1、Annotation 注解版
1.1、应用场景（Student-Teacher）：当学生知道有哪些老师教，但是老师不知道自己教哪些学生时，可用单向关联
1.2、创建Teacher类和Student类
package com.shore.model; import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table; /**
* @author DSHORE/2019-9-22
* 多对多，单向关联（注解版）
*/
@Entity
@Table(name="anno_teacher")
public class Teacher {
private Integer id;
private String name;
private Integer age; @Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
Student类
package com.shore.model; import java.util.HashSet;
import java.util.Set; import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table; /**
* @author DSHORE/2019-9-22
* 多对多，单向关联（注解版）
*/
@Entity
@Table(name="anno_student")
public class Student {
private Integer id;
private String number;
private Float sum;
private Set<Teacher> teachers = new HashSet<Teacher>(); @Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public Float getSum() {
return sum;
}
public void setSum(Float sum) {
this.sum = sum;
} /**
* name：中间表的表名
* joinColumns：当前对象所对应的id
* inverseJoinColumns：对方对象所对应的id
*/
@ManyToMany
@JoinTable(name="anno_student_teacher",
joinColumns=@JoinColumn(name="student_id"),
inverseJoinColumns=@JoinColumn(name="teacher_id"))
public Set<Teacher> getTeachers() {
return teachers;
}
public void setTeachers(Set<Teacher> teachers) {
this.teachers = teachers;
}
}
1.3、创建hibernate.cfg.xml核心配置文件
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">123456</property> <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">create</property> <mapping class="com.shore.model.Teacher" />
<mapping class="com.shore.model.Student" />
</session-factory>
</hibernate-configuration>
1.4、开始测试
package com.shore.test; import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.Test; /**
* @author DSHORE/2019-9-22
*
*/
public class AnnotationTest {
@Test
public void test() {//简单测试，只创建表，不插入数据
new SchemaExport(new AnnotationConfiguration().configure()).create(
false, true);
}
}
测试结果图：
2、XML版 的实现
2.1、创建Teacher类和Student类
package com.shore.model; /**
* @author DSHORE/2019-9-22
* 多对多，单向关联（xml版）
*/
public class Teacher {
private Integer id;
private String name;
private Integer age; public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
Student类
package com.shore.model; import java.util.HashSet;
import java.util.Set; /**
* @author DSHORE/2019-9-22
* 多对一，单向关联（xml版）
*/
public class Student {
private Integer id;
private String number;
private Float sum;
private Set<Teacher> teachers = new HashSet<Teacher>(); public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public Float getSum() {
return sum;
}
public void setSum(Float sum) {
this.sum = sum;
}
public Set<Teacher> getTeachers() {
return teachers;
}
public void setTeachers(Set<Teacher> teachers) {
this.teachers = teachers;
}
}
2.2、创建 Teacher.hbm.xml 配置文件和 Student.hbm.xml 配置文件
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.shore.model">
<class name="Teacher" table="xml_teacher">
<id name="id">
<generator class="native"/>
</id>
<property name="name" type="java.lang.String"/>
<property name="age" type="java.lang.Integer"/>
</class>
</hibernate-mapping>
Student.hbm.xml 配置文件
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.shore.model">
<class name="Student" table="xml_student">
<id name="id">
<generator class="native"/>
</id>
<property name="number" type="java.lang.String"/>
<property name="sum" type="java.lang.Float"/> <set name="teachers" table="xml_student_teacher">
<key column="student_id"/> <!-- 当前对象所对应的id -->
<many-to-many class="com.shore.model.Teacher" column="teacher_id"/> <!-- 对方对象所对应的id -->
</set>
</class>
</hibernate-mapping>
2.3、创建hibernate.cfg.xml 核心配置文件
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">123456</property> <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">create</property> <!-- <mapping class="com.shore.model.Teacher" />
<mapping class="com.shore.model.Student" /> -->
<mapping resource="com/shore/model/Teacher.hbm.xml" />
<mapping resource="com/shore/model/Student.hbm.xml" />
</session-factory>
</hibernate-configuration>
2.4、开始测试
package com.shore.test; import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.Test; /**
* @author DSHORE/2019-9-22
*
*/
public class XMLTest {
@Test
public void test() {//简单测试，只创建表，不插入数据
//xml版，这里用的是Configuration()方法。
new SchemaExport(new Configuration().configure()).create(
false, true);
}
}
测试结果图：
Hibernate一对一单向关联映射（Annotation+XML实现）：https://www.cnblogs.com/dshore123/p/11545058.html
Hibernate一对一双向关联映射（Annotation+XML实现）：https://www.cnblogs.com/dshore123/p/11545077.html
Hibernate多对一单向关联映射（Annotation+XML实现）：https://www.cnblogs.com/dshore123/p/11553213.html
Hibernate一对多单向关联映射（Annotation+XML实现）：https://www.cnblogs.com/dshore123/p/11553215.html
Hibernate一对多和多对一双向关联映射（Annotation+XML实现）：https://www.cnblogs.com/dshore123/p/11560433.html
Hibernate多对多单向关联映射（Annotation+XML实现）：https://www.cnblogs.com/dshore123/p/11568536.html
Hibernate多对多双向关联映射（Annotation+XML实现）：https://www.cnblogs.com/dshore123/p/11568963.html
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原创作者：DSHORE 作者主页：http://www.cnblogs.com/dshore123/ 原文出自：https://www.cnblogs.com/dshore123/p/11568536.html 版权声明：欢迎转载，转载务必说明出处。（如果本文对您有帮助，可以点击一下右下角的 推荐，或评论，谢谢！） |