作用：减少数据处理量

数据库分页语法：

SELECT * from table limit startIndex,pageSize

 
Mybatis层面实现分页：

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

<select id="getUserByLimit" parameterType="map" resultType="com.Nana.pojo.User">select * from mybatis.user limit #{startIndex},#{pageSize}
</select>

public void  getUserByLimit(){SqlSession sqlSession = MybatisUtils.getSqlSession();Map<String,Integer> map = new HashMap<String, Integer>();map.put("startIndex",0);map.put("pageSize",2);UserMapper mapper = sqlSession.getMapper(UserMapper.class);List<User> user = mapper.getUserByLimit(map);for (User user1 : user) {System.out.println(user1);}sqlSession.close();
}

 
Java代码层面实现分页：

List<User> getUserByRowBounds();

<select id="getUserByRowBounds" parameterType="map" resultType="com.Nana.pojo.User">select * from mybatis.user
</select>

public void  getUserByRowBounds(){SqlSession sqlSession = MybatisUtils.getSqlSession();RowBounds rowBounds = new RowBounds(1, 2);List<User> user = sqlSession.selectList("com.Nana.dao.UserMapper.getUserByRowBounds", null, rowBounds);for (User user1 : user) {System.out.println(user1);}sqlSession.close();
}

 
分页插件实现分页：

https://pagehelper.github.io/docs/howtouse/