spring缓存集成memcache

wlyyb521

　　spring3.1.0开始支持注解方式的缓存实现，非常方便，不过它目前只支持java内置的ConcurrentMap和ehcache这两种缓存方式，因为项目用到memcache，就想把memcache集成到spring内置的缓存中，使memcache也能用注解方式来调用。于是参考ehcache的集成方式，把memcache集成到项目中。spring把所有缓存都抽象为一个cache，相当于一个缓存集合，即spring缓存注解@Cacheable(value="xxx")中xxx对应的结果集合。首先我们要实现Cache这个接口，memcache的java客户端我们用的是com.danga.MemCached.MemCachedClient这个，代码如下：

public class MemcacheCache implements Cache {
private MemCachedClient client;
private String name;
public MemcacheCache(){
}
public MemcacheCache(String name,MemCachedClient client) {
Assert.notNull(client, "Memcache client must not be null");
// TODO validate memcache "alive"
this.client = client;
this.name = name;
}
@Override
@Cacheable(value="xxxx")
public String getName() {
return this.name;
}
@Override
public Object getNativeCache() {
return this.client;
}
@Override
public ValueWrapper get(Object key) {
Object value = this.client.get(objectToString(key));
return (value != null ? new SimpleValueWrapper(value) : null);
}
@Override
public void put(Object key, Object value) {
this.client.set(objectToString(key), value);
}
@Override
public void evict(Object key) {
this.client.delete(objectToString(key));
}
@Override
public void clear() {
// TODO delete all data   
}
private static String objectToString(Object object) {
if (object == null) {
return null;
} else if (object instanceof String) {
return (String) object;
} else {
return object.toString();
}
}
public void setClient(MemCachedClient client){
this.client = client;
}
public MemCachedClient getClient() {
return client;
}
public void setName(String name) {
this.name = name;
}
}

　　

然后是要扩展AbstractCacheManager这个缓存管理抽象类，它主要负责生成和读取Cache，代码如下：

public class MemcacheCacheManager extends AbstractCacheManager {
private Collection<Cache> caches;
private MemCachedClient client = null;
public MemcacheCacheManager() {
}
public MemcacheCacheManager(MemCachedClient client){
setClient(client);
}
@Override
protected Collection<? extends Cache> loadCaches() {   
return this.caches;
}
public void setCaches(Collection<Cache> caches) {
this.caches = caches;
}
public void setClient(MemCachedClient client) {
this.client = client;
updateCaches();
}
public Cache getCache(String name){
checkState();
Cache cache = super.getCache(name);
if(cache == null){
cache = new MemcacheCache(name, client);
addCache(cache);
}
return cache;
}
private void checkState() {
if(client == null){
throw new IllegalStateException(&quot;MemcacheClient must not be null.&quot;);
}
//TODO check memcache state
}
private void updateCaches() {
if(caches != null){
for(Cache cache : caches){
if(cache instanceof MemcacheCache){
MemcacheCache memcacheCache = (MemcacheCache)cache;
memcacheCache.setClient(client);
}
}
}
}
}
　　配置bean：

<bean id=&quot;cacheManager&quot; class=&quot;com.youboy.cshop.utils.memcache.MemcacheCacheManager&quot;>
<property name=&quot;client&quot; value=&quot;memcachedClient&quot;/>
<property name=&quot;caches&quot;>
<set>
<bean class=&quot;com.youboy.cshop.utils.memcache.MemcacheCache&quot;>
<property name=&quot;name&quot; value=&quot;testCache&quot;/>
<property name=&quot;client&quot; ref=&quot;memcachedClient&quot;/>
</bean>
</set>
</property>
</bean>
　　

其中memcachedClient为你memcache的客户端，你可以配置多个MemcacheCache，配置完这里你就你就可以把@Cacheable(value=&quot;testCache&quot;)添加到方法那来缓存执行结果，这里value=&quot;testCache&quot;的&#20540;必须和上面bean文件配置的一致，否则无法缓存。这只是做了个简单的集成，还有很多要完善的，比如连接时检查memcache状态。

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