一、UserType

Hibernate拥有自定义映射表属性的机制，主要通过实现接口UserType，具体的UserType：

import java.sql.PreparedStatement;     import java.sql.ResultSet;     import java.sql.SQLException;          import net.sf.hibernate.HibernateException;               public interface UserType {                 public int[]sqlTypes();                      public Class returnedClass();                      public boolean equals(Object x,Object y)throws HibernateException;                      public Object nullSafeGet(ResultSet rs,String[] names,Object owner)throws HibernateException,SQLException;                      public void nullSafeSet(PreparedStatement st,Object value,int index)throws HibernateException,SQLException;                      public Object deppCopy(Object value)throws HibernateException;                      public boolean isMutable();     }     

例子：一个学生有联系地址，而联系地址又分为家庭地址和工作地址，我们可以把两个地址信息抽象成一个新的Address类，作为Student的成员变量。

数据库结构：

create table typestu (id varchar(32) primary key,name varchar(32),homeaddr varchar(32),workaddr varchar(32));

Hibernate.cfg.xml

"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">





root

jdbc:mysql://localhost:3306/schoolproject?characterEncoding=gb2312&useUnicode=true


org.hibernate.dialect.MySQLDialect

mysql
1234

com.mysql.jdbc.Driver


org.hibernate.dialect.MySQLDialect

true
thread

Pojo

package Search.UserType;


public class Student {
private String id; //标识id
private String name; //学生姓名
private AddressType address;//地址
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public AddressType getAddress() {
return address;
}
public void setAddress(AddressType address) {
this.address = address;
}




}

自定义类型

package Search.UserType;

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import org.apachemons.lang.builder.EqualsBuilder;
import org.apachemons.lang.builder.HashCodeBuilder;
import org.hibernate.HibernateException;
import org.hibernate.usertype.UserType;

public class AddressType implements UserType, Serializable {
private String homeAddr;
private String workAddr;


private static final int[] SQL_TYPES = { Types.VARCHAR, Types.VARCHAR };


public int[] sqlTypes() {
return SQL_TYPES;
}


public Class returnedClass() {
return AddressType.class;
}


public boolean isMutable() {
return false;
}


public Object deepCopy(Object value) {
return value; // Address is immutable
}


public boolean equals(Object x, Object y) {
if (x == y)
return true;
if (x == null || y == null)
return false;
AddressType add1 = (AddressType) x;
AddressType add2 = (AddressType) y;
return new EqualsBuilder() //使用EqualsBuilder类来方便地进行比对
.append(add1.getHomeAddr(), add2.getHomeAddr()).append(
add2.getWorkAddr(), add2.getWorkAddr()).isEquals();
}



public int hashCode(Object x) throws HibernateException {
AddressType address = (AddressType) x;
return new HashCodeBuilder()//使用HashCodeBuilder类来方便地进行比对
.append(address.getHomeAddr()).append(address.getWorkAddr())
.toHashCode();
}


public Object nullSafeGet(ResultSet rs, String[] names, Object owner)
throws HibernateException, SQLException {
if (rs.wasNull())
return null;
String homeAddr = rs.getString(names[0]);
String schoolAddr = rs.getString(names[1]);
AddressType address = new AddressType(homeAddr, schoolAddr);
return address;
}


public void nullSafeSet(PreparedStatement st, Object value, int index)
throws HibernateException, SQLException {
AddressType address = (AddressType) value;
if (value == null) {
st.setNull(index, Types.VARCHAR);
st.setNull(index+1, Types.VARCHAR);
} else {
st.setString(index, address.getHomeAddr());
st.setString(index + 1, address.getWorkAddr());
}
System.out.println("Data has been saved! ");
}


public Serializable disassemble(Object value) throws HibernateException {
return null;
}


public Object assemble(Serializable cached, Object owner)
throws HibernateException {
// TODO 自动生成方法存根
return null;
}

public Object replace(Object original, Object target, Object owner)
throws HibernateException {
// TODO 自动生成方法存根
return null;
}

public AddressType() {
super();
}

public AddressType(String homeAddr, String workAddr) {
super();
this.homeAddr = homeAddr;
this.workAddr = workAddr;
}


public static int[] getSQL_TYPES() {
return SQL_TYPES;
}


public String getHomeAddr() {
return homeAddr;
}


private void setHomeAddr(String homeAddr) {
this.homeAddr = homeAddr;
}

private String getWorkAddr() {
return workAddr;
}

private void setWorkAddr(String workAddr) {
this.workAddr = workAddr;
}





}

Student.hbm.xml

"hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

测试代码：

package Search.UserType;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.Blob;
import java.sql.Clob;

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

public class Test {


public static void main(String[] args) {
String filePath=System.getProperty("user.dir")+File.separator+"src/Search/UserType"+File.separator+"hibernate.cfg.xml";
File file=new File(filePath);
SessionFactory sessionFactory=new Configuration().configure(file).buildSessionFactory();
Session session=sessionFactory.openSession();
Transaction tx=session.beginTransaction();
AddressType address=new AddressType("home","work");
Student stu=new Student();
stu.setName("tome1");
stu.setAddress(address);
session.save(stu);
txmit();



}

}
二、CompositeUserType

CompositeUserType拥有UserType所有的接口，并提供了更加丰富的功能，可以实现更加复杂的功能。

待续...