private String getProjectIds(List<String> projectIdList ) { String projectIds = "("; for (String projectId : projectIdList) { projectIds += "," + projectId; } projectIds += ")"; return projectIds; }请优化此方法

在这个方法中，字符串 `projectIds` 被频繁地修改，这会带来性能问题，可以使用 `StringBuilder` 来代替字符串拼接。同时，可以使用 Java 8 的 `String.join()` 方法来简化代码。修改后的代码如下所示：

private String getProjectIds(List<String> projectIdList) {
    StringBuilder sb = new StringBuilder("(");
    sb.append(String.join(",", projectIdList));
    sb.append(")");
    return sb.toString();
}

这样就避免了频繁的字符串拼接操作，提高了性能。

相关问题

调用“@Resource private ApplicationServicePlatformClientProxy applicationServicePlatformClientProxy;”获取“projectName"修改下面代码： @Override public List<ProjectCountVO> projectCount(String beginTime, String endTime, Integer forceType, String projectId) { 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); //查询项目名称 String projectName = Optional.ofNullable(projectTaskMap.get(projectId)).map(taskList -> taskList.get(0).getName()).orElse(""); 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; }

您需要将代码中的“projectName”替换为您要使用的变量名称，例如“name”：

@Resource 
private ApplicationServicePlatformClientProxy applicationServicePlatformClientProxy;

@Override 
public List<ProjectCountVO> projectCount(String beginTime, String endTime, Integer forceType, String projectId) { 
  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); 
    //查询项目名称 
    String name = Optional.ofNullable(projectTaskMap.get(projectId)).map(taskList -> taskList.get(0).getName()).orElse(""); 
    projectCountVO.setName(name); 
    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; 
}

优化代码：@Override public List<ProjectCountVO> projectCount(String beginTime, String endTime, Integer forceType, String projectId) { 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()) { String currentProjectId = projectTaskEntry.getKey(); ProjectCountVO projectCountVO = new ProjectCountVO(); projectCountVO.setId(currentProjectId); // 查询项目名称 ProjectCondition queryProjectDto = new ProjectCondition(); queryProjectDto.setCompanyId(companyId); queryProjectDto.setDesignStatusList(designStatusList); queryProjectDto.setPageSize(pageSize); queryProjectDto.setUserId(userId); ResultWrapper<QueryAllProject> queryAllProjectResult = applicationServicePlatformClient.listUserProject(bspToken, bspUserId, bspUserEnvId, bspUserTenant, queryProjectDto); QueryAllProject queryAllProject = queryAllProjectResult.getData(); projectCountVO.setName(queryAllProject.getProjectName()); 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; }

可以考虑对代码进行以下优化：

1. 将查询项目名称的逻辑提取成一个方法，避免在循环中重复查询。

2. 使用lambda表达式简化代码，如使用`stream().mapToInt().sum()`代替`stream().collect(Collectors.summingInt())`。

3. 对于空集合的判断，可以使用`Optional.ofNullable().orElse()`代替`CollectionUtil.isEmpty()`。

优化后的代码如下：

@Override
public List<ProjectCountVO> projectCount(String beginTime, String endTime, Integer forceType, String projectId) {
    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()) {
        String currentProjectId = projectTaskEntry.getKey();
        ProjectCountVO projectCountVO = new ProjectCountVO();
        projectCountVO.setId(currentProjectId);
        projectCountVO.setName(queryProjectName(currentProjectId)); // 查询项目名称
        List<TaskTask> taskList = projectTaskEntry.getValue();
        projectCountVO.setTaskCount(taskList.size());
        Integer problemCount = taskList.stream()
                .mapToInt(task -> Optional.ofNullable(task.getProblemNum()).orElse(0))
                .sum();
        projectCountVO.setProblemCount(problemCount);
        result.add(projectCountVO);
    }

    return result;
}

/**
 * 查询项目名称
 */
private String queryProjectName(String projectId) {
    ProjectCondition queryProjectDto = new ProjectCondition();
    queryProjectDto.setCompanyId(companyId);
    queryProjectDto.setDesignStatusList(designStatusList);
    queryProjectDto.setPageSize(pageSize);
    queryProjectDto.setUserId(userId);
    ResultWrapper<QueryAllProject> queryAllProjectResult = applicationServicePlatformClient.listUserProject(bspToken, bspUserId, bspUserEnvId, bspUserTenant, queryProjectDto);
    QueryAllProject queryAllProject = queryAllProjectResult.getData();
    return queryAllProject.getProjectName();
}