Hibernate对无主键表的操作

Db2 表:Test 只有一个测试字段:name character(10)

Hibernate的hbm文件:Test.hbm.xml

<xml version="1.0"?>   
<hibernate-mapping>   
 <class name="Test" table="test">   
  <composite-id name="testpk" class="Testpk" unsaved-value="any">     
  <key-property name="name" column="name" type="string"/>     
    composite-id>     
 <class>   
hibernate-mapping>   

 Test.java

import java.io.Serializable;

public class Test implements Serializable{

 private Testpk testpk;
 
 public void setTestpk(Testpk value){
  this.testpk=value;
 }
 
 public Testpk getTestpk(){
  return this.testpk;
 }
 
}


Testpk.java

import java.io.Serializable; 

public class Testpk implements Serializable{
 
 private String name;
 public String getName()
 {
  return this.name;
 }
 
 public void setName(String value){
  this.name=value;
 }
 
 public boolean equals(Object other) { 
      Testpk that = (Testpk) other; 
     
      return this.name.equals(that.name); 
      } 
    
      /** 
    * Returns the hash code for the key. 
    */
  
      public int hashCode() { 
     
      return (this.name.hashCode());
      
      } 

}

 

测试代码：

Test t=new Test();
  Testpk tpk=new Testpk();
  tpk.setName("test000000");
  t.setTestpk(tpk);
  session.save(t);

 

最后值得注意的是当要load的时候，不能简单的Test t=(Test)session.load(Test.class,"test000000"); 而使用一个Testpk作为一个实体类的标识符。

所以应该这么写:

Testpk tpk=new Testpk();
 tpk.setName("test000000");
 Test t=(Test)session.load(Test.class,tpk);