Spymemcached 操作完成后挂起

Question

我正在使用 Spymemcached 访问服务器上的 Memcached。我使用以下命令启动 memcached

memcached -m 4096 -p 11211 -u memcache -l 127.0.0.1 -d -vvv

，并使用以下驱动程序将一些键/值对放入 Memcache 中。由于某种原因，在最后一次 get 操作之后，main 函数就挂起了；它永远不会终止。

import java.net.InetSocketAddress;
import net.spy.memcached.MemcachedClient;

public class memcache {
        public static void main(String args[]) {
                //Connect to Memcache.
                MemcachedClient c=null;
                try{   
                        c = new MemcachedClient(
                                new InetSocketAddress("127.0.0.1", 11211));
                } catch (Exception e) {
                        System.err.println("Could not connect to Memcached.");
                        System.exit(-1);
                }
                System.out.println("Connected to Memcached.");
                Object myObject = null;
                for (int i = 0; i < 10; i++)
                {
                        c.set(new String("HELLO"), 3600, i+1);
                        myObject=c.get("HELLO");
                        String value = myObject.toString();
                        System.out.println("***" + value);
                }
                System.out.println("Done.");
                return;
        }
}

我得到以下输出，但应用程序永远不会终止。

2011-12-04 14:18:31.839 INFO net.spy.memcached.MemcachedConnection:  Added {QA sa=/127.0.0.1:11211, #Rops=0, #Wops=0, #iq=0, topRop=null, topWop=null, toWrite=0, interested=0} to connect queue
Connected to Memcached.
2011-12-04 14:18:31.844 INFO net.spy.memcached.MemcachedConnection:  Connection state changed for sun.nio.ch.SelectionKeyImpl@578088c0
***1
Done.

服务器报告以下状态：

<32 server listening (udp)
<33 new auto-negotiating client connection
33: going from conn_new_cmd to conn_waiting
33: going from conn_waiting to conn_read
33: going from conn_read to conn_parse_cmd
33: Client using the ascii protocol
<33 set HELLO 512 3600 1
33: going from conn_parse_cmd to conn_nread
> NOT FOUND HELLO
>33 STORED
33: going from conn_nread to conn_write
33: going from conn_write to conn_new_cmd
33: going from conn_new_cmd to conn_waiting
33: going from conn_waiting to conn_read
33: going from conn_read to conn_parse_cmd
<33 get HELLO
> FOUND KEY HELLO
>33 sending key HELLO
>33 END
33: going from conn_parse_cmd to conn_mwrite
33: going from conn_mwrite to conn_new_cmd
33: going from conn_new_cmd to conn_waiting
33: going from conn_waiting to conn_read

什么问题可能导致 main 函数永远不会终止？有人有什么建议吗？

Answer 1

解决方案很简单。完成后客户端必须断开连接：

c.shutdown(...)

所有示例均不包含此关键步骤。