1、分页

思考：为什么要分页？

• 缩小数据的处理量

应用Limit分页

#语法：SELECT * FROM `user` LIMIT startIndex,pageSize;# [0,3]SELECT * FROM `user` LIMIT 3;

应用Mybatis实现分页，外围SQL
1.接口

//分页List<User> getUserByLimit(Map<String,Integer> map);

2.Mapper.xml

<resultMap id="UserMap" type="User">    <!--column数据库中的字段，property实体类中的属性-->    <result column="id" property="id"/>    <result column="name" property="name"/>    <result column="pwd" property="password"/></resultMap><select id="getUserByLimit" parameterType="map" resultMap="UserMap">    select * from mybatis.user limit #{startIndex},#{pageSize}</select>

3.测试

@Testpublic void getUserByLimit(){    SqlSession sqlSession = MybatisUtils.getSqlSession();    UserMapper mapper = sqlSession.getMapper(UserDao.class);    Map<String,Integer> map = new HashMap<>();    map.put("startIndex",0);    map.put("pageSize",2);    List<User> userList = mapper.getUserByLimit(map);    for(User user:userList){        System.out.println(user);    }    //敞开    sqlSession.close();    }