hibernate 多对多注解配置
1、在公司一个员工对应多个部门，一个部门对应多个员工，因此部门与员工之间就是多对多的关系。
Person类的代码如下：
package com.mr.cheng.bean;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.ManyToOne;
import org.hibernate.annotations.Cascade;
@Entity
public class Person {
private Integer id;
private String name;
private int age;
private double price;
private Set<Dept> depts;
/**
* 多对多由一方来完成，
*/
@ManyToMany(cascade=CascadeType.ALL)
@JoinTable(name="personDeptTable",
/**
* 这一方的Id
*/
joinColumns={@JoinColumn(name="personId")},
/**
* 反转的另外一段的列名,既对方一张表的Id
* @return
*/
inverseJoinColumns={@JoinColumn(name="deptId")}
)
public Set<Dept> getDepts() {
return depts;
}
@Override
public String toString() {
return "Person [id=" + id + ", name=" + name + ", age=" + age
+ ", price=" + price + ", depts=" + depts + "]";
}
public void setDepts(Set<Dept> depts) {
this.depts = depts;
}
@Id
@GeneratedValue
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 int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
}
Dept类的代码如下：
package com.mr.cheng.bean;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;
@Entity
@Table(name="deptTable")
public class Dept {
private int id;
private String name;
private Set<Person>persons;
@Id@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@ManyToMany
(mappedBy="depts")
public Set<Person> getPersons() {
return persons;
}
public void setPersons(Set<Person> persons) {
this.persons = persons;
}
}
2、hibernate.hbm.xml配置如下：
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="connection.driver_class">
com.mysql.jdbc.Driver
</property>
<property name="connection.url">
jdbc:mysql://localhost/test
</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<property name="dialect">
org.hibernate.dialect.MySQLDialect
</property>
<!--
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:SXT</property>
<property name="connection.username">scott</property>
<property name="connection.password">tiger</property>
<property name="dialect">org.hibernate.dialect.OracleDialect</property>
-->
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">
org.hibernate.cache.NoCacheProvider
</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<property name="format_sql">true</property>
<mapping class="com.mr.cheng.bean.Dept" />
<mapping class="com.mr.cheng.bean.Person" />
</session-factory>
</hibernate-configuration>
3、测试代码如下：
package com.mr.cheng.test;
import java.util.Date;
import java.util.HashSet;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import com.mr.cheng.bean.Dept;
import com.mr.cheng.bean.Person;
public class HibernateTest {
private static SessionFactory sessionFactory;
//@BeforeClass
public static void beforeClass() {
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
}
//@AfterClass
public static void afterClass() {
sessionFactory.close();
}
@Test
public void testSchemaExport() {
new SchemaExport(new AnnotationConfiguration().configure()).create(true, true);
}
public static void main(String[] args) {
beforeClass();
}
/**
* 多对多单向
*/
@Test
public void testManyToManyAddPersonAndDept(){
new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
Dept dept = new Dept();
dept.setName("财务部");
Dept dept1 = new Dept();
dept1.setName("财务部");
Person person = new Person();
person.setName("A111");
person.setAge(33);
person.setPrice(33);
Person person1 = new Person();
person1.setName("A111");
person1.setAge(33);
person1.setPrice(33);
person.setDepts(new HashSet<Dept>());
person1.setDepts(new HashSet<Dept>());
person.getDepts().add(dept);
person.getDepts().add(dept1);
person1.getDepts().add(dept);
person1.getDepts().add(dept1);
session.save(person1);
session.save(person);
/*session.save(dept1);
session.save(dept);*/
session.getTransaction().commit();
}
/**
* 多对多单向查询 Person 一方
*/
@Test
public void testManyToManyQueryPerson(){
new SchemaExport(new AnnotationConfiguration().configure()).create(false, false);
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
Person p = (Person) session.load(Person.class, 1);
System.out.println(p.getDepts());
session.getTransaction().commit();
}
/**
* 多对多单向查询 Dept 一方
*/
@Test
public void testManyToManyQueryDept(){
new SchemaExport(new AnnotationConfiguration().configure()).create(false, false);
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
Dept dept = (Dept) session.load(Dept.class, 1);
System.out.println(dept.getPersons());
session.getTransaction().commit();
}
@Test
public void testManyToManyAddPersonAndDept1(){
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
Dept dept = new Dept();
dept.setName("财务部");
Dept dept1 = new Dept();
dept1.setName("财务部");
Person person = new Person();
person.setName("A111");
person.setAge(33);
person.setPrice(33);
Person person1 = new Person();
person1.setName("A111");
person1.setAge(33);
person1.setPrice(33);
dept1.setPersons(new HashSet());
dept.setPersons(new HashSet());
dept1.getPersons().add(person1);
dept1.getPersons().add(person);
/* session.save(person1);
session.save(person);*/
session.save(dept1);
session.save(dept);
session.getTransaction().commit();
}
}
