Memcached

Memcache是一套开源，高性能的分布式的内存对象缓存系统。Memcache将所有数据存储在内存中，并在内存里维护一个统一的巨大的Hash表，它能存储任意类型的数据，包括图像、视频、文件以及数据库检索的结果等。将数据调用到内存中，然后从内存中读取，从而大大提高读取速度

安装Memcached

（1）下载和安装libevent

git clone https://github.com/linxuping/libevent.git
./configure -prefix=/usr/local/libevent
make
make install

（2）下载和安装memcached

tar -xvzf memcached-1.5.16.tar.gz
./configure -prefix=/usr/local/memcached -with-libevent=/usr/local/libevent
make
make install

（3）启动memcached

./memcached -u root -d -m 128 -p 11211
./memcached -u root -d -m 128 -p 11212
./memcached -u root -d -m 128 -p 11213

（4）查看memcached进程

ps -ef | grep memcached

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（5）操作memcached

telnet 192.168.138.130 11211
set key 0 0 4
abcd
get key

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Java操作Memcached

package com.memcache.util;

import net.spy.memcached.MemcachedClient;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.Serializable;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

/**
 * @author Administrator
 * @version 1.0
 */
public class Memcache {
    private MemcachedClient client;

    /**
     * 连接memcached
     * @throws IOException
     */
    @Before
    public void connectClient() throws IOException {
        client = new MemcachedClient(new InetSocketAddress("192.168.138.130",11211));
    }


    /**
     * 设置key
     * @throws ExecutionException
     * @throws InterruptedException
     */
    @Test
    public void setKey() throws ExecutionException, InterruptedException {
        Future<Boolean> future = client.set("key1", 0, "Hello World");
        if (future.get().booleanValue()){
            client.shutdown();
        }
    }

    @Test
    public void getKey(){
        Object o = client.get("key1");
        System.out.println("取到的值: "+o);
        client.shutdown();
    }

    /**
     * 设置对象的值
     * @throws ExecutionException
     * @throws InterruptedException
     */
    @Test
    public void setObject() throws ExecutionException, InterruptedException {
        Future<Boolean> future = client.set("key2", 0, new Student());
        if (future.get().booleanValue()){
            client.shutdown();
        }
    }

    /**
     * 客户端路由算法
     * @throws IOException
     * @throws InterruptedException
     */
    @Test
    public void connectList() throws IOException, InterruptedException {
        ArrayList<InetSocketAddress> list = new ArrayList<>();
        list.add(new InetSocketAddress("192.168.138.130",11211));
        list.add(new InetSocketAddress("192.168.138.130",11212));
        list.add(new InetSocketAddress("192.168.138.130",11213));

        //连接Memcached
        client = new MemcachedClient(list);

        for (int i = 0; i < 10; i++){
            client.set("key"+i,0,"value"+i);
            Thread.sleep(1000);
        }

        client.shutdown();
    }
}
class Student implements Serializable {}