java 消费NSQ消息

使用监听器，来实现实时消费nsq的消息

一、目前spring boot中支持的事件类型如下

1. ApplicationFailedEvent：该事件为spring boot启动失败时的操作

2. ApplicationPreparedEvent：上下文context准备时触发

3. ApplicationReadyEvent：上下文已经准备完毕的时候触发

4. ApplicationStartedEvent：spring boot 启动监听类

5. SpringApplicationEvent：获取SpringApplication

6. ApplicationEnvironmentPreparedEvent：环境事先准备

二、这里我使用的是监听ApplicationReadyEvent事件，实现ApplicationListener<ApplicationReadyEvent>接口

package com.device.nsq.Receiver;

import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;import org.springframework.stereotype.Component;
import com.github.brainlag.nsq.NSQConsumer;
import com.github.brainlag.nsq.lookup.DefaultNSQLookup;
import com.github.brainlag.nsq.lookup.NSQLookup;

/**
 * nsq监听消息
 * 
 * @author joey
 *
 */
@Component
public class NsqMessageReceiver implements ApplicationListener<ApplicationReadyEvent> {
    private Logger logger = LoggerFactory.getLogger(NsqMessageReceiver.class);/**
     * 监听nsq消息
     */
    @Override
    public void onApplicationEvent(ApplicationReadyEvent event) {
        NSQLookup lookup = new DefaultNSQLookup();
        Executor executor = Executors.newFixedThreadPool(20);        lookup.addLookupAddress(127.0.0.1, 4150);// 监听topicname的topic
        NSQConsumer registerConsumer = new NSQConsumer(lookup, "topicname", "channel",
                (message) -> {
                    logger.info("收到消息:" + new String(message.getMessage()));
                    message.finished();
                });
        registerConsumer.setExecutor(executor);
        registerConsumer.start();
　　}
}

三、通过SpringApplication类中的addListeners方法将自定义的监听器注册进去

package com.device;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import com.device.nsq.Receiver.NsqMessageReceiver;

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication application = new SpringApplication(Application.class);
        application.addListeners(new NsqMessageReceiver());
        application.run(args);
    }
}

启动，向nsq的topicname发送消息，程序会自动进行消费

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