队列同步(Queue synchronization)

 我正在使用Java rabbitmq API。 这是我的应用程序的样子：  
 
 发布者A将作业发送到Q1 ，然后许多消费者B完成工作并创建新作业并将其发送到Q2 ，其中许多消费者C完成工作。 
 
 我想确保没有重复的作业发送到Q2 ，我该如何实现？ 
 
 请记住两种情况： 
 
 
 
 在将工作发送到Q2但在向Q1确认他已完成工作之前B崩溃 
 
 
 在向Q1发送确认但在将作业发送到Q2之前B崩溃 
 

I am working with Java rabbitmq API. This how my app looks like: 
 
Publisher A sends jobs to Q1, then many consumers B do the job and create new job and send it to Q2, where many consumer C do the job.
 
I want to make sure that no duplicated jobs are sent to Q2, how can I achieve this?
 
Take in mind two scenarios:
 
 
 
B crash after sending job to Q2 but before sending acknowledgment to Q1 that he completed the job
 
 
B crash after sending acknowledgment to Q1 but before sending job to Q2
 

原文：https://stackoverflow.com/questions/39445887