java - 使用@Query 注释按名字排序数据库信息不起作用，我该如何解决？

Question

这是我的学生资料库..

  @Query(value = "SELECT * FROM Student order by last_name ASC", nativeQuery = true)
  public List<Student> orderByLastName();

  @Query(value = "SELECT * FROM Student order by first_name ASC", nativeQuery = true)
  public List<Student> orderByFirstName();

这是我的服务和我的 Controller

  public List<Student> showAllStudentsByFirst()
  {
    List<Student> students = new ArrayList<>();
    for (Student student : studentRepository.findAll())
    {
      students.add(student);
    }
    studentRepository.orderByFirstName();
    return students;
  }

  public List<Student> showAllStudentsByLast()
  {
    List<Student> students = new ArrayList<>();
    for (Student student : studentRepository.findAll())
    {
      students.add(student);
    }
    studentRepository.orderByLastName();
    return students;
  }

  @GetMapping("/listByFirst")
  public String listStudentsByFirst(Model model)
  {
    List<Student> students = studentService.showAllStudentsByFirst();
    model.addAttribute("students", students);

    return "list-students";
  }

  @GetMapping("/listByLast")
  public String listStudentsByLast(Model model)
  {
    List<Student> students = studentService.showAllStudentsByLast();
    model.addAttribute("students", students);

    return "list-students";
  }

该 url 有效，而且当我单击按钮 Orderby First 或 order by last 时，这是控制台中显示的消息

: select student0_.student_id as student_1_1_, student0_.email as email2_1_, student0_.first_name as first_na3_1_, student0_.last_name as last_nam4_1_ from user_db.student student0_
2019-04-15 14:11:46.059 DEBUG 10392 --- [nio-8080-exec-1] org.hibernate.SQL                        : SELECT * FROM Student order by first_name ASC

其他一切正常，但名称没有按 first 或 last 返回 acending 表，仅供引用这是我的 jsp 代码

   <input type="button" value="Sort By First Name"
               onclick="window.location.href='listByFirst'; return false;"/>
        <br/>
        <input type="button" value="Sort By Last Name"
               onclick="window.location.href='listByLast'; return false;"/>

只是订购的表没有返回，我该如何解决？谢谢!

Answer 1

两种下单方式你都不要用返回。它们返回一个按照查询中定义的方式排序的新列表。

相反，您执行 findAll 来创建您显示的输出。并且对订单方法的调用简单地衰减为空。

转储服务中两个方法的前四行，并简单地从订单方法返回值:

public List<Student> showAllStudentsByFirst() {
    return studentRepository.orderByFirstName();
}

public List<Student> showAllStudentsByLast() {
    return studentRepository.orderByLastName();
}