分布式事务 （定时任务 + 事件表 + MQ）实现小例子

业务流程图：

Controller 模拟接收请求 生成 100条数据 插入事件表：

   
   @RequestMapping("/producerMq")
    public @ResponseBody String mq() throws Exception {

        for(int i = 0;i<100;i++){
        
            Long userId = SnowFlake.nextId();//雪花算法生成id
            AopExsInfo aopExsInfo = new AopExsInfo();
            aopExsInfo.setId(userId);
            aopExsInfo.setType("new"); //状态对应为  新建
            int Anum = aopExsInfoMapper.insert(aopExsInfo); //插入事件表
//            System.out.println("新增结果： "+Anum);
        }
        return "新增完成";
    }

服务A：

package com...service_RabbitMQ;

import com.alibaba.fastjson.JSONObject;
import com...entity.AopExsInfo;
import com...mapper.AopExsInfoMapper;
import org.springframework.amqp.core.AmqpTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.Transactional;
import javax.annotation.PostConstruct;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

@Component
public class SendMqService {

    @Autowired
    AopExsInfoMapper aopExsInfoMapper;

    @Autowired
    private AmqpTemplate template;
    
    //项目启动自动循环执行
    //无论哪一步出异常都全部回滚，不影响数据一致性
    @PostConstruct
    @Transactional(rollbackFor = Exception.class)
    public void sendData(){

        System.out.println("开始扫描未推送的办件....");

        ScheduledExecutorService executor = Executors.newScheduledThreadPool(2);

        executor.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {

                //查出新增的数据 
                List<AopExsInfo> list = aopExsInfoMapper.selectNew("new");

                for (AopExsInfo aopExsInfo : list){

                    //先改事件表数据状态
                    AopExsInfo old = new AopExsInfo();
                    old = aopExsInfo;
                    old.setCupSize("old"); //对应为 已发送
                    int i = aopExsInfoMapper.updateByPrimaryKey(old);
//                    System.out.println("更改事件表状态返回： "+i);

                    //开始往MQ里推送
                    JSONObject json = new JSONObject();
                    json.put("id",aopExsInfo.getId());
                    json.put("cupSize",aopExsInfo.getCupSize());
//                    System.out.println("未推送的办件信息 ： "+json.toString());

                    template.convertAndSend(RabbitConstant.QUEUE_HELLOWORLD,json.toString());

                }
            }
        },0,10, TimeUnit.SECONDS);  //每10秒 查询推送 一次
    }
}

服务B：

package com...service_RabbitMQ;

import com.alibaba.fastjson.JSONObject;
import com.rabbitmq.client.Channel;
import com...entity.XueHuaInfo;
import com...mapper.XueHuaInfoMapper;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.amqp.rabbit.listener.api.ChannelAwareMessageListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.Transactional;
import javax.annotation.PostConstruct;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

@Component
public class AcceptMqService{

    @Autowired
    XueHuaInfoMapper xueHuaInfoMapper;

    //从MQ读取数据，插入事件表
   @RabbitListener(queues = RabbitConstant.QUEUE_HELLOWORLD)
   public void acceptData(String info, Channel channel, Message message){

       try {
           //手动 ACK
//           channel.basicAck(message.getMessageProperties().getDeliveryTag(),false);
           System.out.println("监听到的数据： "+info);
//           System.out.println("message : " +message);
           JSONObject JSON = JSONObject.parseObject(info);
           XueHuaInfo xueHuaInfo = new XueHuaInfo();
           xueHuaInfo.setId(JSON.getString("id")); //根据数据库主键唯一保证幂等性
           xueHuaInfo.setName("start"); //对应状态为 已接受
           xueHuaInfoMapper.insert(xueHuaInfo);

       } catch (Exception e) {
           e.getMessage();
       }
   }

    //项目启动自动执行
   @PostConstruct
   @Transactional(rollbackFor = Exception.class)
    public void updataData(){

       System.out.println("开始执行本地业务....");

       ScheduledExecutorService Service = Executors.newScheduledThreadPool(2);

       Service.scheduleAtFixedRate(new Runnable() {
           @Override
           public void run() {

                //查出新增的数据
               List<XueHuaInfo> infos = xueHuaInfoMapper.selectNew("start");

               System.out.println("本次读取办数量： "+infos.size());
               for(XueHuaInfo info : infos){

                //业务处理 省略....

                   XueHuaInfo endInfo = info;
                   endInfo.setName("end");//对应状态为 已处理
                   xueHuaInfoMapper.updateEnd(endInfo);
               }
           }
       },0,10, TimeUnit.SECONDS); ////每10秒查询一次
   }
}