概述

RocketMQ-初体验RocketMQ(10)-过滤消息_SQL92表达式筛选消息通过SQL92的方式，消费者可以过滤到自己想要的消息，其实RocketMQ还提供了一个更为抢到的功能，支持自定义Java类…

直接来看下如何使用的吧

集群信息

RocketMQ ： V4.3.2

集群模式：互为主备

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节点信息： 192.168.18.130 192.168.18.131 双机互为主备

broker-m.conf 和 broker-s.conf 均已配置了 filterServerNums=1 ，已重启。

项目结构

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生产者

package com.artisan.rocketmq.filter;

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.common.message.Message;
import org.apache.rocketmq.remoting.common.RemotingHelper;

/**
 * @author 小工匠
 * @version v1.0
 * @create 2019-11-11 23:30
 * @motto show me the code ,change the word
 * @blog https://artisan.blog.csdn.net/
 * @description
 **/
public class FilterProducer {


    /***
     * TAG-FILTER-1000 ---> 布隆过滤器
     * 过滤掉的那些消息。直接就跳过了么。下次就不会继续过滤这些了。是么。
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        DefaultMQProducer producer = new DefaultMQProducer("filter_sample_group");
        producer.setNamesrvAddr("192.168.18.130:9876;192.168.18.131:9876");
        producer.start();

        for (int i = 0; i < 3; i++) {
            Message msg = new Message("TopicFilter",
                    "TAG-FILTER",
                    ("Hello RocketMQ " + i).getBytes(RemotingHelper.DEFAULT_CHARSET)
            );

            // Set some properties. 生产者设置属性，消费者端通过Tag+该属性定制消息
            msg.putUserProperty("a", String.valueOf(i));
            if (i % 2 == 0) {
                msg.putUserProperty("b", "artisan");
            } else {
                msg.putUserProperty("b", "smart artisan");
            }
            producer.send(msg);
        }

        producer.shutdown();
    }

}

自定义类

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.artisan.rocketmq.filter;

import org.apache.rocketmq.common.filter.FilterContext;
import org.apache.rocketmq.common.filter.MessageFilter;
import org.apache.rocketmq.common.message.MessageExt;

public class MessageFilterImpl implements MessageFilter {

    @Override
    public boolean match(MessageExt msg, FilterContext context) {
        String property = msg.getProperty("SequenceId");
        if (property != null) {
            int id = Integer.parseInt(property);
            if (((id % 10) == 0) && (id > 100)) {
                return true;
            }
        }
        return false;
    }
}

消费者

package com.artisan.rocketmq.filter;

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.MessageSelector;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.common.message.MessageExt;
import org.apache.rocketmq.remoting.common.RemotingHelper;

import java.io.UnsupportedEncodingException;
import java.util.List;

/**
 * @author 小工匠
 * @version v1.0
 * @create 2019-11-11 23:45
 * @motto show me the code ,change the word
 * @blog https://artisan.blog.csdn.net/
 * @description
 **/
public class FilterConsumer {

    public static void main(String[] args) throws Exception {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("filter_sample_group");
        /**
         * 注册中心
         */
        consumer.setNamesrvAddr("192.168.18.130:9876;192.168.18.131:9876");
        /**
         * 订阅主题
         * 一种资源去换取另外一种资源
         */
        consumer.subscribe("TopicFilter", MessageSelector.bySql("a between 0 and 3 and b = 'artisan'"));
        /**
         * 注册监听器，监听主题消息
         */
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs,
                                                            ConsumeConcurrentlyContext context) {
                for (MessageExt msg : msgs){
                    try {
                        System.out.println("consumeThread=" + Thread.currentThread().getName()
                                + ", queueId=" + msg.getQueueId() + ", content:"
                                + new String(msg.getBody(), RemotingHelper.DEFAULT_CHARSET));
                    } catch (UnsupportedEncodingException e) {
                        e.printStackTrace();
                    }
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        consumer.start();

        System.out.printf("Filter Consumer Started.%n");
    }
}