MyBatis limit分页设置

错误的写法：

<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：
<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）
<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：
@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;
    }
}

错误的写法：
<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：<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）<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：@Datapublic 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;    }}
--------------------- 作者：timchen525 来源：CSDN 原文：https://blog.csdn.net/timchen525/article/details/79647666 版权声明：本文为博主原创文章，转载请附上博文链接！