下面代码为何无法获取“projectname”：Map<String, String> projectMap = queryAllProject.stream().collect(Collectors.toMap(QueryAllProject::getId, QueryAllProject::getName)); // 遍历项目及对应的任务列表 for (Map.Entry<String, List<TaskTask>> projectTaskEntry : projectTaskMap.entrySet()) { projectId = projectTaskEntry.getKey(); ProjectCountVO projectCountVO = new ProjectCountVO(); projectCountVO.setId(projectId); // 根据projectId获取项目名称 String projectName = projectMap.get(projectId); projectCountVO.setName(projectName); //projectCondition.setProjectName(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;

可能是因为 `queryAllProject` 中没有包含 `projectid` 对应的值，导致在 `projectMap` 中无法找到对应的项目名称。你可以添加一个空值判断，如下所示：

String projectName = projectMap.get(projectId);
if (projectName == null) {
    projectName = "";
}
projectCountVO.setName(projectName);

这样就能够避免 `NullPointerException` 的出现，并将未找到项目名称的情况视为一个空字符串。