Hibernate----@Annotation----一对多----级联

一对多,双向,"一"的一方

 packagecom.pegasus.domain;

 importjava.util.HashSet;
 importjava.util.Set;

 importjavax.persistence.CascadeType;
 importjavax.persistence.Entity;
 importjavax.persistence.FetchType;
 importjavax.persistence.GeneratedValue;
 importjavax.persistence.Id;
 importjavax.persistence.JoinColumn;
 importjavax.persistence.OneToMany;
 importjavax.persistence.Table;

 //在实体类的类名前
 //标注是实体
 //对应的表名
 //相当于xml的
 //<classname="com.pegasus.domain.Group"table="t_group"></class>
 @Entity
 @Table(name="t_group")
 publicclassGroup{
 privateintid;
 privateStringname;
 privateSet<User>users=newHashSet<User>();

 //在主键的get方法前
 //标注主键,以及生成主键策略
 //相当于<idname="id"><generatorclass="native"></generator></id>
 @Id
 @GeneratedValue
 publicintgetId(){
 returnid;
 }
 publicvoidsetId(intid){
 this.id=id;
 }

 //在一般属性的get方法前
 //一般的列名前不需要标注
 //相当于<propertyname="name"></property>
 publicStringgetName(){
 returnname;
 }
 publicvoidsetName(Stringname){
 this.name=name;
 }

 //在一对多"一"的一方关联的集合前
 //使用@OneToMany标注,并标明"mappedBy",即关联的"多"的一方所对应的类的属性
 //cascade参数标明级联的方式,如果不需要级联可以省略
 //相当于<setname="users">
 //<keycolumn="groupId"></key>
 //<one-to-manyclass="com.pegasus.domain.User"/>
 //</set>
 @OneToMany(mappedBy="group",
 cascade={CascadeType.ALL}
 )

 publicSet<User>getUsers(){
 returnusers;
 }
 publicvoidsetUsers(Set<User>users){
 this.users=users;
 }
 }

一对多,双向,"多"的一方

 packagecom.pegasus.domain;

 importjavax.persistence.CascadeType;
 importjavax.persistence.Entity;
 importjavax.persistence.FetchType;
 importjavax.persistence.GeneratedValue;
 importjavax.persistence.Id;
 importjavax.persistence.ManyToOne;
 importjavax.persistence.Table;
 //在实体类的类名前
 //标注是实体
 //对应的表名
 //相当于xml的
 //<classname="com.pegasus.domain.User"table="t_user"></class>
 @Entity
 @Table(name="t_user")
 publicclassUser{
 privateintid;
 privateStringname;
 privateGroupgroup;

 //在主键的get方法前
 //标注主键,以及生成主键策略
 //相当于<idname="id"><generatorclass="native"></generator></id>
 @Id
 @GeneratedValue
 publicintgetId(){
 returnid;
 }
 publicvoidsetId(intid){
 this.id=id;
 }

 //在一般属性的get方法前
 //一般的列名前不需要标注
 //相当于<propertyname="name"></property>
 publicStringgetName(){
 returnname;
 }
 publicvoidsetName(Stringname){
 this.name=name;
 }
 //在一对多"多"的一方关联的属性get方法前
 //使用@ManyToOne标注
 //cascade参数标明级联的方式,如果不需要级联可以省略
 //相当于<many-to-onename="group"column="groupId"></many-to-one>
 @ManyToOne(cascade={CascadeType.ALL})
 publicGroupgetGroup(){
 returngroup;
 }
 publicvoidsetGroup(Groupgroup){
 this.group=group;
 }
 }

单元测试类

 packagecom.pegasus.domain;

 importorg.hibernate.Session;
 importorg.hibernate.SessionFactory;
 importorg.hibernate.cfg.AnnotationConfiguration;
 importorg.hibernate.tool.hbm2ddl.SchemaExport;
 importorg.junit.AfterClass;
 importorg.junit.BeforeClass;
 importorg.junit.Test;

 publicclassHibernateORMappingTest{
 privatestaticSessionFactorysessionFactory;

 @BeforeClass
 publicstaticvoidbeforeClass(){
 newSchemaExport(newAnnotationConfiguration().configure()).create(false,true);
 sessionFactory=newAnnotationConfiguration().configure().buildSessionFactory();
 }
 @AfterClass
 publicstaticvoidafterClass(){
 sessionFactory.close();
 }
 /**级联保存*/
 @Test
 publicvoidtestSaveUser(){
 System.out.print("begintotestSaveUser()");
 Useru=newUser();
 u.setName("u1");
 Groupg=newGroup();
 g.setName("g1");
 u.setGroup(g);
 Sessions=sessionFactory.getCurrentSession();
 s.beginTransaction();
 //s.save(g);
 s.save(u);
 s.getTransaction().commit();
 }

 //@Test
 //publicvoidtestSaveGroup(){
 //System.out.print("begintotestSaveGroup()");
 //Useru1=newUser();
 //u1.setName("u1");
 //Useru2=newUser();
 //u2.setName("u2");
 //Groupg=newGroup();
 //g.setName("g1");
 //g.getUsers().add(u1);
 //g.getUsers().add(u2);
 //u1.setGroup(g);
 //u2.setGroup(g);
 //Sessions=sessionFactory.getCurrentSession();
 //s.beginTransaction();
 //s.save(g);
 //s.getTransaction().commit();
 //}
 /**级联查询*/
 @Test
 publicvoidtestGetUser(){
 System.out.print("begintotestGetUser()");
 //testSaveGroup();

 Sessions=sessionFactory.getCurrentSession();
 s.beginTransaction();
 Useru=(User)s.get(User.class,1);

 s.getTransaction().commit();
 System.out.println(u.getGroup().getName());
 }

 //@Test
 //publicvoidtestDeleteUser(){
 //System.out.print("begintotestDeleteUser()");
 //testSaveGroup();
 //
 //Sessions=sessionFactory.getCurrentSession();
 //s.beginTransaction();
 ////Useru=(User)s.load(User.class,1);
 ////u.setGroup(null);
 ////s.delete(u);
 //s.createQuery("deletefromUseruwhereu.id=1").executeUpdate();
 //s.getTransaction().commit();
 //
 //}

 /**级联修改*/
 @Test
 publicvoidtestUpdateUser(){
 System.out.print("begintotestUpdateUser()");
 //testSaveGroup();

 Sessions=sessionFactory.getCurrentSession();
 s.beginTransaction();
 Useru=(User)s.get(User.class,1);

 s.getTransaction().commit();

 u.setName("user");
 u.getGroup().setName("group");

 Sessions2=sessionFactory.getCurrentSession();
 s2.beginTransaction();
 s2.update(u);

 s2.getTransaction().commit();
 }

 /**级联删除*/
 @Test
 publicvoidtestDeleteGroup(){
 System.out.print("begintotestDeleteGroup()");
 testSaveGroup();

 Sessions=sessionFactory.getCurrentSession();
 s.beginTransaction();
 //Useru=(User)s.load(User.class,1);
 //u.setGroup(null);
 //s.delete(u);
 Groupg=(Group)s.load(Group.class,1);
 s.delete(g);
 //s.createQuery("deletefromUseruwhereu.id=1").executeUpdate();
 s.getTransaction().commit();

 }


 //@Test
 //publicvoidtestSchemaExport(){
 //newSchemaExport(newAnnotationConfiguration().configure()).create(true,true);
 //}

 //publicstaticvoidmain(String[]args){
 //beforeClass();
 //}
 }

hibernate.cfg.xml

 <?xmlversion='1.0'encoding='utf-8'?>
 <!DOCTYPEhibernate-configurationPUBLIC
 "-//Hibernate/HibernateConfigurationDTD3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

 <hibernate-configuration>

 <session-factory>


 <propertyname="connection.driver_class">com.mysql.jdbc.Driver</property>
 <propertyname="connection.url">jdbc:mysql://localhost/hibtest</property>
 <propertyname="connection.username">root</property>
 <propertyname="connection.password">123</property>
 <propertyname="dialect">org.hibernate.dialect.MySQLDialect</property>

 <!--JDBCconnectionpool(usethebuilt-in)-->
 <propertyname="connection.pool_size">1</property>

 <!--EnableHibernate'sautomaticsessioncontextmanagement-->
 <propertyname="current_session_context_class">thread</property>

 <!--Disablethesecond-levelcache-->
 <propertyname="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

 <!--EchoallexecutedSQLtostdout-->
 <propertyname="show_sql">true</property>
 <!--<propertyname="format_sql">true</property>-->

 <!--Dropandre-createthedatabaseschemaonstartup
 <propertyname="hbm2ddl.auto">update</property>
 -->
 <!--

 <mappingresource="com/pegasus/domain/Group.hbm.xml"/>
 <mappingresource="com/pegasus/domain/User.hbm.xml"/>
 -->
 <mappingclass="com.pegasus.domain.Group"/>
 <mappingclass="com.pegasus.domain.User"/>

 </session-factory>

 </hibernate-configuration>