spring boot ApplicationRunner使用

spring boot ApplicationRunner使用

它的使用比较简单，实现ApplicationRunner的run方法

package com.hikvision.pbg.jc.confuciussecurity.modules.task;

import com.hikvision.pbg.jc.confuciussecurity.modules.constant.Constant;
import com.hikvision.pbg.jc.confuciussecurity.modules.util.kafka.KafkaProducerPool;
import com.hikvision.pbg.jc.confuciussecurity.modules.util.kafka.StringUtil;
import kafka.javaapi.producer.Producer;
import kafka.producer.KeyedMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Component
@Order(1)
public class KafkaFaceProducerTest implements ApplicationRunner {
    private static Logger logger = LoggerFactory.getLogger(KafkaFaceProducerTest.class);
    Producer<String, String> producer = KafkaProducerPool.getInstance(Constant.KAFKA_ADDR);
    public KafkaFaceProducerTest(){

    }
    @Override
    public void run(ApplicationArguments applicationArguments) throws Exception {

        while(true){
            Thread.sleep(1000);
            logger.info("kafka produce message");
            try {
                String str =String.valueOf(System.currentTimeMillis());
                producer.send(new KeyedMessage<String, String>("JSON_TOPIC", StringUtil.getUUID(), str));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        //Thread.sleep(5000);
        //Producer<String, String> producer = KafkaProducerPool.getInstance(Constant.KAFKA_ADDR);

    }
}

它什么时候使用

一般我们spring boot 启动类这么写

    public static void main(String[] args) {
        System.out.println("begin1");
        SpringApplication.run(XX.class, args);
        System.out.println("begin2");
    }

ApplicationRunner的使用就在SpringApplication.run，里面有一段这样的代码实现就是：先把ApplicationRunner list执行完，再接着执行SpringApplication.run方法。

如果想通过先把ApplicationRunner起一个task，如果死循环，就很危险！因为main方法也进入到了死循环的阶段

    private void callRunners(ApplicationContext context, ApplicationArguments args) {
        List<Object> runners = new ArrayList();
        runners.addAll(context.getBeansOfType(ApplicationRunner.class).values());
        runners.addAll(context.getBeansOfType(CommandLineRunner.class).values());
        AnnotationAwareOrderComparator.sort(runners);
        Iterator var4 = (new LinkedHashSet(runners)).iterator();

        while(var4.hasNext()) {
            Object runner = var4.next();
            if (runner instanceof ApplicationRunner) {
                this.callRunner((ApplicationRunner)runner, args);
            }

            if (runner instanceof CommandLineRunner) {
                this.callRunner((CommandLineRunner)runner, args);
            }
        }

    }