Memcached 简明教程

Memcached - Delete Key

Memcached delete 命令用于从 Memcached 服务器中删除现有密钥。

Syntax

Memcached delete 命令的基本语法如下所示：

delete key [noreply]

Output

CAS 命令可能生成以下结果之一：

DELETED indicates successful deletion.
ERROR 表示在删除数据或语法错误时出现错误。
NOT_FOUND 指示密钥不存在于 Memcached 服务器中。

Example

在此示例中，我们使用 tutorialspoint 作为密钥，并将 memcached 存储在其中，其到期时间为 900 秒。此后，它将删除存储的密钥。

set tutorialspoint 0 900 9
memcached
STORED
get tutorialspoint
VALUE tutorialspoint 0 9
memcached
END
delete tutorialspoint
DELETED
get tutorialspoint
END
delete tutorialspoint
NOT_FOUND

Delete Data Using Java Application

若要从 Memcached 服务器删除数据，您需要使用 Memcached delete 方法。

Example

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

import net.spy.memcached.MemcachedClient;

public class MemcachedJava {
   public static void main(String[] args) {

      try{

         // Connecting to Memcached server on localhost
         MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211));
         System.out.println("Connection to server sucessful.");

         // add data to memcached server
         Future fo = mcc.set("tutorialspoint", 900, "World's largest online tutorials library");

         // print status of set method
         System.out.println("set status:" + fo.get());

         // retrieve and check the value from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("tutorialspoint"));

         // try to add data with existing key
         Future fo = mcc.delete("tutorialspoint");

         // print status of delete method
         System.out.println("delete status:" + fo.get());

         // retrieve and check the value from cache
         System.out.println("tutorialspoint value in cache - " + mcc.get("codingground"));

         // Shutdowns the memcached client
         mcc.shutdown();

      }catch(Exception ex)
         System.out.println(ex.getMessage());
   }
}

Output

编译并执行该程序后，您可以看到以下输出：

Connection to server successful
set status:true
tutorialspoint value in cache - World's largest online tutorials library
delete status:true
tutorialspoint value in cache - null