hibernate insert 时 无主键使用复合主键

复合主键，由多个字段组成主键，例如，使用一个用户的firstname和lastname组成主键。

可以通过两种方式确定主键，一种是基于实体类的复合主键，另一种是通过定义主键类来实现。
不管通过哪种方式，复合主键都需要实现equals方法和hashcode方法，以作为不同数据之间是别的标志。

一.基于实体类属性的复合主键
主键由实体类中的属性组成。

1.映射文件TUser.hbm.xml

xml 代码

<? 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 = "cn.blogjava.start.TUser"   table = "t_user"   catalog = "sample" >
          < composite-id >
              < key-property   name = "lastname"   column = "lastname"   type = "string"   />
              < key-property   name = "firstname"   column = "firstname"   type = "string"   />
          </ composite-id >

          < property   name = "age"   type = "integer"   column = "age" />
      </ class >
  </ hibernate-mapping >

2.TUser.java

java 代码

package  cn.blogjava.start;

  import  org.apache.commons.lang.builder.EqualsBuilder;
  import  org.apache.commons.lang.builder.HashCodeBuilder;

  /**
 * TUser generated by hbm2java
 */

  public   class  TUser  implements  java.io.Serializable {

      // Fields

      private  Integer age;

      private  String firstname;

      private  String lastname;

      public  Integer getAge() {
          return  age;
    }

      public   void  setAge(Integer age) {
          this .age = age;
    }

      public  String getFirstname() {
          return  firstname;
    }

      public   void  setFirstname(String firstname) {
          this .firstname = firstname;
    }

      public  String getLastname() {
          return  lastname;
    }

      public   void  setLastname(String lastname) {
          this .lastname = lastname;
    }

      public   boolean  equals(Object obj) {
          if (!(obj  instanceof  TUser)) {
              return   false ;
        }

        TUser user = (TUser)obj;
          return   new  EqualsBuilder()           // EqualsBuilder 和HashCodeBuilder均为apache common lang包中的工具类
             .appendSuper( super .equals(obj))
             .append( this .lastname, user.lastname)
             .append( this .firstname, user.firstname)
            .isEquals();
    }

      public   int  hasCode() {
          return   new  HashCodeBuilder(- 528253723 , - 475504089 )
             .appendSuper( super .hashCode())
             .append( this .lastname).append( this .firstname)
            .toHashCode();

    }

}

3.测试类HibernateTest.java

java 代码

 

package  cn.blogjava.start;

  import  junit.framework.Assert;
  import  junit.framework.TestCase;

  import  org.hibernate.HibernateException;
  import  org.hibernate.Session;
  import  org.hibernate.SessionFactory;
  import  org.hibernate.Transaction;
  import  org.hibernate.cfg.Configuration;


  public   class  HibernateTest  extends  TestCase {

     Session session =  null ;
      /**
     * JUnit中的setUp方法在TestCase初始化的时候会自动调用
     * 一般用于初始化公用资源
     */
      protected   void  setUp() {
          try  {
              /**
             * 可以采用hibernate.properties或者hibernate.cfg.xml
             * 配置文件的初始化代码
             *
             * 采用hibernate.properties
             * Configuration config = new Configuration()；
             * config.addClass(TUser.class);
             */

              //采用hibernate.cfg.xml配置文件，与上面的方法对比，两个差异
              //1.Configuration的初始化方式
              //2.xml
             Configuration config =  new  Configuration().configure();
            SessionFactory sessionFactory = config.buildSessionFactory();
            session = sessionFactory.openSession();

         }  catch  (HibernateException e) {
              // TODO: handle exception
            e.printStackTrace();
        }
    }

      /**
     * JUnit中的tearDown方法在TestCase执行完毕的时候会自动调用
     * 一般用于释放资源
     */
      protected   void  tearDown() {
          try  {
            session.close();
         }  catch  (HibernateException e) {
              // TODO: handle exception
            e.printStackTrace();
        }
    }

      /**
     * 对象持久化测试(Insert方法)
     */
      public   void  testInsert() {
         Transaction tran =  null ;
          try  {
            tran = session.beginTransaction();
             TUser user =  new  TUser();
             user.setFirstname( "bai" );
             user.setLastname( "yunfeng" );
             user.setAge( 26 );
            session.save(user);
            session.flush();
            tran.commit();
         }  catch  (HibernateException e) {
              // TODO: handle exception
            e.printStackTrace();
            Assert.fail(e.getMessage());
              if (tran !=  null ) {
                  try  {
                    tran.rollback();
                 }  catch  (Exception e1) {
                      // TODO: handle exception
                    e1.printStackTrace();
                }
            }
        }
    }

      /**
     * 对象读取测试(Select方法)
     */
      public   void  testSelect(){
         TUser user =  new  TUser();
         user.setFirstname( "bai" );
         user.setLastname( "yunfeng" );

         user = (TUser)session.load(TUser. class , user);
         Assert.assertEquals(user.getAge().intValue(),  26 );
    }
}

基于主键类的复合主键：
方法：将主键字段从POJO类中提出了，生成一个主键类。
可以将1中的例子加以改造，将firstname和lastname字段单独提取到一个主键类中。

1.
配置文件TUser.hbm.xml 
composite-id节点的name指定了实体类中的主键类的属性名.

xml 代码

<? 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   package = "cn.blogjava.start" >
      < class   name = "TUser"   table = "t_user"   catalog = "sample" >
          < composite-id   name = "userPK"   class = "TUserPK" >
              < key-property   name = "lastname"   column = "lastname"   type = "string"   />
              < key-property   name = "firstname"   column = "firstname"   type = "string"   />
          </ composite-id >

          < property   name = "age"   type = "integer"   column = "age" />
      </ class >
  </ hibernate-mapping >

2.POJO类

package  cn.blogjava.start;

  /**
 * TUser generated by hbm2java
 */

  public   class  TUser  implements  java.io.Serializable {

      // Fields

      private  Integer age;

      //配置文件composite-id的name属性
      private  TUserPK userPK;


      public  Integer getAge() {
          return  age;
    }

      public   void  setAge(Integer age) {
          this .age = age;
    }

      public  TUserPK getUserPK() {
          return  userPK;
    }

      public   void  setUserPK(TUserPK userPK) {
          this .userPK = userPK;
    }
}

3.主键类TUserPK.java

java 代码

package  cn.blogjava.start;

  import  java.io.Serializable;

  import  org.apache.commons.lang.builder.EqualsBuilder;
  import  org.apache.commons.lang.builder.HashCodeBuilder;

  public   class  TUserPK  implements  Serializable {

      private  String firstname;
      private  String lastname;

      public  String getFirstname() {
          return  firstname;
    }

      public   void  setFirstname(String firstname) {
          this .firstname = firstname;
    }

      public  String getLastname() {
          return  lastname;
    }

      public   void  setLastname(String lastname) {
          this .lastname = lastname;
    }

      public   boolean  equals(Object obj) {
          if (!(obj  instanceof  TUserPK)) {
              return   false ;
        }

        TUserPK userPK = (TUserPK)obj;
          return   new  EqualsBuilder()
             .appendSuper( super .equals(obj))
             .append( this .lastname, userPK.lastname)
             .append( this .firstname, userPK.firstname)
            .isEquals();
    }

      public   int  hasCode() {
          return   new  HashCodeBuilder(- 528253723 , - 475504089 )
             .appendSuper( super .hashCode())
             .append( this .lastname).append( this .firstname)
            .toHashCode();
    }
}

4.测试代码HibernateTest.java

java 代码

 

package  cn.blogjava.start;

  import  junit.framework.Assert;
  import  junit.framework.TestCase;

  import  org.hibernate.HibernateException;
  import  org.hibernate.Session;
  import  org.hibernate.SessionFactory;
  import  org.hibernate.Transaction;
  import  org.hibernate.cfg.Configuration;


  public   class  HibernateTest  extends  TestCase {

     Session session =  null ;
      /**
     * JUnit中的setUp方法在TestCase初始化的时候会自动调用
     * 一般用于初始化公用资源
     */
      protected   void  setUp() {
          try  {
              /**
             * 可以采用hibernate.properties或者hibernate.cfg.xml
             * 配置文件的初始化代码
             *
             * 采用hibernate.properties
             * Configuration config = new Configuration()；
             * config.addClass(TUser.class);
             */

              //采用hibernate.cfg.xml配置文件，与上面的方法对比，两个差异
              //1.Configuration的初始化方式
              //2.xml
             Configuration config =  new  Configuration().configure();
            SessionFactory sessionFactory = config.buildSessionFactory();
            session = sessionFactory.openSession();

         }  catch  (HibernateException e) {
              // TODO: handle exception
            e.printStackTrace();
        }
    }

      /**
     * JUnit中的tearDown方法在TestCase执行完毕的时候会自动调用
     * 一般用于释放资源
     */
      protected   void  tearDown() {
          try  {
            session.close();
         }  catch  (HibernateException e) {
              // TODO: handle exception
            e.printStackTrace();
        }
    }

      /**
     * 对象持久化测试(Insert方法)
     */
      public   void  testInsert() {
         Transaction tran =  null ;
          try  {
            tran = session.beginTransaction();
             TUser user =  new  TUser();
             TUserPK userPK =  new  TUserPK();
             userPK.setFirstname( "yu" );
             userPK.setLastname( "yy" );
            user.setUserPK(userPK);
             user.setAge( 25 );
            session.save(user);
            session.flush();
            tran.commit();
         }  catch  (HibernateException e) {
              // TODO: handle exception
            e.printStackTrace();
            Assert.fail(e.getMessage());
              if (tran !=  null ) {
                  try  {
                    tran.rollback();
                 }  catch  (Exception e1) {
                      // TODO: handle exception
                    e1.printStackTrace();
                }
            }
        }
    }

      /**
     * 对象读取测试(Select方法)
     */
      public   void  testSelect(){
         TUserPK userPK =  new  TUserPK();
         userPK.setFirstname( "yu" );
         userPK.setLastname( "yy" );

         TUser user = (TUser)session.load(TUser. class , userPK);
         Assert.assertEquals(user.getAge().intValue(),  25 );
    }
}