Memcached 初探

技术入门

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安装

1. 安装 Memcached

以 Ubuntu 为例：

sudo apt-get install memcached

Memcached 项目主页，这里可以了解 memcached 的一些基本信息。

2. 安装客户端

Java 客户端 spymemcached

下载地址

Python 客户端

待定

使用

1. 启动多个 Memcached 实例

memcached -m 64 -p 11211 -u jiawzhang
memcached -m 64 -p 11212 -u jiawzhang

2. telnet 客户端访问

$ telnet localhost 11211
# set key-value
# 0: flag for client, 60: expire time, 5: bytes length, 'value' is 5 bytes-length
set key 0 60 5
value
STORED
# get key-value
get key
VALUE key 0 5
value
END
# Ctrl+] and quit 退出 telnet

3. Java spymemcached 客户端示例

示例 1：

MemcachedClient c=new MemcachedClient(
    new InetSocketAddress("hostname", portNum));
// Store a value (async) for one hour
c.set("someKey", 3600, someObject);
// Retrieve a value (synchronously).
Object myObject=c.get("someKey");

示例 2：

// Get a memcached client connected to several servers
MemcachedClient c=new MemcachedClient(
        AddrUtil.getAddresses("server1:11211 server2:11211"));
// Try to get a value, for up to 5 seconds, and cancel if it doesn't return
Object myObj=null;
Future<Object> f=c.asyncGet("someKey");
try {
    myObj=f.get(5, TimeUnit.SECONDS);
} catch(TimeoutException e) {
    // Since we don't need this, go ahead and cancel the operation.  This
    // is not strictly necessary, but it'll save some work on the server.
    f.cancel(false);
    // Do other timeout related stuff
}

更多详细示例

相关资料

1. Memcached入门指南

   http://www.cnblogs.com/javapro/archive/2012/05/24/2516016.html

2. Memcached 入门-介绍-使用-优化

   http://leiwuluan.iteye.com/blog/1173402

3. 一致性 hash 算法（ consistent hashing ）

   大多数 Memcached 客户端例如 spymemcached 支持一致性 hash，算法原理：

   http://blog.csdn.net/sparkliang/article/details/5279393