@RequestMapping("/myDataList") public String myDataList(Model model, HttpSession session) { //判断是否登陆 if (session.getAttribute("loginUserinfo") == null) { model.addAttribute("errorMsg", "登陆以后才可以操作"); return "/"; } Student student = (Student) session.getAttribute("loginUserinfo"); if (ObjectUtils.isNotEmpty(student.getDormitoryId())) { LambdaQueryWrapper<Student> studentLambdaQueryWrapper = new LambdaQueryWrapper<>(); studentLambdaQueryWrapper.eq(Student::getDormitoryId, student.getDormitoryId()); List<Student> studentList = studentService.list(studentLambdaQueryWrapper); Dormitory dormitory = dormitoryService.getById(student.getDormitoryId()); List<String> stringList = studentList.stream().map(Student::getName).collect(Collectors.toList()); String[] ans2 = stringList.toArray(new String[stringList.size()]); dormitory.setDormUser(String.join(",",ans2)); session.setAttribute("dormUserinfoList", studentList); model.addAttribute("dorminfo", dormitory); } return "myDataList"; }请详细解释每一行代码

好的，我来一行一行地解释这段代码的含义：

@RequestMapping("/myDataList")
public String myDataList(Model model, HttpSession session) {

这里定义了一个请求处理的方法，请求路径为"/myDataList"，方法名为"myDataList"，接受两个参数：Model和HttpSession。

if (session.getAttribute("loginUserinfo") == null) {
    model.addAttribute("errorMsg", "登陆以后才可以操作");
    return "/";
}

这里判断用户是否登录，如果没有登录则将错误信息放入Model中并返回首页"/"。

Student student = (Student) session.getAttribute("loginUserinfo");

从Session中获取已登录的学生信息。

if (ObjectUtils.isNotEmpty(student.getDormitoryId())) {
    LambdaQueryWrapper<Student> studentLambdaQueryWrapper = new LambdaQueryWrapper<>();
    studentLambdaQueryWrapper.eq(Student::getDormitoryId, student.getDormitoryId());
    List<Student> studentList = studentService.list(studentLambdaQueryWrapper);

如果学生信息中宿舍ID不为空，则根据宿舍ID查询所有同宿舍的学生信息。

Dormitory dormitory = dormitoryService.getById(student.getDormitoryId());
List<String> stringList = studentList.stream().map(Student::getName).collect(Collectors.toList());
String[] ans2 = stringList.toArray(new String[stringList.size()]);
dormitory.setDormUser(String.join(",",ans2));

通过宿舍ID获取宿舍信息，将同宿舍的学生姓名放入数组中，并将数组转换成字符串，最后将字符串设置为宿舍信息中的"dormUser"属性。

session.setAttribute("dormUserinfoList", studentList);
model.addAttribute("dorminfo", dormitory);

将同宿舍的学生信息列表放入Session中，并将宿舍信息放入Model中。

return "myDataList";

返回"myDataList"页面。