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MyBatis limit分页设置的实现

错误的写法:

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< select id = "queryMyApplicationRecord" parameterType = "MyApplicationRequest" resultMap = "myApplicationMap" >

  SELECT

  a.*,

  FROM

  tb_user a

  WHERE 1=1

  < if test = "ids != null and ids.size()!=0" >

   AND a.id IN

   < foreach collection = "ids" item = "id" index = "index"

      open = "(" close = ")" separator = "," >

    #{id}

   </ foreach >

  </ if >

  < if test = "statusList != null and statusList.size()!=0" >

   AND a.status IN

   < foreach collection = "statusList" item = "status" index = "index"

      open = "(" close = ")" separator = "," >

    #{status}

   </ foreach >

  </ if >

  ORDER BY a.create_time desc

  LIMIT (#{pageNo}-1)*#{pageSize},#{pageSize}; // 错误

</ select >

 在MyBatis中LIMIT之后的语句不允许的变量不允许进行算数运算,会报错。

 正确的写法一:

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< select id = "queryMyApplicationRecord" parameterType = "MyApplicationRequest" resultMap = "myApplicationMap" >

  SELECT

  a.*,

  FROM

  tb_user a

  WHERE 1=1

  < if test = "ids != null and ids.size()!=0" >

   AND a.id IN

   < foreach collection = "ids" item = "id" index = "index"

      open = "(" close = ")" separator = "," >

    #{id}

   </ foreach >

  </ if >

  < if test = "statusList != null and statusList.size()!=0" >

   AND a.status IN

   < foreach collection = "statusList" item = "status" index = "index"

      open = "(" close = ")" separator = "," >

    #{status}

   </ foreach >

  </ if >

  ORDER BY a.create_time desc

  LIMIT ${(pageNo-1)*pageSize},${pageSize}; (正确)

</ select >

 正确的写法二:(推荐)

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< select id = "queryMyApplicationRecord" parameterType = "MyApplicationRequest" resultMap = "myApplicationMap" >

  SELECT

  a.*,

  FROM

  tb_user a

  WHERE 1=1

  < if test = "ids != null and ids.size()!=0" >

   AND a.id IN

   < foreach collection = "ids" item = "id" index = "index"

      open = "(" close = ")" separator = "," >

    #{id}

   </ foreach >

  </ if >

  < if test = "statusList != null and statusList.size()!=0" >

   AND a.status IN

   < foreach collection = "statusList" item = "status" index = "index"

      open = "(" close = ")" separator = "," >

    #{status}

   </ foreach >

  </ if >

  ORDER BY a.create_time desc

  LIMIT #{offSet},#{limit}; (推荐,代码层可控)

</ select >

 分析:方法二的写法,需要再请求参数中额外设置两个get函数,如下:

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@Data

public class QueryParameterVO {

 

  private List<String> ids;

 

  private List<Integer> statusList;

 

  // 前端传入的页码

  private int pageNo; // 从1开始

 

  // 每页的条数

  private int pageSize;

 

  // 数据库的偏移

  private int offSet;

 

  // 数据库的大小限制

  private int limit;

 

  // 这里重写offSet和limit的get方法

  public int getOffSet() {

   return (pageNo- 1 )*pageSize;

  }

 

  public int getLimit() {

   return pageSize;

  }

}

到此这篇关于MyBatis limit分页设置的实现的文章就介绍到这了,更多相关MyBatis limit分页内容请搜索以前的文章或继续浏览下面的相关文章希望大家以后多多支持!

原文链接:https://blog.csdn.net/timchen525/article/details/79647666

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