mybatis分页

一、mybatis两种分页实现:

　　a):将分页方法中的当前页、和一页显示的记录数封装到Map中　　

public List<User> selectAllUsersByPage(int currentPage, int pageSize) {
        SqlSession sqlSession=null;
        List<User> userList = null;
        try {
            sqlSession = MyBatisUtils.getSqlSesion("mybatis/mybatis.xml");
            Map<String, Integer> map = new HashMap<String,Integer>();
            map.put("index", (currentPage-1)*pageSize);
            map.put("pageSize", pageSize);
            userList = sqlSession.selectList("edu.aeon.mybatis.entity.UserMapper.selectAllUsersByPage",map);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return userList;
    }

<select id="selectAllUsersByPage"  resultType="User" parameterType="java.util.Map">
     select uid,uname,upw from user limit #{index},#{pageSize}
 </select>

测试代码:

public static void testSelectAllUsersByPage(){
        UserDao userDao =new UserDaoImpl();
        List<User> userList = userDao.selectAllUsersByPage(1,2);
        for(User user:userList){
            System.out.println(user);
        }
    }

　　b):通过RowBounds实现、这种方式实现分页无需修改查询SQL语句　　

public List<User> selectAllUsersByPage1(int currentPage, int pageSize) {
        SqlSession sqlSession=null;
        List<User> userList = null;
        try {
            sqlSession = MyBatisUtils.getSqlSesion("mybatis/mybatis.xml");
            RowBounds rowBounds = new RowBounds((currentPage-1)*pageSize,pageSize);
            userList = sqlSession.selectList("edu.aeon.mybatis.entity.UserMapper.selectAllUsers",null,rowBounds);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return userList;
    }  

<select id="selectAllUsers" resultType="User">
     select uid,uname,upw from user
 </select>

测试代码：

public static void testSelectAllUsersByPage1(){
        UserDao userDao =new UserDaoImpl();
        List<User> userList = userDao.selectAllUsersByPage1(1,2);
        for(User user:userList){
            System.out.println(user);
        }
    }

当然还有另外一种就是自己封装个page类，既然我们能用更简单的方式去实现同样的功能，为什么我们还要去多此一举呢？我认为没必要！所以此处我将分页分为两种！

注解分页：

package edu.aeon.mybatis.dao;
import java.util.List;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import edu.aeon.mybatis.entity.User;
public interface UserDao {
    @Insert("insert into user(uname,upw) values(#{uname},#{upw})")
    int add(User user);
    @Delete("delete from user where uid=#{uid}")
    int delete(int uid);
    @Update("update user set uname=#{uname},upw=#{upw} where uid=#{uid}")
    int update(User user);
    @Select("select uid,uname,upw from user where uid=#{uid}")
    User selectUserById(int uid);
    @Select("select uid,uname,upw from user")
    List<User> selectAllUsers();
    @Select("select uid,uname,upw from user limit #{index},#{pageSize}")
    List<User> selectAllUsersByPage(@Param("index")int currentPage,@Param("pageSize")int pageSize);
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
 PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<properties resource="database/database_mysql.properties"/>
<typeAliases>
    <!-- 
    目的:简化配置文件的繁琐性、以前由包名+类名的形式均可变成所指定的别名类型、或者通过包名所配置后的类类型
    -->
    <!-- 第一种方式:为type属性中的内容指定引用别名为alias中的内容、指定之后所有关于type中的类型均可由alias内容代替 -->
    <!-- <typeAlias type="edu.aeon.mybatis.entity.User" alias="User"/> -->
    <!-- 第二种方式:通过包名配置、配置后所有该包下的类型均可有类名代替、不需要由以前的包名+类名的形式 -->
    <package name="edu.aeon.mybatis.entity"/>
</typeAliases>
 <environments default="development">
 <environment id="development">
 <transactionManager type="JDBC"/>
 <dataSource type="POOLED">
 <property name="driver" value="${driver}"/>
 <property name="url" value="${url}"/>
 <property name="username" value="${username}"/>
 <property name="password" value="${password}"/>
 </dataSource>
 </environment>
 </environments>
 <mappers>
<!--此处需注意-->
 <mapper class="edu.aeon.mybatis.dao.UserDao"/>
 </mappers>
</configuration>

package edu.aeon.mybatis.test;

import java.io.IOException;
import java.util.List;

import org.apache.ibatis.session.SqlSession;

import edu.aeon.mybatis.dao.UserDao;
import edu.aeon.mybatis.entity.User;
import edu.aeon.mybatis.utils.MyBatisUtils;

public class Test {
    public static void testInsertUser(){
        try {
            SqlSession sqlSession = MyBatisUtils.getSqlSesion("mybatis/mybatis.xml");
            UserDao userDao = sqlSession.getMapper(UserDao.class);
            User user = new User();
            user.setUname("testAnnotation");
            user.setUpw("testAnnotation");
            int flag = userDao.add(user);
            sqlSession.commit();
            if(flag>0){
                System.out.println("插入数据成功！");
            }else{
                System.out.println("插入数据失败！");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public static void testdeleteUserById(){
        try {
            SqlSession sqlSession = MyBatisUtils.getSqlSesion("mybatis/mybatis.xml");
            UserDao userDao = sqlSession.getMapper(UserDao.class);
            int flag = userDao.delete(5);
            sqlSession.commit();
            if(flag>0){
                System.out.println("删除数据成功！");
            }else{
                System.out.println("删除数据失败！");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public static void testUpdateUserById(int uid){
        try {
            SqlSession sqlSession = MyBatisUtils.getSqlSesion("mybatis/mybatis.xml");
            UserDao userDao = sqlSession.getMapper(UserDao.class);
            User user = userDao.selectUserById(uid);
            user.setUname("testUpdate1");
            user.setUpw("testUpdate1");
            int flag = userDao.update(user);
            sqlSession.commit();
            if(flag>0){
                System.out.println("更新数据成功！");
            }else{
                System.out.println("更新数据失败！");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public static void testSelectUserById(int uid){
            SqlSession sqlSession = null;
            try {
                sqlSession = MyBatisUtils.getSqlSesion("mybatis/mybatis.xml");
                UserDao userDao = sqlSession.getMapper(UserDao.class);
                User user = userDao.selectUserById(uid);
                System.out.println(user);
            } catch (IOException e) {
                e.printStackTrace();
            }
            
    }
    
    public static void testSelectAllUsers(){
        try {
            SqlSession sqlSession = MyBatisUtils.getSqlSesion("mybatis/mybatis.xml");
            UserDao userDao = sqlSession.getMapper(UserDao.class);
            List<User> userList = userDao.selectAllUsers();
            for(User user:userList){
                System.out.println(user);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static void testSelectAllUsersByPage(int index,int pageSize){
        try {
            SqlSession sqlSession = MyBatisUtils.getSqlSesion("mybatis/mybatis.xml");
            UserDao userDao = sqlSession.getMapper(UserDao.class);
            List<User> userList = userDao.selectAllUsersByPage((index-1)*pageSize, pageSize);
            for(User user:userList){
                System.out.println(user);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static void main(String[] args) {
        /*testSelectAllUsers(); //ok...*/    
        /*testInsertUser(); //ok...*/    
        /*testdeleteUserById(); //ok...*/
        /*testUpdateUserById(4);ok...*/
        /*testSelectUserById(2);ok...*/
        testSelectAllUsersByPage(2,2);
    }
}