hibernate 复合主键
hibernate复合主键
在实体中可以定义一个嵌入式组件(embeddedcomponent),甚至覆盖该实体中原有的列映射.组件类必须在类一级定义@Embeddable注解.
在特定的实体的关联属性上使用@Embedded和@AttributeOverride注解可以覆盖该属性对应的嵌入式对象的列映射:
作为嵌入式主键类，要满足以下几点要求。
必须实现Serializable接口、必须有默认的public无参数的构造方法、必须覆盖equals和hashCode方法，这些要求与使用复合主键的要求相同。
将嵌入式主键类使用@Embeddable标注，表示这个是一个嵌入式类。
//方法1
importjavax.persistence.Embeddable;
@Embeddable
publicclassDemoPK1implementsSerializable{
privatestaticfinallongserialVersionUID=-3304319243957837925L;
privatelongid;
privateStringname;
publiclonggetId(){
returnid;
}
publicvoidsetId(longid){
this.id=id;
}
publicStringgetName(){
returnname;
}
publicvoidsetName(Stringname){
this.name=name;
}
@Override
publicbooleanequals(Objecto){
if(oinstanceofDemoPK1){
DemoPK1key=(DemoPK1)o;
if(this.id==key.getId()&&this.name.equals(key.getName())){
returntrue;
}
}
returnfalse;
}
@Override
publicinthashCode(){
returnthis.name.hashCode();
}
}
@Entity
@Table(name="Test")
publicclassDemo1implementsSerializable{
{
privateStringemail;
privateStringphone;
privateStringDemoPK1pk;
@Id
publicDemoPK1getPk(){
returnpk;
}
publicvoidsetPk(DemoPK1pk1){
this.pk=pk1;
}
@Column(name="phone",length=20)
publicStringgetPhone(){
returnphone;
}
publicvoidsetPhone(Stringphone){
this.phone=phone;
}
@Column(name="email",length=23)
publicStringgetEmail(){
returnemail;
}
publicvoidsetEmail(Stringemail){
this.email=email;
}
//省略getset方法注视
}
//方法2
publicclassDemoPK2implementsSerializable{
privatestaticfinallongserialVersionUID=-3304319243957837925L;
privatelongid;
privateStringname;
publiclonggetId(){
returnid;
}
publicvoidsetId(longid){
this.id=id;
}
publicStringgetName(){
returnname;
}
publicvoidsetName(Stringname){
this.name=name;
}
@Override
publicbooleanequals(Objecto){
if(oinstanceofDemoPK2){
DemoPK2key=(DemoPK2)o;
if(this.id==key.getId()&&this.name.equals(key.getName())){
returntrue;
}
}
returnfalse;
}
@Override
publicinthashCode(){
returnthis.name.hashCode();
}
}
@Entity
@Table(name="Test")
publicclassDemo2implementsSerializable{
{
privateStringemail;
privateStringphone;
privateStringDemoPK2pk;
@EmbeddedId
publicDemoPK2getPk(){
returnpk;
}
publicvoidsetPk(DemoPK2pk1){
this.pk=pk1;
}
@Column(name="phone",length=20)
publicStringgetPhone(){
returnphone;
}
publicvoidsetPhone(Stringphone){
this.phone=phone;
}
@Column(name="email",length=23)
publicStringgetEmail(){
returnemail;
}
publicvoidsetEmail(Stringemail){
this.email=email;
}
//省略getset方法注视
}
//方法3
publicclassDemoPK3implementsSerializable{
privatestaticfinallongserialVersionUID=-3304319243957837925L;
privatelongid;
privateStringname;
publiclonggetId(){
returnid;
}
publicvoidsetId(longid){
this.id=id;
}
publicStringgetName(){
returnname;
}
publicvoidsetName(Stringname){
this.name=name;
}
@Override
publicbooleanequals(Objecto){
if(oinstanceofDemoPK3){
DemoPK3key=(DemoPK3)o;
if(this.id==key.getId()&&this.name.equals(key.getName())){
returntrue;
}
}
returnfalse;
}
@Override
publicinthashCode(){
returnthis.name.hashCode();
}
}
@Entity
@Table(name="Test")
@IdClass(DemoPK3.class)
publicclassDemo3{
privateStringemail;
privateStringphone;
@Column(name="phone",length=20)
publicStringgetPhone(){
returnphone;
}
publicvoidsetPhone(Stringphone){
this.phone=phone;
}
@Column(name="email",length=23)
publicStringgetEmail(){
returnemail;
}
publicvoidsetEmail(Stringemail){
this.email=email;
}
}
下面看下配置文件：
<?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/hibernate</property>
<propertyname="connection.username">root</property>
<propertyname="connection.password">root</property>
<propertyname="connection.pool_size">100</property>
<propertyname="dialect">org.hibernate.dialect.MySQLDialect</property>
<propertyname="current_session_context_class">thread</property>
<propertyname="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<propertyname="show_sql">true</property>
<propertyname="format_sql">true</property>
<!--Dropandre-createthedatabaseschemaonstartup-->
<!--<propertyname="hbm2ddl.auto">create</property>-->
<mappingclass="com.Demo1"/>
<mappingclass="com.Demo2"/>
<mappingclass="com.Demo3"/>
</session-factory>
</hibernate-configuration>
//参考连接：
http://blog.csdn.net/ly5156/article/details/6755585JPA实体的注解规范以及Hibernate特有的扩展
//测试代码：
criteria.addOrder(Order.desc("pk.id"));//对符合主键排序注意的地方
criteria.addOrder(Order.desc("pk.name"));
Listlist=criteria.list();