多線程注入失敗 空指針異常

寫在開始

起因是項目需要啟動一個多線程服務往RabbitMq灌入數據，當啟動多線程以@Autowired注解形式注入RabbitMq服務時發現NPE(空指針異常)。

首先排查RabbitMq是否注入成功，結果在Application中成功注入RabbitMq。調查后發現多線程類是無法通過注解方式直接獲取容器中內容的，

 

方案

將Application中獲取的句柄放入線程的構造函數中，搞定~~

通過下面兩種方案中的一種獲取注入到容器中的內容,前提是該項目為spring-boot項目

1注解方式

2應用上下文方式

 

代碼片段

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();
        // 應用上下文方式
        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:批量寫入數據到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();
            }
        }
    }
}