JAVA高级面试进阶训练营视频教程

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写在开始

起因是项目需要启动一个多线程服务往RabbitMq灌入数据，当启动多线程以@Autowired注解形式注入RabbitMq服务时发现NPE(空指针异常)。

首先排查RabbitMq是否注入成功，结果在Application中成功注入RabbitMq。调查后发现多线程类是无法通过注解方式直接获取容器中内容的，

 

方案

将Application中获取的句柄放入线程的构造函数中，搞定~~

通过下面两种方案中的一种获取注入到容器中的内容,前提是该项目为spring-boot项目

1注解方式

2应用上下文方式

 

代码片段

package com.navinfo.platform.rabbitmq;

import com.navinfo.platform.rabbitmq.configuration.RabbitMqConfiguration;
import com.navinfo.platform.rabbitmq.message.DefaultMessageChannel;
import com.navinfo.platform.rabbitmq.message.MessageChannel;
import com.navinfo.platform.rabbitmq.thread.PushToRabbitMQThread;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Import;

import javax.annotation.PostConstruct;

@SpringBootApplication
@ComponentScan("com.navinfo.platform.rabbitmq")
@Import({RabbitMqConfiguration.class})
public class LocationRabbitmqApplication {

    @Autowired
    private MessageChannel messageChannel;

    @Autowired
    private ApplicationContext applicationContext;

    public static void main(String[] args) {
        SpringApplication.run(LocationRabbitmqApplication.class, args);
    }

    @PostConstruct
    public void TestFun() {

        // 注解方式
        new PushToRabbitMQThread(messageChannel).start();
        // 应用上下文方式
        MessageChannel messageChannel2 = applicationContext.getBean(DefaultMessageChannel.class);
        new PushToRabbitMQThread(messageChannel2).start();
    }


}

 

package com.navinfo.platform.rabbitmq.thread;

import com.navinfo.platform.rabbitmq.command.TestCommand;
import com.navinfo.platform.rabbitmq.message.MessageChannel;

import java.util.UUID;

/**
 * @Description:批量写入数据到RabbitMQ
 * @Author:tianminghai
 * @Date:3:15 PM 2018/10/31
 */
public class PushToRabbitMQThread extends Thread {
    private MessageChannel messageChannel;

    public PushToRabbitMQThread(MessageChannel messageChannel) {
        this.messageChannel = messageChannel;
    }

    @Override
    public void run() {
        while (true) {

            TestCommand testCommand = new TestCommand();
            testCommand.setTestKey(UUID.randomUUID().toString());
            messageChannel.send("tianmh", testCommand);
            try {
                this.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}