例子下载地址http://putaoputao.qupan.cc/7008003.html
一.存user
1.Group.java
package com.bjsxt.hibernate; import java.util.HashSet; 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.OneToMany; import javax.persistence.Table; @Entity @Table(name="t_group") public class Group { private int id; private String name; private Set<User> users = new HashSet<User>(); @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; } @OneToMany(mappedBy="group", cascade={CascadeType.ALL} ) public Set<User> getUsers() { return users; } public void setUsers(Set<User> users) { this.users = users; } }
2.User.java 注解@ManyToOne(cascade={CascadeType.ALL})中CascadeType.ALL代表对一个对象操作也会影响关联的对象。
CascadeType.ALL和CascadeType.PERSIST和CascadeType.REMOVE最常用。
package com.bjsxt.hibernate; import javax.persistence.CascadeType; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.ManyToOne; import javax.persistence.Table; @Entity @Table(name="t_user") public class User { private int id; private String name; private Group group; @ManyToOne(cascade={CascadeType.ALL}) public Group getGroup() { return group; } public void setGroup(Group group) { this.group = group; } @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; } }
3.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.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost/gjl</property> <property name="connection.username">root</property> <property name="connection.password">wodemima</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> <!-- Drop and re-create the database schema on startup <property name="hbm2ddl.auto">update</property> --> <!-- <mapping resource="com/bjsxt/hibernate/Group.hbm.xml"/> <mapping resource="com/bjsxt/hibernate/User.hbm.xml"/> --> <mapping class="com.bjsxt.hibernate.Group"/> <mapping class="com.bjsxt.hibernate.User"/> </session-factory> </hibernate-configuration>
4.测试程序
HibernateORMappingTest
package test.com.bjsxt.hibernate; 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.bjsxt.hibernate.Group; import com.bjsxt.hibernate.User; public class HibernateORMappingTest { private static SessionFactory sessionFactory; @BeforeClass public static void beforeClass() { new SchemaExport(new AnnotationConfiguration().configure()).create(false, true); sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory(); } @AfterClass public static void afterClass() { sessionFactory.close(); } @Test public void testSaveUser() { User u = new User(); u.setName("u1"); Group g = new Group(); g.setName("g1"); u.setGroup(g); Session s = sessionFactory.getCurrentSession(); s.beginTransaction(); //s.save(g); s.save(u); s.getTransaction().commit(); } @Test public void testSaveGroup() { User u1 = new User(); u1.setName("u1"); User u2 = new User(); u2.setName("u2"); Group g = new Group(); g.setName("g1"); g.getUsers().add(u1); g.getUsers().add(u2); u1.setGroup(g); u2.setGroup(g); Session s = sessionFactory.getCurrentSession(); s.beginTransaction(); //s.save(g); s.save(g); s.getTransaction().commit(); } @Test public void testGetUser() { testSaveGroup(); Session s = sessionFactory.getCurrentSession(); s.beginTransaction(); User u = (User)s.get(User.class, 1); s.getTransaction().commit(); System.out.println(u.getGroup().getName()); } @Test public void testLoadUser() { testSaveGroup(); Session s = sessionFactory.getCurrentSession(); s.beginTransaction(); User u = (User)s.load(User.class, 1); System.out.println(u.getGroup().getName()); s.getTransaction().commit(); } @Test public void testDeleteUser() { testSaveGroup(); Session s = sessionFactory.getCurrentSession(); s.beginTransaction(); //User u = (User)s.load(User.class, 1); //u.setGroup(null); //s.delete(u); s.createQuery("delete from User u where u.id = 1").executeUpdate(); s.getTransaction().commit(); } @Test public void testDeleteGroup() { testSaveGroup(); Session s = sessionFactory.getCurrentSession(); s.beginTransaction(); //User u = (User)s.load(User.class, 1); //u.setGroup(null); //s.delete(u); Group g = (Group)s.load(Group.class, 1); s.delete(g); //s.createQuery("delete from User u where u.id = 1").executeUpdate(); s.getTransaction().commit(); } @Test public void testUpdateUser() { testSaveGroup(); Session s = sessionFactory.getCurrentSession(); s.beginTransaction(); User u = (User)s.get(User.class, 1); s.getTransaction().commit(); u.setName("user"); u.getGroup().setName("group"); Session s2 = sessionFactory.getCurrentSession(); s2.beginTransaction(); s2.update(u); s2.getTransaction().commit(); } @Test public void testGetGroup() { testSaveGroup(); Session s = sessionFactory.getCurrentSession(); s.beginTransaction(); Group g = (Group)s.get(Group.class, 1); s.getTransaction().commit(); for(User u : g.getUsers()) { System.out.println(u.getName()); } } @Test public void testSchemaExport() { new SchemaExport(new AnnotationConfiguration().configure()).create(false, true); } public static void main(String[] args) { beforeClass(); } }
二.存group
1.程序在上面找就是测试函数不同
三.注意
fetch用于查找同步，cascade用于增删改同步
