我使用的是在数据库添加一个版本字段，记录版本，保证版本一致性，就能保证每次读取的是需要的内容。
具体问题：使用消息队列时，发送方给接收方发送消息，接收方修改了数据库的同时发送方查询数据库，由于是异步操作，会导致发送方读取的数据是修改前的数据，导致数据不一致的问题。
代码：
发送方
// 创建查询条件QueryWrapper<QuestionTest> queryWrapper = new QueryWrapper<>();queryWrapper.eq("userId", loginUser.getId()).eq("questionId", questionId);
// 查询是否存在记录QuestionTest existingRecord = questionTestMapper.selectOne(queryWrapper);插入一条新记录existingRecord.setQuestionId(questionId);existingRecord.setUserId(loginUser.getId());if (existingRecord.getId() == null) {existingRecord.setVersion(Long.valueOf(0));questionTestMapper.insert(existingRecord);}Long id = existingRecord.getId(); // 获取新插入记录的idLong version = existingRecord.getVersion();existingRecord.setVersion(version);Map<String, Object> taskMessage = new HashMap<>();taskMessage.put("id", id);taskMessage.put("questionId", questionId);taskMessage.put("userId", loginUser.getId());taskMessage.put("codeLanguage", questionSubmitAddRequest.getCodeLanguage());taskMessage.put("userCode", questionSubmitAddRequest.getUserCode());taskMessage.put("input", questionSubmitAddRequest.getUserJudgeCase().getInput());taskMessage.put("answer", question.getAnswer());taskMessage.put("version", version);
// System.out.println(taskMessage);String message = JSONUtil.toJsonStr(taskMessage);
// System.out.println(message);myMessageProducer.sendMessage("code_exchange", "my_routingKey_test", message);// 等待接收方处理完毕
// Long newVersion = null;while (!existingRecord.getVersion().equals(version + 1)) {existingRecord = questionTestMapper.selectById(id);}return existingRecord;接收方：
Map<String, Object> taskMessage = JSONUtil.toBean(message, Map.class);Long questionId = Long.valueOf(taskMessage.get("questionId") != null ? String.valueOf(taskMessage.get("questionId")) : "0");Long id = Long.valueOf(taskMessage.get("id") != null ? String.valueOf(taskMessage.get("id")) : "0");Long userId = Long.valueOf(taskMessage.get("userId") != null ? String.valueOf(taskMessage.get("userId")) : "0");String codeLanguage = String.valueOf(taskMessage.get("codeLanguage"));String userCode = String.valueOf(taskMessage.get("userCode"));String input = String.valueOf(taskMessage.get("input"));String answer = String.valueOf(taskMessage.get("answer"));Long version = Long.valueOf(taskMessage.get("version") != null ? String.valueOf(taskMessage.get("version")) : "0");
// System.out.println(answer);// 使用正确代码生成预期结果String output = judgeService.dojudgeTestCode(answer, input, codeLanguage);// 使用用户代码生成实际结果String predicted = judgeService.dojudgeTestCode(userCode, input, codeLanguage);JudgeCase currentJudgeCase = new JudgeCase();currentJudgeCase.setInput(input);currentJudgeCase.setOutput(output);JudgeCase userJudgeCase = new JudgeCase();userJudgeCase.setInput(input);userJudgeCase.setOutput(predicted);log.info("测试任务处理成功，Id = {}", id);// 5. 将结果存储到数据库或缓存中// 修保存到数据库中的测试结果version = version + 1;QuestionTest questionTest = new QuestionTest();questionTest.setVersion(version);questionTest.setId(id);questionTest.setQuestionId(questionId);questionTest.setUserId(userId);questionTest.setUserCode(userCode);questionTest.setCodeLanguage(codeLanguage);questionTest.setCurrentJudgeCase(JSONUtil.toJsonStr(currentJudgeCase));questionTest.setUserJudgeCase(JSONUtil.toJsonStr(userJudgeCase));
// System.out.println("QuestionTest:"+questionTest);questionFeignClient.updateQuestionTestById(questionTest);// 6. 手动确认消息channel.basicAck(deliveryTag, false);