hibernate 自定义数据类型（参考夏昕老师的《深入浅出Hibernate》）

package com.shz.usertype;

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.Hibernate;
import org.hibernate.HibernateException;
import org.hibernate.usertype.UserType;

public class EmailListType implements UserType {

 private List emails = null;

 private static final char SPLITTER = ';';

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

 @Override
 public Object assemble(Serializable cached, Object owner)
   throws HibernateException {
  return null;
 }

 public Object deepCopy(Object value) throws HibernateException {
  // 创建一个List实例，包含原有List实例的所有元素
  List sourceList = (List) value;
  List targetList = new ArrayList();
  targetList.addAll(sourceList);
  return targetList;
 }

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

 public boolean equals(Object x, Object y) throws HibernateException {
  // 判断email list是否改变
  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 s1 = (String) xList.get(i);
    String s2 = (String) yList.get(i);
    if (!s1.equals(s2)) {
     return false;
    }
   }
   return true;
  }
  return false;
 }

 public int hashCode(Object x) throws HibernateException {
  return x.hashCode();
 }

 public boolean isMutable() {
  return false;
 }

 public Object nullSafeGet(ResultSet rs, String[] names, Object owner)
   throws HibernateException, SQLException {
  // 从resultSet中取出email字段，并将其解析为List类型返回
  String value = (String) Hibernate.STRING.nullSafeGet(rs, names[0]);
  if (value != null) {
   return parse(value);
  } else {
   return null;
  }
 }

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

 private String assemble(List emailList) {
  // 将string拼装成一个字符串，以“;”分割
  StringBuffer strBuffer = new StringBuffer();
  for (int i = 0; i < emailList.size() - 1; i++) {
   strBuffer.append(emailList.get(i)).append(SPLITTER);
  }
  strBuffer.append(emailList.get(emailList.size() - 1));
  return strBuffer.toString();
 }

 public Object replace(Object original, Object target, Object owner)
   throws HibernateException {
  return null;
 }

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

 @Override
 public int[] sqlTypes() {
  return TYPES;
 }

}