Oracle使用MyBatis中RowBounds实现分页查询功能

package com.xyfer.service.impl;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.session.RowBounds;
import com.xyfer.dao.UserDao;
import com.xyfer.service.UserService;
public class UserServiceImpl implements UserService {
  private UserDao userDao;
  @Override
  public Map<String, Object> queryUserList(String currentPage, String pageSize) {
    //查询数据总条数
    int total = userDao.queryCountUser();
    //返回结果集
    Map<String,Object> resultMap = new HashMap<String,Object>();
    resultMap.put("total", total);
    //总页数
    int totalpage = (total + Integer.parseInt(pageSize) - 1) / Integer.parseInt(pageSize);
    resultMap.put("totalpage", totalpage);
    //数据的起始行
    int offset = (Integer.parseInt(currentPage)-1)*Integer.parseInt(pageSize);
    RowBounds rowbounds = new RowBounds(offset, Integer.parseInt(pageSize));
    //用户数据集合
    List<Map<String, Object userList = userDao.queryUserList(rowbounds);
    resultMap.put("userList", userList);
    return resultMap;
  }
}

package com.xyfer.dao;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.session.RowBounds;
public interface UserDao {
  public int queryCountUser();    //查询用户总数
  public List<Map<String, Object queryUserList(RowBounds rowbounds);  //查询用户列表
}

<"1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.xyfer.mapper.UserMapper">
  <!-- 查询用户总数 -->
  <select id="queryCountUser" resultType="java.lang.Integer">
    select count(1) from user
  </select>
  <!-- 查询用户列表 -->
  <select id="queryUserList" resultType="java.util.Map">
    select * from user
  </select>
</mapper>