编程入门教程

Java 连接 Memcached 服务

使用 Java 程序连接 Memcached,需要在你的 classpath 中添加 Memcached jar 包。

Google Code jar 包下载地址: spymemcached-2.10.3.jar(需要翻墙)。

以下程序假定 Memcached 服务的主机为 127.0.0.1,端口为 11211。

连接实例

Java 连接 Memcached

import net.spy.memcached.MemcachedClient;
import java.net.*;


public class MemcachedJava {
   public static void main(String[] args) {
      try{
         // 本地连接 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");
         
         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex){
         System.out.println( ex.getMessage() );
      }
   }
}

该程序中我们使用 InetSocketAddress 连接 IP 为 127.0.0.1 端口 为 11211 的 memcached 服务。

执行以上代码,如果连接成功会输出以下信息:

Connection to server successful.

set 操作实例

以下使用 java.util.concurrent.Future 来存储数据

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

import net.spy.memcached.MemcachedClient;

public class MemcachedJava {
   public static void main(String[] args) {
   
      try{
         // 连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");
      
         // 存储数据
         Future fo = mcc.set("renren", 900, "Free Education");
      
         // 查看存储状态
         System.out.println("set status:" + fo.get());
         
         // 输出值
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex){
         System.out.println( ex.getMessage() );
      }
   }
}

执行程序,输出结果为:

Connection to server successful.
set status:true
renren value in cache - Free Education

add 操作实例

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

import net.spy.memcached.MemcachedClient;

public class MemcachedJava {
   public static void main(String[] args) {
   
      try{
   
         // 连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // 添加数据
         Future fo = mcc.set("renren", 900, "Free Education");

         // 打印状态
         System.out.println("set status:" + fo.get());

         // 输出
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 添加
         Future fo = mcc.add("renren", 900, "memcached");

         // 打印状态
         System.out.println("add status:" + fo.get());

         // 添加新key
         fo = mcc.add("codingground", 900, "All Free Compilers");

         // 打印状态
         System.out.println("add status:" + fo.get());
         
         // 输出
         System.out.println("codingground value in cache - " + mcc.get("codingground"));

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex){
         System.out.println(ex.getMessage());
      }
   }
}

replace 操作实例

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

import net.spy.memcached.MemcachedClient;

public class MemcachedJava {
   public static void main(String[] args) {
   
      try {
         //连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // 添加第一个 key=》value 对
         Future fo = mcc.set("renren", 900, "Free Education");

         // 输出执行 add 方法后的状态
         System.out.println("add status:" + fo.get());

         // 获取键对应的值
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 添加新的 key
         fo = mcc.replace("renren", 900, "Largest Tutorials' Library");

         // 输出执行 set 方法后的状态
         System.out.println("replace status:" + fo.get());

         // 获取键对应的值
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex){
         System.out.println( ex.getMessage() );
      }
   }
}

append 操作实例

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

import net.spy.memcached.MemcachedClient;

public class MemcachedJava {
   public static void main(String[] args) {
   
      try{
   
         // 连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // 添加数据
         Future fo = mcc.set("renren", 900, "Free Education");

         // 输出执行 set 方法后的状态
         System.out.println("set status:" + fo.get());

         // 获取键对应的值
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 对存在的key进行数据添加操作
         Future fo = mcc.append("renren", 900, " for All");

         // 输出执行 set 方法后的状态
         System.out.println("append status:" + fo.get());
         
         // 获取键对应的值
         System.out.println("renren value in cache - " + mcc.get("codingground"));

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex)
         System.out.println(ex.getMessage());
   }
}

prepend 操作实例

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

import net.spy.memcached.MemcachedClient;

public class MemcachedJava {
   public static void main(String[] args) {
   
      try{
   
         // 连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // 添加数据
         Future fo = mcc.set("renren", 900, "Education for All");

         // 输出执行 set 方法后的状态
         System.out.println("set status:" + fo.get());

         // 获取键对应的值
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 对存在的key进行数据添加操作
         Future fo = mcc.prepend("renren", 900, "Free ");

         // 输出执行 set 方法后的状态
         System.out.println("prepend status:" + fo.get());
         
         // 获取键对应的值
         System.out.println("renren value in cache - " + mcc.get("codingground"));

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex)
         System.out.println(ex.getMessage());
   }
}

CAS 操作实例

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

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

public class MemcachedJava {
   public static void main(String[] args) {
   
      try{
   
         // 连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // 添加数据
         Future fo = mcc.set("renren", 900, "Free Education");

         // 输出执行 set 方法后的状态
         System.out.println("set status:" + fo.get());
            
         // 使用 get 方法获取数据
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 通过 gets 方法获取 CAS token(令牌)
         CASValue casValue = mcc.gets("renren");

         // 输出 CAS token(令牌) 值
         System.out.println("CAS token - " + casValue);

         // 尝试使用cas方法来更新数据
         CASResponse casresp = mcc.cas("renren", casValue.getCas(), 900, "Largest Tutorials-Library");
         
         // 输出 CAS 响应信息
         System.out.println("CAS Response - " + casresp);

         // 输出值
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex)
         System.out.println(ex.getMessage());
   }
}

get 操作实例

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

import net.spy.memcached.MemcachedClient;

public class MemcachedJava {
   public static void main(String[] args) {
   
      try{
   
         // 连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // 添加数据
         Future fo = mcc.set("renren", 900, "Free Education");

         // 输出执行 set 方法后的状态
         System.out.println("set status:" + fo.get());

         // 使用 get 方法获取数据
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex)
         System.out.println(ex.getMessage());
   }
}

gets 操作实例、CAS

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

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

public class MemcachedJava {
   public static void main(String[] args) {
   
      try{
   
         // 连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // 添加数据
         Future fo = mcc.set("renren", 900, "Free Education");

         // 输出执行 set 方法后的状态
         System.out.println("set status:" + fo.get());
            
         // 从缓存中获取键为 renren 的值
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 通过 gets 方法获取 CAS token(令牌)
         CASValue casValue = mcc.gets("renren");

         // 输出 CAS token(令牌) 值
         System.out.println("CAS value in cache - " + casValue);

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex)
         System.out.println(ex.getMessage());
   }
}

delete 操作实例

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

import net.spy.memcached.MemcachedClient;

public class MemcachedJava {
   public static void main(String[] args) {
   
      try{
   
         // 连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // 添加数据
         Future fo = mcc.set("renren", 900, "World's largest online tutorials library");

         // 输出执行 set 方法后的状态
         System.out.println("set status:" + fo.get());

         // 获取键对应的值
         System.out.println("renren value in cache - " + mcc.get("renren"));

         // 对存在的key进行数据添加操作
         Future fo = mcc.delete("renren");

         // 输出执行 delete 方法后的状态
         System.out.println("delete status:" + fo.get());

         // 获取键对应的值
         System.out.println("renren value in cache - " + mcc.get("codingground"));

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex)
         System.out.println(ex.getMessage());
   }
}

Incr/Decr 操作实例

import java.net.InetSocketAddress;
import java.util.concurrent.Future;

import net.spy.memcached.MemcachedClient;

public class MemcachedJava {
   public static void main(String[] args) {
   
      try{
   
         // 连接本地的 Memcached 服务
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // 添加数字值
         Future fo = mcc.set("number", 900, "1000");

         // 输出执行 set 方法后的状态
         System.out.println("set status:" + fo.get());

         // 获取键对应的值
         System.out.println("value in cache - " + mcc.get("number"));

         // 自增并输出
         System.out.println("value in cache after increment - " + mcc.incr("number", 111));

         // 自减并输出
         System.out.println("value in cache after decrement - " + mcc.decr("number", 112));

         // 关闭连接
         mcc.shutdown();
         
      }catch(Exception ex)
         System.out.println(ex.getMessage());
   }
}