Hibernate UserType 自定义类型

转自 :http://www.iteye.com/topic/182797

 

 仔细看看hibernate的DOC发现不少惊奇的东东,后悔自己的旁门助道是多么的无用. 本次主要实现目的. 数据库表:EchoMessageEmail,其中有三个字段id(自动编号)\name\Email(varchar) 实现目的:数据库字段中Email的值是类似于[email protected];www.1718zx.cn的.所以要求以List表达.也就是生成的DataModel当中是有一个List对象的.hbm.xml

xml 代码

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!--
    Mapping file autogenerated by MyEclipse - Hibernate Tools
-->
<hibernate-mapping>
    <class name="com.travelsky.hibernate.po.EchoMessageEmail" table="echo_message_email">
        <id name="id" type="java.lang.Integer">
            <column name="ID" />
            <generator class="native"></generator>
        </id>
        <property name="name" type="java.lang.String">
            <column name="NAME" length="50" not-null="true" />
        </property>
        <property name="email" type="com.travelsky.hibernate.po.EmailList" lazy="true">
            <column name="EMAIL"/>
        </property>
    </class>
</hibernate-mapping>

<?xml version="1.0" encoding="utf-8"?>   
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"   
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">   
<!--   
    Mapping file autogenerated by MyEclipse - Hibernate Tools  
-->   
<hibernate-mapping>   
    <class name="com.travelsky.hibernate.po.EchoMessageEmail" table="echo_message_email">   
        <id name="id" type="java.lang.Integer">   
            <column name="ID" />   
            <generator class="native"></generator>   
        </id>   
        <property name="name" type="java.lang.String">   
            <column name="NAME" length="50" not-null="true" />   
        </property>   
        <property name="email" type="com.travelsky.hibernate.po.EmailList" lazy="true">   
            <column name="EMAIL"/>              
        </property>           
    </class>   
</hibernate-mapping>  

对应的POJO:

java 代码

package com.travelsky.hibernate.po;
import java.util.List;

/**
 * EchoMessageEmail generated by MyEclipse Persistence Tools
 */

public class EchoMessageEmail  implements java.io.Serializable {

     private Integer id;
     private String name;
     private List email;

    /** default constructor */
    public EchoMessageEmail() {
    }

    /** minimal constructor */
    public EchoMessageEmail(String name) {
        this.name = name;
    }

    /** full constructor */
    public EchoMessageEmail(String name, List email) {
        this.name = name;
        this.email = email;
    }


    // Property accessors

    public Integer getId() {
        return this.id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List getEmail() {
        return email;
    }

    public void setEmail(List email) {
        this.email = email;
    }

}

package com.travelsky.hibernate.po;   
import java.util.List;   
   
/**  
 * EchoMessageEmail generated by MyEclipse Persistence Tools  
 */   
   
public class EchoMessageEmail  implements java.io.Serializable {   
   
     private Integer id;   
     private String name;   
     private List email;   
   
    /** default constructor */   
    public EchoMessageEmail() {   
    }   
   
    /** minimal constructor */   
    public EchoMessageEmail(String name) {   
        this.name = name;   
    }   
       
    /** full constructor */   
    public EchoMessageEmail(String name, List email) {   
        this.name = name;   
        this.email = email;   
    }   
   
      
    // Property accessors   
   
    public Integer getId() {   
        return this.id;   
    }   
       
    public void setId(Integer id) {   
        this.id = id;   
    }   
   
    public String getName() {   
        return this.name;   
    }   
       
    public void setName(String name) {   
        this.name = name;   
    }   
   
    public List getEmail() {   
        return email;   
    }   
   
    public void setEmail(List email) {   
        this.email = email;   
    }   
   
}   

UserType接口各方法的详解

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import net.sf.hibernate.HibernateException;

/**
 * @author hy-he
 *
 */
public interface UserType {

 /**
  * 返回UserType所映射字段的SQL类型（java.sql.Types)
  * 返回类型为int[]，其中包含了映射个字段的SQL类型代码
  * (UserType可以映射到一个或者多个字段)
  * @return
  */
 public int[]sqlTypes();


 /**
  * UserType.nullSafeGet()所返回的自定义数据类型
  * @return
  */
 public Class returnedClass();


 /**
  * 自定义数据类型的比对方法
  * 此方法将用作脏数据检查，参数x、y分别为数据的两个副本
  * 如果equals方法返回false,则Hibernate将认为数据发生变化,并将变化更新到数据库表中
  * @param x
  * @param y
  * @return
  * @throws HibernateException
  */
 public boolean equals(Object x,Object y)throws HibernateException;


 /**
  * 从JDBC ResultSet读取数据,将其转换为自定义类型后返回
  * (此方法要求对克能出现null值进行处理)
  * names中包含了当前自定义类型的映射字段名称
  * @param rs
  * @param names
  * @param owner
  * @return
  * @throws HibernateException
  * @throws SQLException
  */
 public Object nullSafeGet(ResultSet rs,String[] names,Object owner)throws HibernateException,SQLException;


 /**
  * 本方法将在Hibernate进行数据保存时被调用
  * 我们可以通过PreparedStateme将自定义数据写入到对应的数据库表字段
  * @param st
  * @param value
  * @param index
  * @throws HibernateException
  * @throws SQLException
  */
 public void nullSafeSet(PreparedStatement st,Object value,int index)throws HibernateException,SQLException;


 /**
  * 提供自定义类型的完全复制方法
  * 本方法将用构造返回对象
  * 当nullSafeGet方法调用之后，我们获得了自定义数据对象，在向用户返回自定义数据之前，
  * deepCopy方法将被调用，它将根据自定义数据对象构造一个完全拷贝，并将此拷贝返回给用户
  * 此时我们就得到了自定义数据对象的两个版本，第一个是从数据库读出的原始版本，其二是我们通过
  * deepCopy方法构造的复制版本，原始的版本将有Hibernate维护，复制版由用户使用。原始版本用作
  * 稍后的脏数据检查依据；Hibernate将在脏数据检查过程中将两个版本的数据进行对比（通过调用
  * equals方法），如果数据发生了变化（equals方法返回false），则执行对应的持久化操作
  *
  * @param value
  * @return
  * @throws HibernateException
  */
 public Object deppCopy(Object value)throws HibernateException;


 /**
  * 本类型实例是否可变
  * @return
  */
 public boolean isMutable();
}

import java.sql.PreparedStatement;   
import java.sql.ResultSet;   
import java.sql.SQLException;   
   
import net.sf.hibernate.HibernateException;   
   
/**  
 * @author hy-he  
 *  
 */   
public interface UserType {   
   
 /**  
  * 返回UserType所映射字段的SQL类型（java.sql.Types)  
  * 返回类型为int[]，其中包含了映射个字段的SQL类型代码  
  * (UserType可以映射到一个或者多个字段)  
  * @return  
  */   
 public int[]sqlTypes();   
   
   
 /**  
  * UserType.nullSafeGet()所返回的自定义数据类型  
  * @return  
  */   
 public Class returnedClass();   
   
   
 /**  
  * 自定义数据类型的比对方法  
  * 此方法将用作脏数据检查，参数x、y分别为数据的两个副本  
  * 如果equals方法返回false,则Hibernate将认为数据发生变化,并将变化更新到数据库表中  
  * @param x  
  * @param y  
  * @return  
  * @throws HibernateException  
  */   
 public boolean equals(Object x,Object y)throws HibernateException;   
   
   
 /**  
  * 从JDBC ResultSet读取数据,将其转换为自定义类型后返回  
  * (此方法要求对克能出现null值进行处理)  
  * names中包含了当前自定义类型的映射字段名称  
  * @param rs  
  * @param names  
  * @param owner  
  * @return  
  * @throws HibernateException  
  * @throws SQLException  
  */   
 public Object nullSafeGet(ResultSet rs,String[] names,Object owner)throws HibernateException,SQLException;   
   
   
 /**  
  * 本方法将在Hibernate进行数据保存时被调用  
  * 我们可以通过PreparedStateme将自定义数据写入到对应的数据库表字段  
  * @param st  
  * @param value  
  * @param index  
  * @throws HibernateException  
  * @throws SQLException  
  */   
 public void nullSafeSet(PreparedStatement st,Object value,int index)throws HibernateException,SQLException;   
   
   
 /**  
  * 提供自定义类型的完全复制方法  
  * 本方法将用构造返回对象  
  * 当nullSafeGet方法调用之后，我们获得了自定义数据对象，在向用户返回自定义数据之前，  
  * deepCopy方法将被调用，它将根据自定义数据对象构造一个完全拷贝，并将此拷贝返回给用户  
  * 此时我们就得到了自定义数据对象的两个版本，第一个是从数据库读出的原始版本，其二是我们通过  
  * deepCopy方法构造的复制版本，原始的版本将有Hibernate维护，复制版由用户使用。原始版本用作  
  * 稍后的脏数据检查依据；Hibernate将在脏数据检查过程中将两个版本的数据进行对比（通过调用  
  * equals方法），如果数据发生了变化（equals方法返回false），则执行对应的持久化操作  
  *  
  * @param value  
  * @return  
  * @throws HibernateException  
  */   
 public Object deppCopy(Object value)throws HibernateException;   
   
   
 /**  
  * 本类型实例是否可变  
  * @return  
  */   
 public boolean isMutable();   
}   

其中的UserType的一个类:EmailList

java 代码

package com.travelsky.hibernate.po;

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.lang.StringUtils;
import org.hibernate.HibernateException;
import org.hibernate.Hibernate;

/**
 * 必须得引用java.io.Serializable,UserType是反序列化
 * 另外，我使用的hibernate版本是3.2，UserType从2.0到3.2有很大的差异，应该多多看看官方的doc
 *
 * @author @家军.严重注意org.hibernate.usertype.UserType,不要自己造车呀.
 *
 */
public class EmailList implements java.io.Serializable,org.hibernate.usertype.UserType{

    private List emails;

    private static final String SPLITTER = ";";

    private static final int[] TYPES = new int[] { Types.VARCHAR };

    public int[] sqlTypes() {

        return TYPES;
    }

    public Class returnedClass() {
        // TODO Auto-generated method stub
        return List.class;
    }

    public boolean equals(Object x, Object y) throws HibernateException {
        if (x == y)
            return true;
        if (x != null && y != null) {
            List xList = (List) x;
            List yList = (List) y;
            if (xList.size() != yList.size())
                return false;
            for (int i = 0; i < xList.size(); i++) {
                String str1 = (String) xList.get(i);
                String str2 = (String) yList.get(i);
                if (!str1.equals(str2))
                    return false;
            }
            return true;
        }
        return false;
    }

    public Object nullSafeGet(ResultSet rs, String[] names, Object owner)
            throws HibernateException, SQLException {
        String value = (String) Hibernate.STRING.nullSafeGet(rs, names[0]);
        if (value != null) {
            return parse(value);
        } else {
            return null;
        }
    }

    public void nullSafeSet(PreparedStatement st, Object value, int index)
            throws HibernateException, SQLException {
        System.out.println("Set method excecuted");
        if (value != null) {
            String str = assemble((List) value);
            Hibernate.STRING.nullSafeSet(st, str, index);
        } else {
            Hibernate.STRING.nullSafeSet(st, value, index);
        }

    }

    public Object deepCopy(Object value) throws HibernateException {
        List sourcelist = (List) value;
        List targetlist = new ArrayList();
        targetlist.addAll(sourcelist);
        return targetlist;
    }

    public boolean isMutable() {
        return false;
    }

    private String assemble(List emailList) {
        StringBuffer strBuf = new StringBuffer();
        for (int i = 0; i < emailList.size() - 1; i++) {
            strBuf.append(emailList.get(i)).append(SPLITTER);
        }
        strBuf.append(emailList.get(emailList.size() - 1));
        return strBuf.toString();
    }

    private List parse(String value) {
        String[] strs = StringUtils.split(value, SPLITTER);
        List emailList = new ArrayList();
        for (int i = 0; i < strs.length; i++) {
            emailList.add(strs[i]);
        }
        return emailList;
    }

    public Object assemble(Serializable arg0, Object arg1) throws HibernateException {
        // TODO Auto-generated method stub
        return null;
    }

    public Serializable disassemble(Object arg0) throws HibernateException {
        // TODO Auto-generated method stub
        return null;
    }

    public int hashCode(Object arg0) throws HibernateException {
        // TODO Auto-generated method stub
        return 0;
    }

    public Object replace(Object arg0, Object arg1, Object arg2) throws HibernateException {
        // TODO Auto-generated method stub
        return null;
    }

}

package com.travelsky.hibernate.po;   
   
import java.io.Serializable;   
import java.sql.PreparedStatement;   
import java.sql.ResultSet;   
import java.sql.SQLException;   
import java.sql.Types;   
import java.util.ArrayList;   
import java.util.List;   
   
import org.apache.commons.lang.StringUtils;   
import org.hibernate.HibernateException;   
import org.hibernate.Hibernate;   
   
/**  
 * 必须得引用java.io.Serializable,UserType是反序列化  
 * 另外，我使用的hibernate版本是3.2，UserType从2.0到3.2有很大的差异，应该多多看看官方的doc  
 *   
 * @author @家军.严重注意org.hibernate.usertype.UserType,不要自己造车呀. 
 *   
 */   
public class EmailList implements java.io.Serializable,org.hibernate.usertype.UserType{   
   
    private List emails;   
   
    private static final String SPLITTER = ";";   
   
    private static final int[] TYPES = new int[] { Types.VARCHAR };   
   
    public int[] sqlTypes() {   
           
        return TYPES;   
    }   
   
    public Class returnedClass() {   
        // TODO Auto-generated method stub   
        return List.class;   
    }   
   
    public boolean equals(Object x, Object y) throws HibernateException {   
        if (x == y)   
            return true;   
        if (x != null && y != null) {   
            List xList = (List) x;   
            List yList = (List) y;   
            if (xList.size() != yList.size())   
                return false;   
            for (int i = 0; i < xList.size(); i++) {   
                String str1 = (String) xList.get(i);   
                String str2 = (String) yList.get(i);   
                if (!str1.equals(str2))   
                    return false;   
            }   
            return true;   
        }   
        return false;   
    }   
   
    public Object nullSafeGet(ResultSet rs, String[] names, Object owner)   
            throws HibernateException, SQLException {   
        String value = (String) Hibernate.STRING.nullSafeGet(rs, names[0]);   
        if (value != null) {   
            return parse(value);   
        } else {   
            return null;   
        }   
    }   
   
    public void nullSafeSet(PreparedStatement st, Object value, int index)   
            throws HibernateException, SQLException {   
        System.out.println("Set method excecuted");   
        if (value != null) {   
            String str = assemble((List) value);   
            Hibernate.STRING.nullSafeSet(st, str, index);   
        } else {   
            Hibernate.STRING.nullSafeSet(st, value, index);   
        }   
   
    }   
   
    public Object deepCopy(Object value) throws HibernateException {   
        List sourcelist = (List) value;   
        List targetlist = new ArrayList();   
        targetlist.addAll(sourcelist);   
        return targetlist;   
    }   
   
    public boolean isMutable() {           
        return false;   
    }   
   
    private String assemble(List emailList) {   
        StringBuffer strBuf = new StringBuffer();   
        for (int i = 0; i < emailList.size() - 1; i++) {   
            strBuf.append(emailList.get(i)).append(SPLITTER);   
        }   
        strBuf.append(emailList.get(emailList.size() - 1));   
        return strBuf.toString();   
    }   
   
    private List parse(String value) {   
        String[] strs = StringUtils.split(value, SPLITTER);   
        List emailList = new ArrayList();   
        for (int i = 0; i < strs.length; i++) {   
            emailList.add(strs[i]);   
        }   
        return emailList;   
    }   
   
    public Object assemble(Serializable arg0, Object arg1) throws HibernateException {   
        // TODO Auto-generated method stub   
        return null;   
    }   
   
    public Serializable disassemble(Object arg0) throws HibernateException {   
        // TODO Auto-generated method stub   
        return null;   
    }   
   
    public int hashCode(Object arg0) throws HibernateException {   
        // TODO Auto-generated method stub   
        return 0;   
    }   
   
    public Object replace(Object arg0, Object arg1, Object arg2) throws HibernateException {   
        // TODO Auto-generated method stub   
        return null;   
    }   
   
}   

测试类:

package com.travelsky.test;
import java.util.List;
import java.util.ListIterator;
import com.travelsky.hibernate.po.EchoMessageEmail;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateTest {

    public static void main(String[] args) throws Exception{
        Configuration config = new Configuration().configure();
        SessionFactory factory = config.buildSessionFactory();
        Session session = factory.openSession();
        Query query = session.createQuery("from EchoMessageEmail as a");
        /**
         * 理论上来说,这里不存在lazy加载,为了安全起见使用了Iterator
         *
         */
        ListIterator iterator = query.list().listIterator();
        EchoMessageEmail tt = (EchoMessageEmail) iterator.next();//只找第一个
        List emails = tt.getEmail();
        for (int i = 0; i < emails.size(); i++) {
            String emailStr = (String)emails.get(i);
            System.out.println(emailStr);
        }
        session.close();
    }
}