qq_44776721的博客

首先是互斥锁。优点：能够根据请求的key加锁，提高了并发性。缺点：GC不友好，不是分布式的。public final class MutexLock { private static final ConcurrentHashMap<String,CountDownLatch> locks=new ConcurrentHashMap<>(); public static boolean tryLock(String key){ //能过滤掉后持