当你听到memcache与memcached时把它当做是一个东东就好了,尽管它们存在区别,但是这并不影响你对它们的运用及理解。

“Memcache”它是一个自由和开放源代码、高性能、分配的内存对象缓存系统,即该系统名称为“Memcache”;

“Memcached”它是该系统的主程序文件,以守护程序方式运行于一个或多个服务器中(分布式),随时接受客户端的连接操作,使用共享内存存取数据;

“Memcachedb”它是新浪2007年的项目,在Memcached的基础上开发出来了,它与Memcache不同的是它提供了数据持久化存储

 源代码地址:http://code.google.com/p/memcached/downloads/list

 

首先,我们需要下载一个memcached安装程序,memcached版本很多,开源的东西我们一定要找一个持续更新的版本,很简单,有团队在维护升级。

我选择的版本是:beitmemcached,项目地址:http://code.google.com/p/beitmemcached/  注:此链结为windows下memcached文程序安装文件及示例。

 

http://code.google.com/p/beitmemcached/downloads/list

 

图中的两个文件分别为:上面的是客户端调用示例项目文件、下面的文件是Memcached主程序安装文件

 

然后,将memcached主程序文件安装到服务器上。

Windows下安装:

1.将上图中Memcached 1.2.5.zip解压缩到 D:\program files\memcached目录下(此目录自行定义)。

2.Ctrl+R,输入cmd,打开命令行窗口,转到D:\program files\memcached目录下。

3.memcached.exe -d install

4.memcached.exe -d start

如果你要卸载,执行下面的命令:

1.memcached.exe -d stop

2.memcached.exe -d uninstall

Linux(CentOS 5.x)下安装:

1. yum install gcc

2. cd /tmp

3. wget http://www.monkey.org/~provos/libevent-2.0.4-alpha.tar.gz   注:memcached 用到了 libevent 这个库用于 Socket 的处理,所以 还需要安装 libevent

4. tar zxvf libevent-2.0.4-alpha.tar.gz

5. cd libevent-2.0.4-alpha

6. ./configure -prefix=/usr/local/libevent

7. make

8. make install

9. cd ~

10. cd /tmp

11. http://memcached.googlecode.com/files/memcached-1.4.5.tar.gz

12. tar zxvf memcached-1.4.5.tar.gz

13. cd memcached-1.4.5

14. ./configure -prefix=/usr/local/memcached --with-libevent=/usr/local/libevent    注:安装memcached时需要指定libevent的安装位置

15. make

16. make install

17. export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/libevent/lib   注:将libevent的lib目录加入LD_LIBRARY_PATH里

18. vi /etc/sysconfig/iptables 

19. 将下面这行加入进去

-A RH-Firewall-l-INPUT -p tcp -m tcp --dport 11211 -j ACCEPT  注:将memcached加入到防火墙允许访问规则中

20. service iptables restart  注:防火墙重启

21. /usr/local/memcached/bin/memcached -d   注:启动memcached

 

memcached启动参数描述:

-d :启动一个守护进程,

-m:分配给Memcache使用的内存数量,单位是MB,默认是64MB,

-u :运行Memcache的用户

-l  :监听的服务器IP地址

-p :设置Memcache监听的端口,默认是11211    注:-p(p为小写)

-c :设置最大并发连接数,默认是1024

-P :设置保存Memcache的pid文件   注:-P(P为大写)

如果要结束Memcache进程,执行:kill cat pid文件路径

 

无论是在windows下还是在linux下安装都非常简单,使用起来也很简单。

如何往memcached中插入数据?如何来读取数据?示例代码如下:

using System;
using System.Collections.Generic;

namespace BeIT.MemCached {
    class Example {
        public static void Main(string[] args) {
            //---------------------
            // Setting up a client.
            //---------------------
            Console.Out.WriteLine("Setting up Memcached Client.");
            MemcachedClient.Setup("MyCache", new string[] { "localhost" });

            //It is possible to have several clients with different configurations:
            //If it is impossible to resolve the hosts, this method will throw an exception.
            try {
                MemcachedClient.Setup("MyOtherCache", new string[]{ "server1.example.com:12345", "server2.example.com:12345"});
            } catch (Exception e) {
                Console.WriteLine(e.Message);
            }

            //Get the instance we just set up so we can use it. You can either store this reference yourself in
            //some field, or fetch it every time you need it, it doesn't really matter.
            MemcachedClient cache = MemcachedClient.GetInstance("MyCache");

            //It is also possible to set up clients in the standard config file. Check the section "beitmemcached"
            //in the App.config file in this project and you will see that a client called "MyConfigFileCache" is defined.
            MemcachedClient configFileCache = MemcachedClient.GetInstance("MyConfigFileCache");

            //Change client settings to values other than the default like this:
            cache.SendReceiveTimeout = 5000;
            cache.ConnectTimeout = 5000;
            cache.MinPoolSize = 1;
            cache.MaxPoolSize = 5;

            //----------------
            // Using a client.
            //----------------

            //Set some items
            Console.Out.WriteLine("Storing some items.");
            cache.Set("mystring", "The quick brown fox jumped over the lazy dog.");
            cache.Set("myarray", new string[]{"This is the first string.", "This is the second string."});
            cache.Set("myinteger", 4711);
            cache.Set("mydate", new DateTime(2008, 02, 23));
            //Use custom hash
            cache.Set("secondstring", "Flygande b鋍kasiner s鰇a hwila p?mjuka tufvor", 4711);

            //Get a string
            string str = cache.Get("mystring") as string;
            if (str != null) {
                Console.Out.WriteLine("Fetched item with key: mystring, value: " + str);
            }

            //Get an object
            string[] array = cache.Get("myarray") as string[];
            if (array != null) {
                Console.Out.WriteLine("Fetched items with key: myarray, value 1: " + array[0] + ", value 2: " + array[1]);
            }

            //Get several values at once
            object[] result = cache.Get(new string[]{"myinteger", "mydate"});
            if (result[0] != null && result[0] is int) {
                Console.Out.WriteLine("Fetched item with key: myinteger, value: " + (int)result[0]);
            }
            if (result[1] != null && result[1] is DateTime) {
                Console.Out.WriteLine("Fetched item with key: mydate, value: " + (DateTime)result[1]);
            }

            str = cache.Get("secondstring", 4711) as string;
            if (str != null) {
                Console.Out.WriteLine("Fetched item with key and custom hash: secondstring, value: " + str);
            }

            //Set a counter
            Console.Out.WriteLine("Setting an item for incrementing and decrementing.");
            cache.SetCounter("mycounter", 9000);
            ulong? counter = cache.GetCounter("mycounter");
            if (counter.HasValue) {
                Console.Out.WriteLine("Fetched mycounter, value: " + counter.Value);
            }

            //Increment the counter
            counter = cache.Increment("mycounter", 1);
            if (counter.HasValue) {
                Console.Out.WriteLine("Incremented mycounter with 1, new value: " + counter.Value);
            }

            //Decrement the counter
            counter = cache.Decrement("mycounter", 9000);
            if (counter.HasValue) {
                Console.Out.WriteLine("Decremented mycounter with 9000, new value: " + counter.Value);
            }

            //Append and prepend
            Console.Out.WriteLine("Storing bar for append/prepend");
            cache.Set("foo", "bar");
            Console.Out.WriteLine("Appending baz");
            cache.Append("foo", " baz");
            Console.Out.WriteLine("Prepending foo");
            cache.Prepend("foo", "foo ");
            Console.Out.WriteLine("New value: " + cache.Get("foo"));

            //Cas
            cache.Delete("castest");
            Console.Out.WriteLine("Trying to CAS non-existant key castest: " + cache.CheckAndSet("castest", "a", 0));
            Console.Out.WriteLine("Setting value for key: castest, value: a");
            cache.Set("castest", "a");
            Console.Out.WriteLine("Trying to CAS key castest with the wrong unique: " + cache.CheckAndSet("castest", "a", 0));
            ulong unique;
            cache.Gets("castest", out unique);
            Console.Out.WriteLine("Getting cas unique for key castest: " + unique);
            Console.Out.WriteLine("Trying to CAS again with the above unique: " + cache.CheckAndSet("castest", "b", unique));
            string value = cache.Gets("castest", out unique) as string;
            Console.Out.WriteLine("New value: " + value + ", new unique: " + unique);

            Console.Out.WriteLine("Displaying the socketpool status:");
            foreach (KeyValuePair<string, Dictionary<string, string>> host in cache.Status()) {
                Console.Out.WriteLine("Host: " + host.Key);
                foreach (KeyValuePair<string, string> item in host.Value) {
                    Console.Out.WriteLine("\t" + item.Key + ": " + item.Value);
                }
                Console.Out.WriteLine();
            }

            Console.Out.WriteLine();
            Console.Out.WriteLine("Finished. Press enter to exit.");
            Console.In.ReadLine();
        }
    }

}

 

 

注:memcached是以KEY-VALUE的方式进行数据存储的,KEY的大小限制:Key(max)<=250个字符;VALUE在存储时有 限制:Value(max)<= 1M;memcached默认过期时间:ExpiresTime(max)= 30(days)。

 

posted on 2012-04-18 23:37  袁晓平  阅读(195)  评论(0编辑  收藏  举报