Memcached incr 和 decr 命令用于递增或递减现有密钥的数值.如果找不到密钥,则返回 NOT_FOUND .如果键不是数字,则返回 CLIENT_ERROR不能递增或递减非数字值.否则,返回 ERROR .
Memcached的基本语法 incr 命令如下所示 :
incr key increment_value
在此示例中,我们使用访问者作为键并最初将其设置为10,此后我们将访问者增加5.
set visitors 0 900 2 10 STORED get visitors VALUE visitors 0 2 10 END incr visitors 5 15 get visitors VALUE visitors 0 2 15 END
Memcached decr 命令的基本语法如下所示
decr key decrement_value
set visitors 0 900 2 10 STORED get visitors VALUE visitors 0 2 10 END decr visitors 5 5 get visitors VALUE visitors 0 1 5 END
要在Memcached服务器中递增或递减数据,您需要分别使用Memcached incr或decr 方法.
import net.spy.memcached.MemcachedClient; public class MemcachedJava { public static void main(String[] args) { // Connecting to Memcached server on localhost MemcachedClient mcc = new MemcachedClient(new InetSocketAddress("127.0.0.1", 11211)); System.out.println("Connection to server sucessfully"); System.out.println("set status:"+mcc.set("count", 900, "5").isDone()); // Get value from cache System.out.println("Get from Cache:"+mcc.get("count")); // now increase the stored value System.out.println("Increment value:"+mcc.incr("count", 2)); // now decrease the stored value System.out.println("Decrement value:"+mcc.decr("count", 1)); // now get the final stored value System.out.println("Get from Cache:"+mcc.get("count")); } }
在编译和执行程序时,你会到达请参阅以下输出 :
Connection to server successfully set status:true Get from Cache:5 Increment value:7 Decrement value:6 Get from Cache:6