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。

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原文链接：
http://blog.csdn.net/poechant/article/details/7082842