List<IotUser> iotUserList = iotUserMapper.getIotUserList(null, null); Map<String, Map<Integer, List<IotUser>>> collect = iotUserList.stream().collect(Collectors.groupingBy(IotUser::getUserMobile, Collectors.groupingBy(IotUser::getUserType))); List<IotUser> result = null; collect.forEach((k,v)->{ v.forEach((a,b)->{ List<String> collect1 = b.stream().map(IotUser::getOrgUid).collect(Collectors.toList()); String collect2 = collect1.stream().collect(Collectors.joining(",")); IotUser iotUser = b.get(0); result.add(iotUser); }); });这段代码的解释及如何优化

这段代码是对一个 List<IotUser> 进行分组，按照用户手机号和用户类型进行分组，然后将每组中的机构 ID 拼接成一个字符串，最后将每组中的第一个元素添加到结果列表中。

为了优化这段代码，可以考虑使用并行流来提高效率，同时可以使用 ConcurrentHashMap 来替代普通的 HashMap，以提高并发性能。另外，在对每组进行操作时，可以使用 reduce 方法来避免创建中间集合，从而减少内存开销。

相关问题

优化代码：public List<ProjectCountVO> projectCount(String beginTime, String endTime, Integer forceType, String projectId) { ResultWrapper<QueryAllProjectName> resultWrapper = (ResultWrapper<QueryAllProjectName>) applicationServicePlatformClient.queryProjectName(projectId); if (resultWrapper.getData() == null) { return Collections.emptyList(); } String projectName = resultWrapper.getData().getProjectName(); List<TaskTask> taskTaskList = this.listStatisticsTask(beginTime, endTime, forceType, projectId); if (CollectionUtil.isEmpty(taskTaskList)) { return Collections.emptyList(); } List<ProjectCountVO> result = new ArrayList<>(); Map<String, List<TaskTask>> projectTaskMap = taskTaskList.stream().collect(Collectors.groupingBy(TaskTask::getProjectId)); for (Map.Entry<String, List<TaskTask>> projectTaskEntry : projectTaskMap.entrySet()) { projectId = projectTaskEntry.getKey(); ProjectCountVO projectCountVO = new ProjectCountVO(); projectCountVO.setId(projectId); projectCountVO.setName(projectName); List<TaskTask> taskList = projectTaskEntry.getValue(); projectCountVO.setTaskCount(taskList.size()); Integer problemCount = CollectionUtil.isEmpty(taskList) ? 0 : taskList.stream().collect(Collectors.summingInt(task -> Optional.ofNullable(task.getProblemNum()).orElse(0))); projectCountVO.setProblemCount(problemCount); result.add(projectCountVO); } return result; }

可以尝试以下优化：

1. 使用 Optional 类简化代码。可以使用 `Optional.ofNullable()` 来避免空指针异常，使用 `orElse()` 来指定默认值。

2. 使用 Stream API 来简化代码。可以使用 `Collectors.groupingBy()` 来对列表进行分组，使用 `Collectors.summingInt()` 来统计数量。

3. 减少方法调用次数。可以将 `resultWrapper.getData()` 的结果保存在变量中，避免多次调用。

4. 将变量名命名得更具有表现力。可以将 `taskTaskList` 改为 `tasks`，将 `projectTaskMap` 改为 `projectTasks`。

优化后的代码如下：

public List<ProjectCountVO> projectCount(String beginTime, String endTime, Integer forceType, String projectId) {
    ResultWrapper<QueryAllProjectName> resultWrapper = (ResultWrapper<QueryAllProjectName>) applicationServicePlatformClient.queryProjectName(projectId);
    QueryAllProjectName projectNameData = resultWrapper.getData();
    if (projectNameData == null) {
        return Collections.emptyList();
    }
    String projectName = projectNameData.getProjectName();

    List<TaskTask> tasks = this.listStatisticsTask(beginTime, endTime, forceType, projectId);
    if (CollectionUtil.isEmpty(tasks)) {
        return Collections.emptyList();
    }

    Map<String, List<TaskTask>> projectTasks = tasks.stream().collect(Collectors.groupingBy(TaskTask::getProjectId));

    List<ProjectCountVO> result = new ArrayList<>();
    for (Map.Entry<String, List<TaskTask>> projectTaskEntry : projectTasks.entrySet()) {
        String projectTaskId = projectTaskEntry.getKey();

        ProjectCountVO projectCountVO = new ProjectCountVO();
        projectCountVO.setId(projectTaskId);
        projectCountVO.setName(projectName);

        List<TaskTask> taskList = projectTaskEntry.getValue();
        projectCountVO.setTaskCount(taskList.size());

        Integer problemCount = taskList.stream()
                .map(TaskTask::getProblemNum)
                .filter(Objects::nonNull)
                .mapToInt(Integer::intValue)
                .sum();
        projectCountVO.setProblemCount(problemCount);

        result.add(projectCountVO);
    }

    return result;
}

优化这段java代码 //通过域账号名称 调用userSdk获取 对应ID List<String> sendUserNameList = form.getOperationScoreDTOList() .stream().map(OperationScoreDTO::getSenderName).distinct().collect(Collectors.toList()); List<String> receiverUserNameList = form.getOperationScoreDTOList() .stream().map(OperationScoreDTO::getReceiverName).distinct().collect(Collectors.toList()); List<FindOneByUsernameVo> sendUserList = userServiceSdk.findByUsernames(sendUserNameList); List<FindOneByUsernameVo> receiverUserList = userServiceSdk.findByUsernames(receiverUserNameList); Map<String, Integer> senderMap = sendUserList .stream() .collect(Collectors.toMap(FindOneByUsernameVo::getUsername, FindOneByUsernameVo::getTeclibUserId)); Map<String, Integer> receiverMap = receiverUserList .stream() .collect(Collectors.toMap(FindOneByUsernameVo::getUsername, FindOneByUsernameVo::getTeclibUserId)); for (OperationScoreDTO operationScoreDTO : form.getOperationScoreDTOList()) { Integer senderId = senderMap.get(operationScoreDTO.getSenderName()); if (senderId == null) { throw new BizException("获取发送者失败"); } Integer receiverId = receiverMap.get(operationScoreDTO.getSenderName()); if (receiverId == null) { throw new BizException("获取接收者失败"); } Short score = operationScoreDTO.getScore(); String remark = operationScoreDTO.getRemark(); OperationScoreEntity os = new OperationScoreEntity(); os.setSendId(senderId); os.setReceiverId(receiverId); os.setEvent(score.toString()); os.setRemark(remark); os.setSendTime(LocalDate.now()); operationScoreRepository.save(os); String event = ScoreEventConstant.BONUS_SCORE; String module = ScoreModuleConstant.BONUS_SCORE; String payload = String.format("osId:%d;receiver:%d;remark:%s;score:%s", os.getId(), receiverId, remark, score); UserScoreEntity userScore = new UserScoreEntity(); userScore.setUserId(receiverId); userScore.setModule(module); userScore.setEvent(event); userScore.setPayload(payload); userScore.setOperationTime(operationScoreDTO.getOperationTime()); userScore.setScore(score); Integer totalScore = this.findTotalScoreByUserId(receiverId); userScore.setTotal(Math.max(totalScore + score, 0)); userScoreRepository.save(userScore); } return Boolean.TRUE;

在这段代码中，你可以考虑以下优化措施：

1. 将重复的代码提取为方法：将获取用户名列表和调用 `userServiceSdk.findByUsernames` 的逻辑提取为一个方法，这样可以减少重复代码。

2. 使用 `forEach` 替代 `for` 循环：使用流的 `forEach` 方法可以简化循环的书写，更加简洁和直观。

3. 使用批量插入：使用批量插入操作可以减少数据库交互次数，提高性能。

下面是优化后的代码示例：

List<String> sendUserNameList = form.getOperationScoreDTOList()
    .stream().map(OperationScoreDTO::getSenderName).distinct().collect(Collectors.toList());
List<String> receiverUserNameList = form.getOperationScoreDTOList()
    .stream().map(OperationScoreDTO::getReceiverName).distinct().collect(Collectors.toList());

Map<String, Integer> senderMap = getUserIdsByUsernames(sendUserNameList);
Map<String, Integer> receiverMap = getUserIdsByUsernames(receiverUserNameList);

form.getOperationScoreDTOList().forEach(operationScoreDTO -> {
    Integer senderId = senderMap.get(operationScoreDTO.getSenderName());
    if (senderId == null) {
        throw new BizException("获取发送者失败");
    }
    Integer receiverId = receiverMap.get(operationScoreDTO.getSenderName());
    if (receiverId == null) {
        throw new BizException("获取接收者失败");
    }
    Short score = operationScoreDTO.getScore();
    String remark = operationScoreDTO.getRemark();

    OperationScoreEntity os = new OperationScoreEntity();
    os.setSendId(senderId);
    os.setReceiverId(receiverId);
    os.setEvent(score.toString());
    os.setRemark(remark);
    os.setSendTime(LocalDate.now());
    operationScoreRepository.save(os);

    String event = ScoreEventConstant.BONUS_SCORE;
    String module = ScoreModuleConstant.BONUS_SCORE;
    String payload = String.format("osId:%d;receiver:%d;remark:%s;score:%s",
            os.getId(), receiverId, remark, score);

    UserScoreEntity userScore = new UserScoreEntity();
    userScore.setUserId(receiverId);
    userScore.setModule(module);
    userScore.setEvent(event);
    userScore.setPayload(payload);
    userScore.setOperationTime(operationScoreDTO.getOperationTime());
    userScore.setScore(score);
    Integer totalScore = this.findTotalScoreByUserId(receiverId);
    userScore.setTotal(Math.max(totalScore + score, 0));

    userScoreRepository.save(userScore);
});

return Boolean.TRUE;

private Map<String, Integer> getUserIdsByUsernames(List<String> usernames) {
    List<FindOneByUsernameVo> userList = userServiceSdk.findByUsernames(usernames);
    return userList.stream()
        .collect(Collectors.toMap(FindOneByUsernameVo::getUsername, FindOneByUsernameVo::getTeclibUserId));
}

通过上述优化，你可以减少代码重复，提高代码的可读性和维护性，并且减少数据库交互次数，提高性能。