休眠连接两个表

Question

我正在尝试学习 Spring 和 Hibernate 。我有以下表格

在我的数据库表中插入表单值后，我希望它们如下所示：

表名：学生

student_id    studentName
  1.           Jason Stathum

表格名称：studentdetails

studentDetailsid   FatherName   MotherName    student_id
   1                 Mr.X          Mrs. Y        1

但是当我实际在我的数据库中插入值时，studentdetails 表如下所示

表格名称：studentdetails

studentDetailsid   FatherName   MotherName    student_id
   1                 Mr.X          Mrs. Y        NULL

如您所见，一切正常，但只有 student_id 列没有被填满。你能告诉我我做错了什么吗？

这是我的代码：

模型类：学生

package com.spring.org.model

@Entity
@Table(name = "student")
public class Student {

@Id 
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name="student_id", nullable= false)
private Integer studentId;
private String studentName;

@OneToMany(cascade = CascadeType.ALL, mappedBy = "student")
private List<StudentDetails> studentDetails = new ArrayList<StudentDetails>();

// Getters and Setters

模型类：StudentDetails

@Entity
@Table(name = "studentDetails")
public class StudentDetails {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer studentDetailsId;
private String FatherName;
private String MotherName;

@ManyToOne
@JoinColumn(name="student_id")
private Student student;

// Getters and Setters

控制器

 @RequestMapping(value="addstudent", method = RequestMethod.GET)
public String addStudent(@ModelAttribute("secret") Student student, BindingResult result, Model map)
{
    map.addAttribute("student", new Student());     
    return "addStudent";
}

@RequestMapping(value="addstudent", method = RequestMethod.POST)
public String saveStudent(@ModelAttribute("secret") Student student, BindingResult result, Model map)
{
    studentService.addStudent(student);
    map.addAttribute("success", "Submitted");
    return "msg";

}

JSP 页面：表单

<c:url var="saveUrl" value="/addstudent" />
 <form:form modelAttribute="secret" method="POST" action="${saveUrl}">
  <table>
  <tr>
     <td><form:label path="studentName">Student Name:</form:label></td>
     <td><form:input path="studentName"/></td>
 </tr> 

 <tr>
    <td><form:label path="studentDetails[0].FatherName">Father Name:</form:label></td>
    <td><form:input path="studentDetails[0].FatherName"/></td>
 </tr>

 <tr>
   <td><form:label path="studentDetails[0].MotherName">Mother Name:</form:label></td>
   <td><form:input path="studentDetails[0].MotherName"/></td>
 </tr>
</table>

 <input type="submit" value="Save" />
</form:form>

StudentDaoImpl

@Override
public void addStudent(Student student) {

    Session session = getSessionFactory().openSession();
    Transaction tx;
    tx = session.beginTransaction();
    session.save(student);  

    tx.commit();
}

Answer 1

从StudentDetails 中的student 属性中删除@JoinColumn 注释应该可以解决问题：

@ManyToOne
//@JoinColumn(name="student_id")
private Student student;

Answer 2

更改此片段：

@ManyToOne
@JoinColumn(name="student_id")
private Student student;

到：

@ManyToOne
private Student student;

这应该有效。

Answer 3

我已经设法解决了这个问题，我希望有一天这会对其他人有所帮助。 我对我的

进行了一些更改

模型类：学生

@Entity
@Table(name = "student")
public class Student {

@Id 
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name="student_id", nullable= false)
private Integer studentId;
private String studentName;

@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name="student_id", referencedColumnName="student_id")
private List<StudentDetails> studentDetails = new ArrayList<StudentDetails>();

// Getters and Setters

然后从模型类中删除private Student student; 属性：StudentDetails。所以现在看起来像这样：

模型类：StudentDetails

@Entity
@Table(name = "studentDetails")
public class StudentDetails {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer studentDetailsId;
private String FatherName;
private String MotherName;

// Getters and Setters