【发布时间】：2018-06-09 14:46:36
【问题描述】：
已编辑
（与How to use @Id with String Type in JPA / Hibernate? 不完全相同）
原因：
-
当时，我遇到的错误是这样的：
org.hibernate.id.IdentifierGenerationException: Unknown integral data type for ids : java.lang.String ---- many lines below at ajfmo.studycontrol.DAO.StudentDAO.createStudent(StudentDAO.java:49)但这不是我遇到的唯一错误，我在 cmets 中提到我在执行此操作时遇到了困难，因为我无法使其工作（初学者）。
即使我目前遇到的错误是由 @GeneratedValue 注释引起的，但该注释不是必需的，因此我可以摆脱它和许多其他注释。
-
最重要的是，异常不一样
org.hibernate.TypeMismatchException: Provided id of the wrong type. Expected: class java.lang.String got class java.lang.Long 我仍然看不到“重复帖子”之间的关系。
您好，感谢您抽出宝贵时间。
正如标题所说，我需要将数据保存到一个名为“学生”的表中，其中学生有一个职业和一个部门，但职业和部门有很多学生。
这是我的数据库图：
我将发布几乎所有代码，以确保您了解我在做什么。 我正在自学 Hibernate 并将其作为一种练习，以更好地理解这个工具并提高我的技能和知识。我不明白我在做什么，但我认为我会走上好的道路。
这是我的项目结构：
这是我需要完成工作的窗口...
我从 ComboBoxes 中选择一个选项，并填写所需的信息，例如 ID 和 Name，然后单击 Guardar，或以英文保存。
在这一刻，这是我得到的例外：
org.hibernate.id.IdentifierGenerationException: Unknown integral data type for ids : java.lang.String
---- many lines below
at ajfmo.studycontrol.DAO.StudentDAO.createStudent(StudentDAO.java:49)
经过多次尝试并遵循大量“教程”、视频和指南后，我仍然无法使其正常工作...
如果你有一个类似案例的例子，如果你给我看，我会非常感激的
这些是我的 POJO/BEAN 类。
学生.java
// imports
@Entity
@Table(name = "student", catalog = "students")
public class Student implements java.io.Serializable {
private static final long serialVersionUID = -5712510402302219163L;
private String studentId;
private Career career;
private Section section;
private String studentName;
public Student() {
}
public Student(String studentId, String studentName, Career career, Section section) {
this.studentId = studentId;
this.studentName = studentName;
this.career = career;
this.section = section;
}
@Id
@GeneratedValue
@Column(name = "student_id", unique = true, nullable = false)
public String getStudentId() {
return this.studentId;
}
public void setStudentId(String studentId) {
this.studentId = studentId;
}
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "student_career", nullable = false, foreignKey = @ForeignKey(name = "fk_student_career"))
public Career getCareer() {
return this.career;
}
public void setCareer(Career career) {
this.career = career;
}
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "student_section", nullable = false, foreignKey = @ForeignKey(name = "fk_student_section"))
public Section getSection() {
return this.section;
}
public void setSection(Section section) {
this.section = section;
}
@Column(name = "student_name", nullable = false, length = 100)
public String getStudentName() {
return this.studentName;
}
public void setStudentName(String studentName) {
this.studentName = studentName;
}
/*
* (non-Javadoc)
*
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return "Student [studentId=" + studentId + ", career=" + career + ", section=" + section + ", studentName="
+ studentName + "]";
}
}
Career.java
// Imports
/**
* Career generated by hbm2java
*/
@Entity
@Table(name = "career", catalog = "students", uniqueConstraints = @UniqueConstraint(columnNames = "career_name"))
public class Career implements java.io.Serializable {
private static final long serialVersionUID = 4710263584653513266L;
private String careerId;
private String careerName;
private Set<Student> students = new HashSet<Student>(0);
public Career() {
}
public Career(String careerId, String careerName) {
this.careerId = careerId;
this.careerName = careerName;
}
public Career(String careerId, String careerName, Set<Student> students) {
this.careerId = careerId;
this.careerName = careerName;
this.students = students;
}
public Career(Career studentCareer) {
this.careerId = studentCareer.careerId;
}
@Id
@GeneratedValue
@Column(name = "career_id", unique = true, length = 25)
public String getCareerId() {
return this.careerId;
}
public void setCareerId(String careerId) {
this.careerId = careerId;
}
@Column(name = "career_name", unique = true, length = 100)
public String getCareerName() {
return this.careerName;
}
public void setCareerName(String careerName) {
this.careerName = careerName;
}
@OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinColumn(name = "career_id")
public Set<Student> getStudents() {
return this.students;
}
public void setStudents(Set<Student> students) {
this.students = students;
}
/*
* (non-Javadoc)
*
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return careerName;
}
}
Section.java
// Imports
/**
* Section generated by hbm2java
*/
@Entity
@Table(name = "section", catalog = "students", uniqueConstraints = @UniqueConstraint(columnNames = "section_name"))
public class Section implements java.io.Serializable {
private static final long serialVersionUID = 6380772442291491780L;
private String sectionId;
private String sectionName;
private Set<Student> students = new HashSet<Student>(0);
public Section() {
}
public Section(String sectionId, String sectionName) {
this.sectionId = sectionId;
this.sectionName = sectionName;
}
public Section(String sectionId, String sectionName, Set<Student> students) {
this.sectionId = sectionId;
this.sectionName = sectionName;
this.students = students;
}
public Section(Section studentSection) {
this.sectionId = studentSection.sectionId;
}
@Id
@GeneratedValue
@Column(name = "section_id", unique = true, length = 25)
public String getSectionId() {
return this.sectionId;
}
public void setSectionId(String sectionId) {
this.sectionId = sectionId;
}
@Column(name = "section_name", unique = true, length = 200)
public String getSectionName() {
return this.sectionName;
}
public void setSectionName(String sectionName) {
this.sectionName = sectionName;
}
@OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinColumn(name = "section_id")
public Set<Student> getStudents() {
return this.students;
}
public void setStudents(Set<Student> students) {
this.students = students;
}
/*
* (non-Javadoc)
*
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return sectionId;
}
}
这些是我的 DAO 类：
StudentDAO.java
// Imports
public class StudentDAO {
// Objects
private final Session session = HibernateUtil.getSessionFactory();
private Transaction transaction = null;
private Set<Student> students = new HashSet<Student>();
private Career career;
private Section section;
private Student student;
/**
* Create student in database
*/
public void createStudent(String studentId, String studentName, Career studentCareer, Section studentSection) {
career = new Career(studentCareer);
section = new Section(studentSection);
student = new Student(studentId, studentName, studentCareer, studentSection);
students.add(student);
career.setStudents(students);
section.setStudents(students);
try {
transaction = session.beginTransaction();
session.save(career);
session.save(section);
session.save(student);
transaction.commit();
} catch (HibernateException e) {
e.printStackTrace();
}
HibernateUtil.shutdown();
}
public List<Career> careerCriteria() {
CriteriaBuilder builder = session.getCriteriaBuilder();
CriteriaQuery<Career> criteria = builder.createQuery(Career.class);
Root<Career> root = criteria.from(Career.class);
criteria.select(root);
List<Career> resultset = session.createQuery(criteria).getResultList();
return resultset;
}
public List<Section> sectionCriteria() {
CriteriaBuilder builder = session.getCriteriaBuilder();
CriteriaQuery<Section> criteria = builder.createQuery(Section.class);
Root<Section> root = criteria.from(Section.class);
criteria.select(root);
List<Section> resultset = session.createQuery(criteria).getResultList();
return resultset;
}
}
CareerDAO.java
public class CareerDAO {
// Objects
private Career career;
// Hibernate Utils
private Session session = HibernateUtil.getSessionFactory();
private Transaction transaction = null;
/***************/
/*** ***/
/*** Methods ***/
/*** ***/
/***************/
public void createCareer(String careerID, String careerName) {
career = new Career(careerID, careerName);
try {
transaction = session.beginTransaction();
session.save(career);
transaction.commit();
} catch (HibernateException e) {
e.printStackTrace();
}
}
}
SectionDAO.java
public class SectionDAO {
// Objects
private Section section;
// Hibernate
private Session session = HibernateUtil.getSessionFactory();
private Transaction transaction = null;
/***************/
/*** ***/
/*** Methods ***/
/*** ***/
/***************/
public void createSection(String sectionID, String sectionD) {
section = new Section(sectionID, sectionD);
try {
transaction = session.beginTransaction();
session.save(section);
transaction.commit();
} catch (HibernateException e) {
e.printStackTrace();
}
}
}
这是我的学生视图控制器。
package ajfmo.studycontrol.view;
//Imports
public class StudentView implements Initializable {
// Objetos
// Colections
// FXML objects
/***************/
/*** ***/
/*** Methods ***/
/*** ***/
/***************/
/**
* Fill Carrer's ComboBox
*
* @param careersList
*/
private void fillCareersCbo(ObservableList<Career> careersList) {
for (Career careers : student.careerCriteria()) {
careersList.add(new Career(careers.getCareerId(), careers.getCareerName()));
}
}
/**
* Fills Section's ComboBox
*/
private void fillSectionsCbo(ObservableList<Section> sectionList) {
for (Section sections : student.sectionCriteria()) {
sectionList.add(new Section(sections.getSectionId(), sections.getSectionName()));
}
}
/**
* Events listeners
*/
/**
* Calls 'createStudent' method from StudentDAO
*/
@FXML
private void create() {
student.createStudent(txtCodigo.getText(), txtNombre.getText(), cboCarrera.getValue(),
cboSeccion.getValue());
}
/**
* Close SessionFactory and current window
*/
@FXML
private void salir() {
HibernateUtil.shutdown();
Stage stage = (Stage) btnSalir.getScene().getWindow();
stage.close();
}
}
非常感谢您阅读本文。
P.S.：非常感谢任何额外的建议。
【问题讨论】：
标签： java mysql hibernate javafx