redis key过期通知

1、使用redis key 过期通知，需开启key过期通知功能：

登录进入redis-cli 客户端，执行：

 

config set notify-keyspace-events Ex

【或者启动redis前在redis.conf 添加配置：notify-keyspace-events "Ex" //过期时间监听生效】

2、启动监听key过期

登录进入redis-cli 客户端，执行：( 订阅一个或者多个符合pattern格式的频道)

PSUBSCRIBE __keyevent@*__:expired    

然后该客户端处于监听状态，如果有key过期，则列出

    Redis中发布与订阅只有简单的6个命令。即：
    
    订阅一个或者多个符合pattern格式的频道
    PSUBSCRIBE pattern [pattern ...]
    
    发布消息到chanel中
    PUBLISH channel message
    
    查看订阅与发布系统状态
    PUBSUB subcommand [argument [argument ...]]
    
    退订所有符合格式的频道
    PUNSUBSCRIBE [pattern [pattern ...]]
    
    订阅一个或者多个频道
    SUBSCRIBE channel [channel ...]
    
    取消订阅频道
    UNSUBSCRIBE [channel [channel ...]]

--------------------

测试：

3、另外开启一个客户端，添加test 为key，并设置5秒过期

setex test 5 test

5秒后，监听窗口显示：

 pmessage

__keyevent@*__:expired

__keyevent@0__:expired

test

 

java 代码：

 

 

先测试一下发布订阅

1、订阅消息的类

import redis.clients.jedis.JedisPubSub;

//订阅消息的处理类
public class SubScriber  extends JedisPubSub {
 
    @Override  //收到消息会调用
    public void onMessage(String channel, String message) {
        System.out.println(String.format("收到消息: channel %s, message %s", channel, message));
    }

    @Override  //订阅了频道会调用
    public void onSubscribe(String channel, int subscribedChannels) {
        System.out.println(String.format("订阅了频道: channel %s, subscribedChannels %d",
                channel, subscribedChannels));
    }

    @Override  //取消订阅 会调用
    public void onUnsubscribe(String channel, int subscribedChannels) {
        System.out.println(String.format("取消订阅: channel %s, subscribedChannels %d",
                channel, subscribedChannels));
    }

    @Override
    public void onPSubscribe(String pattern, int subscribedChannels) {
        System.out.println("on PSubscribe " + pattern + " " + subscribedChannels);
    }

    @Override  //收到消息会调用
    public void onPMessage(String pattern, String channel, String message) {
        System.out.println(
                "pattern = [" + pattern + "], channel = [" + channel + "], message = [" + message + "]");
        //收到消息 key的键值，处理过期提醒
    }
}

2、订阅mychannel

private final Subscriber subscriber = new Subscriber();

jedis.subscribe(subscriber, "mychannel");    //订阅mychannel, 订阅后当前线程处于租塞状态，等等消息

3、在 mychannel 的频道上推送消息

jedis.publish("mychannel","abc");   //在 mychannel 的频道上推送消息

测试

    public static void main(String[] args) throws InterruptedException {

        Jediss jedis = Redis.getUserJedis();

        PubSubScriber subscriber = new PubSubScriber();


        Thread t = new Thread(new Runnable() {
            public void run() {
                for (int i = 0; i < 10; i++) {
                    try {
                        Thread.currentThread().sleep(3000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    jedis.publish("mychannel", "abc - " + i); //在 mychannel 的频道上推送消息 
                }
            }
        });
        t.start();


        jedis.subscribe(subscriber, "mychannel"); // 订阅mychannel, 订阅后当前线程处于租塞状态，等等消息

    }

 结果：

订阅了频道: channel mychannel, subscribedChannels 1
收到消息: channel mychannel, message abc - 0
收到消息: channel mychannel, message abc - 1

 

 

4、订阅键的过期时间的键值

__keyevent@0__:expired

测试： （注意先 config set notify-keyspace-events Ex）

    //PSUBSCRIBE __keyevent@*__:expired
    public static void main(String[] args) throws InterruptedException {

        Jediss jedis = Redis.getUserJedis();

        PubSubScriber subscriber = new PubSubScriber();


        Thread t = new Thread(new Runnable() {
            public void run() {
                for (int i = 0; i < 10; i++) {
                    try {
                        Thread.currentThread().sleep(3000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    jedis.setex("test:ex:"+i,3,"abc"); //3秒过期
                    System.out.println("test:ex:"+i);
                }
            }
        });
        t.start();


        jedis.psubscribe(subscriber, "__keyevent@*__:expired"); // 订阅 __keyevent@*__:expired, 订阅后当前线程处于租塞状态，等等消息
    }

 on PSubscribe __keyevent@*__:expired 1
test:ex:0
pattern = [__keyevent@*__:expired], channel = [__keyevent@1__:expired], message = [test:ex:0]
test:ex:1
test:ex:2
pattern = [__keyevent@*__:expired], channel = [__keyevent@1__:expired], message = [test:ex:1]
pattern = [__keyevent@*__:expired], channel = [__keyevent@1__:expired], message = [test:ex:2]

标签：__,订阅,keyevent,过期,pattern,redis,key,expired,channel
来源： https://blog.csdn.net/QQ2856639881/article/details/90725648