hibernate中List一对多照射关系详解

2012-07-22

hibernate中List一对多映射关系详解场景：一个Team对一个多个Student，其中Team中的studes属性为List类型直

hibernate中List一对多映射关系详解

场景：一个Team对一个多个Student，其中Team中的studes属性为List类型

直接上代码，测试通过的：

Team.java

package com.fgh.hibernate;import java.util.ArrayList;import java.util.List;/** * 一的一方 * @author fgh * */@SuppressWarnings("unchecked")public class Team {private String id;private String name;private List students = new ArrayList();public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public List getStudents() {return students;}public void setStudents(List students) {this.students = students;}}

Studeng.java

package com.fgh.hibernate;/** * 多的一方 * @author fgh * */public class Student {private String id;private String cardId;private String name;private int age;private Team team;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getCardId() {return cardId;}public void setCardId(String cardId) {this.cardId = cardId;}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 Team getTeam() {return team;}public void setTeam(Team team) {this.team = team;}}

以下三个配置文件均放在src根目录下：

hibernate主配置文件：

hibernate.cfg.xml

<?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.url">jdbc:mysql://localhost:3306/hibernate</property><property name="connection.username">root</property><property name="connection.password">root</property><property name="connection.driver_class">com.mysql.jdbc.Driver</property><property name="dialect">org.hibernate.dialect.MySQLDialect</property><property name="show_sql">true</property><mapping resource="Team.hbm.xml" /><mapping resource="Student.hbm.xml" /></session-factory></hibernate-configuration>
一方配置文件： Team.hbm.xml

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping><class name="com.fgh.hibernate.Team" table="team_list"><id name="id" column="id" type="string"><generator column="name" type="string"></property><list name="students" table="student_list" cascade="all"><key column="team_id"></key><index column="[index]" type="string"></index><one-to-many /></list></class></hibernate-mapping>
多方配置文件： Studeng.hbm.xml

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping><class name="com.fgh.hibernate.Student" table="student_list"><id name="id" column="id" type="string"><generator column="card_id" type="string"></property><property name="name" column="name" type="string"></property><property name="age" column="age" type="int"></property><many-to-one name="team" column="team_id"name="code">package com.fgh.hibernate;import org.hibernate.cfg.Configuration;import org.hibernate.tool.hbm2ddl.SchemaExport;/** * 根据.hbm.xml配置文件创建相应的数据库表 * @author fgh * */public class CreateTable {public static void main(String[] args) {SchemaExport export = new SchemaExport(new Configuration().configure());// 第一个参数表示是否在控制台打印出DDL语句(print the DDL to the console)// 第二个参数表示是否将脚本输出到数据库(export the script to the database)export.create(true, true);}}

运行CreateTable.java 生成对应表，后台打印sql如下：

alter table student_list drop foreign key FKFEDE142211CB0B6Adrop table if exists student_listdrop table if exists team_listcreate table student_list (id varchar(255) not null, card_id varchar(255), name varchar(255), age integer, team_id varchar(255), `index` integer, primary key (id))create table team_list (id varchar(255) not null, name varchar(255), primary key (id))alter table student_list add index FKFEDE142211CB0B6A (team_id), add constraint FKFEDE142211CB0B6A foreign key (team_id) references team_list (id)

ok，表已经创建成功，下面测试保存操作：

InsertTest.java

package com.fgh.hibernate;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.cfg.Configuration;/** * 保存操作测试类 * @author fgh * */public class InsertTest {private static SessionFactory sessionFactory;//创建工厂实例static {try {sessionFactory = new Configuration().configure().buildSessionFactory();} catch (Exception e) {e.printStackTrace();}}@SuppressWarnings("unchecked")public static void main(String[] args) {Session session = sessionFactory.openSession();Transaction tx = null;try {//创建两个teamTeam team = new Team();team.setName("team1");Team team2 = new Team();team2.setName("team2");//创建6个student对象Student student = new Student();student.setAge(20);student.setName("zhangsan");student.setTeam(team);Student student2 = new Student();student2.setAge(24);student2.setName("lisi");student2.setTeam(team);Student student3 = new Student();student3.setAge(24);student3.setName("student3");student3.setTeam(team2);Student student4 = new Student();student4.setAge(24);student4.setName("student4");student4.setTeam(team2);Student student5 = new Student();student5.setAge(24);student5.setName("student5");student5.setTeam(team2);//前两个student属于teamteam.getStudents().add(student);team.getStudents().add(student2);//后三个student属于team2team2.getStudents().add(student3);team2.getStudents().add(student4);team2.getStudents().add(student5);//开启事务tx = session.beginTransaction();//保存team和team2session.save(team);session.save(team2);System.out.println("save success!");//提交事务tx.commit();} catch (Exception e) {e.printStackTrace();if (null != tx) {tx.rollback();}} finally {session.close();}}}

控制打印sql如下：

save success!Hibernate: insert into team_list (name, id) values (?, ?)Hibernate: insert into student_list (card_id, name, age, team_id, id) values (?, ?, ?, ?, ?)Hibernate: insert into student_list (card_id, name, age, team_id, id) values (?, ?, ?, ?, ?)Hibernate: insert into team_list (name, id) values (?, ?)Hibernate: insert into student_list (card_id, name, age, team_id, id) values (?, ?, ?, ?, ?)Hibernate: insert into student_list (card_id, name, age, team_id, id) values (?, ?, ?, ?, ?)Hibernate: insert into student_list (card_id, name, age, team_id, id) values (?, ?, ?, ?, ?)Hibernate: update student_list set team_id=?, `index`=? where id=?Hibernate: update student_list set team_id=?, `index`=? where id=?Hibernate: update student_list set team_id=?, `index`=? where id=?Hibernate: update student_list set team_id=?, `index`=? where id=?Hibernate: update student_list set team_id=?, `index`=? where id=?
02-04插入的是team
05-08插入的是team2

09-13是对student_list表中外键team_id,和排序字段index的维护

student_list表中记录如下：

id name age team_id8a8adb7b34a45b700134a45b72130002 zhangsan 20 8a8adb7b34a45b700134a45b71fc000108a8adb7b34a45b700134a45b72130003 lisi 24 8a8adb7b34a45b700134a45b71fc000118a8adb7b34a45b700134a45b72130005 student3 24 8a8adb7b34a45b700134a45b7213000408a8adb7b34a45b700134a45b72130006 student4 24 8a8adb7b34a45b700134a45b7213000418a8adb7b34a45b700134a45b72140007 student5 24 8a8adb7b34a45b700134a45b721300042

team_list表中记录：

8a8adb7b34a467320134a46733cc0001team18a8adb7b34a467320134a46733e40004team2

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hibernate中List一对多照射关系详解