(转)实战Memcached缓存系统（6）Memcached CAS的多线程程序实例

1. 源程序

package com.sinosuperman.memcached;

import java.io.IOException;
import java.net.InetSocketAddress;

import net.spy.memcached.CASResponse;
import net.spy.memcached.CASValue;
import net.spy.memcached.MemcachedClient;


public class Test {

    private static MemcachedClient client = null;

    static {
        try {
            client = new MemcachedClient(new InetSocketAddress("localhost", 11211));
        } catch (IOException o) {
        }
    }

    public static void main(String[] args) throws Exception {

        client.set("numberss", 1800, 1);

        Test testObj = new Test();
        for (int i = 0; i < 10; i++) {
            testObj.new ThreadTest("Thread-" + (i + 1)).start();
        }
    }

    private class ThreadTest extends Thread {

        private  MemcachedClient client = null;
        ThreadTest(String name) throws IOException {
            super(name);
            client = new MemcachedClient(new InetSocketAddress("localhost", 11211));
        }

        public void run() {
            int i = 0;
            int success = 0;
            while (i < 10) {
                i++;
                CASValue<Object> uniqueValue =client.gets("numberss");
                CASResponse response = client.cas("numberss",
                 uniqueValue.getCas(), (Integer)uniqueValue.getValue() + 1);

                if (response.toString().equals("OK")) {
                    success++;
                }

                if (i == 10)
                System.out.println(Thread.currentThread().getName() + " " +  i
                  + " time " + " update oldValue : " + uniqueValue.getValue()
                  +  " , result : " + response);
            }

            if (success < 10) {
                Count.incr(10 - success);
                System.out.println("Test counter: " + Count.get());
            }
        }
    }

    public static class Count {
        private static int counter = 0;
        public static void incr(int x) {
            counter += x;
        }
        public static int get() {
            return counter;
        }
    }
}

2. 输出结果：

Thread-1 10 time  update oldValue : 14 , result : EXISTS
Test counter: 6
Thread-2 10 time  update oldValue : 14 , result : EXISTS
Test counter: 15
Thread-3 10 time  update oldValue : 17 , result : EXISTS
Test counter: 22
Thread-5 10 time  update oldValue : 17 , result : EXISTS
Test counter: 27
Thread-4 10 time  update oldValue : 20 , result : OK
Test counter: 33
Thread-8 10 time  update oldValue : 27 , result : OK
Test counter: 36
Thread-6 10 time  update oldValue : 28 , result : EXISTS
Test counter: 43
Thread-10 10 time  update oldValue : 31 , result : EXISTS
Test counter: 52
Thread-9 10 time  update oldValue : 31 , result : OK
Test counter: 60
Thread-7 10 time  update oldValue : 35 , result : OK
Test counter: 65

3. 分析

我们可以看到，未成功的次数最终为65，数据值最终为35，两者的和刚好是100，正好符合我们的实验结果预期。