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

<!DOCTYPE hibernate-configuration PUBLIC
	"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
	"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
	<!-- 把name="foo"属性去掉 -->
	<session-factory>
		<!--这里是Hibernate框架的基本配置：数据库连接，框架参数的配置，映射文件的配置  -->
		<!-- 方言，表示Hibernate框架在与某个数据库进行映射，才能自动生成某个数据库特有的SQL语句 -->
		<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
		<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
		<property name="connection.url">jdbc:mysql://localhost:3306/myschool?characterEncoding=utf-8</property>
		<property name="connection.username">root</property>
		<property name="connection.password">root</property>
		
		<!--Hibernate框架的基本配置  -->
		<!-- 打印sql语句，一般开发时运用 ，跟踪自动生成的Sql语句-->
		<property name="show_sql">true</property>
		<!-- 格式化打印的sql语句，一般开发时运用，便于区分关键字 -->
		<property name="format_sql">true</property>
		<!--此属性表示根据当前线程来操作数据，可以提交或者回滚  -->
		<property name="current_session_context_class">thread</property>
		<!--数据库中的表结构可以随映射文件的配置发生改变 -->
		<!-- <property name="hbm2ddl.auto">create</property> --> 
		<!--映射文件加载  -->
		<mapping resource="com/zhq/entity/Grade.hbm.xml"/>
		<mapping resource="com/zhq/entity/Subject.hbm.xml"/>
		<mapping resource="com/zhq/entity/Students.hbm.xml"/>
		<mapping resource="com/zhq/entity/Teachers.hbm.xml"/>
		<mapping resource="com/zhq/entity/StudentsInfo.hbm.xml"/>
	</session-factory>
</hibernate-configuration>

3. 多对一相关的举例配置文件Subject.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!--映射文件的根节点，package:表示实体对象的包名  -->
<hibernate-mapping package="com.zhq.entity">
  <!--class:表示实体类，name:类名 table:表示数据库中的表名  -->
  <class name="Subject" table="subject">
  	<!--表示主键  -->
  	<id name="subjectNo" column="subjectNo" type="int">
  	<!--主键的生成策略，native:表示交由数据库按自身特定的自动增长策略来自动生成增长值  。-->
  		<generator class="native"/>
  	</id>
  	<!--表示主键和外键之外的普通列name:表示实体对象的属性名，column:数据库表的列名，如果属性名和列名一致可以省略column。  -->
  	<property name="subjectName"/>
  	<property name="classHour"/>
  	<!--多对一的关系映射 name:是外键对象属性名  class:实体类型  -->
  	<many-to-one name="grade" class="Grade">
  		<!--name:表示外键列 查询数据时，根据外键列的值取得实体对象，封装在外键对象属性中  -->
  		<column name="gradeId"/>
  	</many-to-one>
  </class>
  <!-- 可以在一个文件中配置多个实体映射对象，但通常情况下不会这样子做。
  	<class name="XXX" table="XXX">
  	</class>
   -->
</hibernate-mapping>

4. 一对多相关的举例配置文件Grade.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!--映射文件的根节点，package:表示实体对象的包名  -->
<hibernate-mapping package="com.zhq.entity">
  <!--class:表示实体类，name:类名 table:表示数据库中的表名  -->
  <class name="Grade" table="grade">
  	<!--表示主键  -->
  	<id name="gradeId" column="gradeId" type="int">
  	<!--主键的生成策略，native:表示交由数据库按自身特定的自动增长策略来自动生成增长值  。-->
  		<generator class="native"/>
  	</id>
  	<!--表示主键和外键之外的普通列name:表示实体对象的属性名，column:数据库表的列名，如果属性名和列名一致可以省略column。  -->
  	<property name="gradeName" column="gradeName" type="string" length="20"></property>
  	<!--一对多的映射 Set List Map  -->
  	<!--name:封装外键对象的属性  -->
  	<set name="subjects">
  		<!--年级表的主键  -->
  		<key column="gradeId"/>
  		<!-- 外键对象 -->
  		<one-to-many class="Subject"/>
  	</set>
  </class>
  <!-- 可以在一个文件中配置多个实体映射对象，但通常情况下不会这样子做。
  	<class name="XXX" table="XXX">
  	</class>
   -->
</hibernate-mapping>

5. 多对多相关的举例配置文件Students.hbm.xml和Teachers.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!--映射文件的根节点，package:表示实体对象的包名  -->
<hibernate-mapping package="com.zhq.entity">
  <!--class:表示实体类，name:类名 table:表示数据库中的表名  -->
  <class name="Students" table="students">
  	<!--表示主键  -->
  	<id name="studentId" column="studentId" type="int">
  	<!--主键的生成策略，native:表示交由数据库按自身特定的自动增长策略来自动生成增长值  。-->
  		<generator class="native"/>
  	</id>
  	<!--表示主键和外键之外的普通列name:表示实体对象的属性名，column:数据库表的列名，如果属性名和列名一致可以省略column。  -->
  	<property name="studentName"/>
  	<!--一对一 ，主表，one-to-many property-ref="student"是子表中关联的外键对象名称 -->
  	<one-to-one name="studentInfo" class="StudentsInfo" property-ref="student"/>
  	<!-- 多对多的处理 -->
  	<!--根据学员编号获取老师的编号，再根据老师的编号编号获取老师的信息封装在teachers属性中  -->
  	<set name="teachers" table="s_t">
  		<key column="studentId"/>
  		<many-to-many class="Teachers" column="teacherId"/>
  	</set>
  </class>
  <!-- 可以在一个文件中配置多个实体映射对象，但通常情况下不会这样子做。
  	<class name="XXX" table="XXX">
  	</class>
   -->
</hibernate-mapping>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!--映射文件的根节点，package:表示实体对象的包名  -->
<hibernate-mapping package="com.zhq.entity">
  <!--class:表示实体类，name:类名 table:表示数据库中的表名  -->
  <class name="Teachers" table="teachers">
  	<!--表示主键  -->
  	<id name="teacherId" column="teacherId" type="int">
  	<!--主键的生成策略，native:表示交由数据库按自身特定的自动增长策略来自动生成增长值  。-->
  		<generator class="native"/>
  	</id>
  	<!--表示主键和外键之外的普通列name:表示实体对象的属性名，column:数据库表的列名，如果属性名和列名一致可以省略column。  -->
  	<property name="teacherName"/>
  	<!-- 多对多的处理 -->
  	<!--根据老师编号获取学生的编号，再根据学生的编号编号获取学生的信息封装在students属性中  -->
  	<set name="students" table="s_t">
  		<key column="teacherId"/>
  		<many-to-many class="Students" column="studentId"/>
  	</set>
  </class>
  <!-- 可以在一个文件中配置多个实体映射对象，但通常情况下不会这样子做。
  	<class name="XXX" table="XXX">
  	</class>
   -->
</hibernate-mapping>

6. 一对一相关的举例配置文件Students.hbm.xml和StudentsInfo.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!--映射文件的根节点，package:表示实体对象的包名  -->
<hibernate-mapping package="com.zhq.entity">
  <!--class:表示实体类，name:类名 table:表示数据库中的表名  -->
  <class name="Students" table="students">
  	<!--表示主键  -->
  	<id name="studentId" column="studentId" type="int">
  	<!--主键的生成策略，native:表示交由数据库按自身特定的自动增长策略来自动生成增长值  。-->
  		<generator class="native"/>
  	</id>
  	<!--表示主键和外键之外的普通列name:表示实体对象的属性名，column:数据库表的列名，如果属性名和列名一致可以省略column。  -->
  	<property name="studentName"/>
  	<!--一对一 ，主表，one-to-many property-ref="student"是子表中关联的外键对象名称 -->
  	<one-to-one name="studentInfo" class="StudentsInfo" property-ref="student"/>
  	<!-- 多对多的处理 -->
  	<!--根据学员编号获取老师的编号，再根据老师的编号编号获取老师的信息封装在teachers属性中  -->
  	<set name="teachers" table="s_t">
  		<key column="studentId"/>
  		<many-to-many class="Teachers" column="teacherId"/>
  	</set>
  </class>
  <!-- 可以在一个文件中配置多个实体映射对象，但通常情况下不会这样子做。
  	<class name="XXX" table="XXX">
  	</class>
   -->
</hibernate-mapping>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!--映射文件的根节点，package:表示实体对象的包名  -->
<hibernate-mapping package="com.zhq.entity">
  <!--class:表示实体类，name:类名 table:表示数据库中的表名  -->
  <class name="StudentsInfo" table="studentsInfo">
  	<!--表示主键  -->
  	<id name="studentInfoId" column="studentInfoId" type="int">
  	<!--主键的生成策略，native:表示交由数据库按自身特定的自动增长策略来自动生成增长值  。-->
  		<generator class="native"/>
  	</id>
  	<!--表示主键和外键之外的普通列name:表示实体对象的属性名，column:数据库表的列名，如果属性名和列名一致可以省略column。  -->
  	<property name="sex"/>
  	<!--一对一 ，有外键的表，子表，其实是一对多的关系，加 unique="true"唯一约束，而成了一对一-->
    <many-to-one name="student" column="studentId" class="Students" unique="true"/>
  </class>
  <!-- 可以在一个文件中配置多个实体映射对象，但通常情况下不会这样子做。
  	<class name="XXX" table="XXX">
  	</class>
   -->
</hibernate-mapping>

7. 相关实体类Grade.java，Students.java，StudentsInfo.java，Subject.java，Teachers.java

package com.zhq.entity;

import java.util.Set;

public class Grade {
	private int gradeId;
	private String gradeName;
	private Set<Subject> 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<Subject> getSubjects() {
		return subjects;
	}
	public void setSubjects(Set<Subject> 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> 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<Teachers> getTeachers() {
		return teachers;
	}
	public void setTeachers(Set<Teachers> 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> 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<Students> getStudents() {
		return students;
	}
	public void setStudents(Set<Students> students) {
		this.students = students;
	}
	
}

8. 测试功能所用到相关的类GradeController.java，StudentController.java，SubjectController.java，TeacherController.java

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<Grade> 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<Students> 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<Subject> 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<Teachers> 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();
	}

}