key的缓存对象从缓存中清除
            cache.remove("cache_business_"+business_id);
        }
       return;
}

public void readShop(){

ShopCacheData shop = loadShopData(1000);   //此时调用缓存将有效

....

}

}