Spring中使用Ehcache的方法和注意事项
1 如何调用方法数据增加缓存 2 @Cacheable(value="MY_CACHE", key="'cache_business_' + #business_id") 3 public ShopCacheData loadShopData(long business_id) throws SQLException{ 4 ... 5 return scd; 6 } 7 8 如何通过调用清空缓存 9 @CacheEvict(value="MY_CACHE", key="'cache_business_' + #business_id") //allEntries=true 10 public void cleanBusinessFromCache(long business_id) throws SQLException { 11 return; 12 } 13 14 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。 15 16 如： 17 18 public class ShopManager{ 19 20 @Cacheable(value="MY_CACHE", key="'cache_business_' + #business_id") 21 public ShopCacheData loadShopData(long business_id) throws SQLException{ 22 ... 23 return scd; 24 } 25 26 如何通过调用清空缓存 27 @CacheEvict(value="MY_CACHE", key="'cache_business_' + #business_id") //allEntries=true 28 public void cleanBusinessFromCache(long business_id) throws SQLException { 29 return; 30 } 31 32 33 public void readShop(){ 34 35 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 36 37 .... 38 39 } 40 41 } 42 43 44 45 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 46 47 public class ShopManager{ 48 49 @Cacheable(value="MY_CACHE", key="'cache_business_' + #business_id") 50 public ShopCacheData loadShopData(long business_id) throws SQLException{ 51 ShopCacheData scd = null; 52 ... 53 Element el = null; 54 CacheManager manager = CacheManager.create(); 55 // 通过manager可以生成指定名称的Cache对象 56 Cache cache = manager.getCache("MY_CACHE"); 57 if(cache.isKeyInCache("cache_business_"+business_id)){ 58 el = cache.get("cache_business_"+business_id); 59 return (ShopCacheData)el.getObjectValue(); 60 } 61 //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 62 scd = loadShopDatafromDb(business_id); 63 if(scd!=null){ 64 el = new Element("cache_business_"+business_id, scd); 65 cache.put(el); 66 } 67 return scd; 68 } 69 70 @CacheEvict(value="MY_CACHE", key="'cache_business_' + #business_id") //allEntries=true 71 public void cleanBusinessFromCache(long business_id) throws SQLException { 72 CacheManager manager = CacheManager.create(); //通过manager可以生成指定名称的Cache对象 73 Cache cache = manager.getCache("MY_CACHE"); 74 if(cache.isKeyInCache("cache_business_"+business_id)){ //将指定key的缓存对象从缓存中清除 75 cache.remove("cache_business_"+business_id); 76 } 77 return; 78 } 79 80 81 public void readShop(){ 82 83 ShopCacheData shop = loadShopData(1000); //此时调用缓存将有效 84 85 .... 86 87 } 88 89 }
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
....
}
}
