hibernate多对一，一对多，多对多，一对一举例案例
1.项目结构
2. 主配置文件 hibernate.cfg.xml
org.hibernate.dialect.MySQLDialect
com.mysql.jdbc.Driver
jdbc:mysql://localhost:3306/myschool?characterEncoding=utf-8
root
root
true
true
thread
3. 多对一相关的举例配置文件Subject.hbm.xml
4. 一对多相关的举例配置文件Grade.hbm.xml
5. 多对多相关的举例配置文件Students.hbm.xml和Teachers.hbm.xml
6. 一对一相关的举例配置文件Students.hbm.xml和StudentsInfo.hbm.xml
package com.zhq.entity;
import java.util.Set;
public class Grade {
private int gradeId;
private String gradeName;
private Set subjects;
public int getGradeId() {
return gradeId;
}
public void setGradeId(int gradeId) {
this.gradeId = gradeId;
}
public String getGradeName() {
return gradeName;
}
public void setGradeName(String gradeName) {
this.gradeName = gradeName;
}
public Set getSubjects() {
return subjects;
}
public void setSubjects(Set subjects) {
this.subjects = subjects;
}
@Override
public String toString() {
return "Grade [gradeId=" + gradeId + ", gradeName=" + gradeName + "]";
}
}
package com.zhq.entity;
import java.util.Set;
public class Students {
private int studentId;
private String studentName;
private StudentsInfo studentInfo;
private Set teachers;
public int getStudentId() {
return studentId;
}
public void setStudentId(int studentId) {
this.studentId = studentId;
}
public String getStudentName() {
return studentName;
}
public void setStudentName(String studentName) {
this.studentName = studentName;
}
public StudentsInfo getStudentInfo() {
return studentInfo;
}
public void setStudentInfo(StudentsInfo studentInfo) {
this.studentInfo = studentInfo;
}
public Set getTeachers() {
return teachers;
}
public void setTeachers(Set teachers) {
this.teachers = teachers;
}
}
package com.zhq.entity;
public class StudentsInfo {
private int studentInfoId;
private String sex;
private Students student;
public int getStudentInfoId() {
return studentInfoId;
}
public void setStudentInfoId(int studentInfoId) {
this.studentInfoId = studentInfoId;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Students getStudent() {
return student;
}
public void setStudent(Students student) {
this.student = student;
}
}
package com.zhq.entity;
public class Subject {
private int subjectNo;
private String subjectName;
private int classHour;
//年级编号外键，实体类采用外键对象来处理 多对一
private Grade grade;
public int getSubjectNo() {
return subjectNo;
}
public void setSubjectNo(int subjectNo) {
this.subjectNo = subjectNo;
}
public String getSubjectName() {
return subjectName;
}
public void setSubjectName(String subjectName) {
this.subjectName = subjectName;
}
public int getClassHour() {
return classHour;
}
public void setClassHour(int classHour) {
this.classHour = classHour;
}
public Grade getGrade() {
return grade;
}
public void setGrade(Grade grade) {
this.grade = grade;
}
@Override
public String toString() {
return "Subject [subjectNo=" + subjectNo + ", subjectName=" + subjectName + ", classHour=" + classHour + ", gradeName=" + grade.getGradeName() + "]";
}
}
package com.zhq.entity;
import java.util.Set;
public class Teachers {
private int teacherId;
private String teacherName;
private Set students;
public int getTeacherId() {
return teacherId;
}
public void setTeacherId(int teacherId) {
this.teacherId = teacherId;
}
public String getTeacherName() {
return teacherName;
}
public void setTeacherName(String teacherName) {
this.teacherName = teacherName;
}
public Set getStudents() {
return students;
}
public void setStudents(Set students) {
this.students = students;
}
}
package com.zhq.controller;
import java.util.List;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.zhq.entity.Grade;
import com.zhq.entity.Subject;
import com.zhq.util.SessionFactoryUtil;
public class GradeController {
public static void main(String[] args) {
/*增
* Grade g=new Grade();
g.setGradeName("大三");
add(g);
*/
read();
/*通过主键查询某个
readOne(1);
*/
/*通过主键删除
delete(29);
*/
/*通过主键修改
* Grade g=new Grade();
g.setGradeId(27);
g.setGradeName("大三");
update(g);
*/
}
//查全部
public static void read() {
//获取连接Session,此对象用于操作数据库对象
Session session=SessionFactoryUtil.getSession();
//开启事务，如果是增删改的操作，必须要提交事务
session.beginTransaction();
//根据Session连接对象操作数据库，"from Grade"是HQL语言，注意：Grade是表示实体对象
Query query=session.createQuery("from Grade");
@SuppressWarnings("unchecked")
List grades=query.list();
for(Grade grade:grades){
System.out.println(grade);
for(Subject subject:grade.getSubjects()) {
System.out.println(subject);
}
}
session.close();
}
//查单个对象
public static void readOne(int gradeId) {
//获取连接Session,此对象用于操作数据库对象
Session session=SessionFactoryUtil.getSession();
//开启事务，如果是增删改的操作，必须要提交事务
session.beginTransaction();
Grade g=(Grade) session.get(Grade.class, gradeId);
if(g!=null) {
System.out.println(g);
}else {
System.out.println("没有找到相关数据");
}
}
//增
public static void add(Grade g) {
Session session=SessionFactoryUtil.getSession();
Transaction tx=null;
try {
tx=session.beginTransaction();
session.save(g);
tx.commit();
} catch (Exception e) {
tx.rollback();
}
}
//删
public static void delete(int gradeId) {
Session session=SessionFactoryUtil.getSession();
Transaction tx=null;
try {
tx=session.beginTransaction();
Grade g=(Grade) session.get(Grade.class, gradeId);
if(g!=null) {
session.delete(g);
}else {
System.out.println("没有找到相关数据");
}
tx.commit();
} catch (Exception e) {
tx.rollback();
}
}
//改
public static void update(Grade g) {
Session session=SessionFactoryUtil.getSession();
Transaction tx=null;
try {
tx=session.beginTransaction();
session.update(g);
tx.commit();
} catch (Exception e) {
tx.rollback();
}
}
}
package com.zhq.controller;
import java.util.List;
import org.hibernate.Session;
import com.zhq.entity.Students;
import com.zhq.entity.StudentsInfo;
import com.zhq.entity.Teachers;
import com.zhq.util.SessionFactoryUtil;
public class StudentController {
public static void main(String[] args) {
add();
read();
}
private static void add() {
Session session=SessionFactoryUtil.getSession();
session.beginTransaction();
Students student=new Students();
StudentsInfo studentInfo=new StudentsInfo();
student.setStudentName("大熊");
session.save(student);
studentInfo.setSex("男");
studentInfo.setStudent(student);
session.save(studentInfo);
session.getTransaction().commit();
}
private static void read() {
Session session=SessionFactoryUtil.getSession();
session.beginTransaction();
@SuppressWarnings("unchecked")
List list=session.createQuery("from Students").list();
for(Students student:list) {
System.out.println(student.getStudentName()+"的老师：");
for(Teachers teacher:student.getTeachers()) {
System.out.print(teacher.getTeacherName()+",");
}
System.out.println();
}
session.getTransaction().commit();
}
}
package com.zhq.controller;
import java.util.List;
import org.hibernate.Session;
import com.zhq.entity.Subject;
import com.zhq.util.SessionFactoryUtil;
public class SubjectController {
public static void main(String[] args) {
read();
}
private static void read() {
Session session=SessionFactoryUtil.getSession();
session.beginTransaction();
@SuppressWarnings("unchecked")
List list=session.createQuery("from Subject").list();
for(Subject subject:list) {
System.out.println(subject);
}
session.getTransaction().commit();
}
}
package com.zhq.controller;
import java.util.List;
import org.hibernate.Session;
import com.zhq.entity.Students;
import com.zhq.entity.Teachers;
import com.zhq.util.SessionFactoryUtil;
public class TeacherController {
public static void main(String[] args) {
read();
}
private static void read() {
Session session=SessionFactoryUtil.getSession();
session.beginTransaction();
@SuppressWarnings("unchecked")
List list=session.createQuery("from Teachers").list();
for(Teachers teacher:list) {
System.out.println(teacher.getTeacherName()+"的学生：");
for(Students student:teacher.getStudents()) {
System.out.print(student.getStudentName()+",");
}
System.out.println();
}
session.getTransaction().commit();
}
}