利用java反射解决Mybatis Pagehelper插件联表查询分页不准确的问题（二）-阿里云开发者社区

利用java反射解决Mybatis Pagehelper插件联表查询分页不准确的问题（二）

2021-11-10 321

版权

本文内容由阿里云实名注册用户自发贡献，版权归原作者所有，阿里云开发者社区不拥有其著作权，亦不承担相应法律责任。具体规则请查看《阿里云开发者社区用户服务协议》和《阿里云开发者社区知识产权保护指引》。如果您发现本社区中有涉嫌抄袭的内容，填写侵权投诉表单进行举报，一经查实，本社区将立刻删除涉嫌侵权内容。

简介： 利用java反射解决Mybatis Pagehelper插件联表查询分页不准确的问题

CompanyWhere 源码：

package com.easy.xdo;
import lombok.Data;
@Data
public class CompanyWhere extends CompanyDO{
  /**
     * page -1 默认不分页
     */
    private int page;
    private int rows;
    private int startrow;
    private String suffix;
}

CompanyParam 源码：

package com.easy.xdo;
import lombok.Data;
@Data
public class CompanyParam {
  private CompanyDO xdo;
  private CompanyWhere where;
}

EmployeDO源码：

package com.easy.xdo;
import lombok.Data;
@Data
public class EmployeDO {
    //演示员工类
  private String id;
  private String name;
  private String age;
  private String companyid;
}

CompanyController源码：

package com.easy.controller;
import io.swagger.annotations.Api;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.easy.service.CompanyService;
import com.easy.util.PageUtil;
import com.easy.xbo.PageBO;
import com.easy.xdo.CompanyParam;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import io.swagger.annotations.ApiOperation;
@Api("API-公司接口")
@RestController
@RequestMapping("api/v1/company")
public class CompanyController {
  @Autowired
    private CompanyService companyService;
  @ApiOperation(value = "分页查询")
    @PostMapping("/page")
    public PageBO page() throws Exception{
    CompanyParam param=new CompanyParam();
        return PageUtil.getPageBOData(companyService,param);
    }
}

CompanyService 源码：

package com.easy.service;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import com.easy.dao.CompanyDAO;
import com.easy.xdo.CompanyDO;
import com.easy.xdo.CompanyParam;
public class CompanyService {
  @Autowired
  private CompanyDAO companyDAO;
  public List<CompanyDO> selectPage(CompanyParam param){
        return companyDAO.selectList(param);
    }
    public int selectCount(CompanyParam param){
        return companyDAO.selectCount(param);
    }
}

xml源码

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.easy.dao.CompanyDAO">
  <resultMap id="BaseResultMap" type="com.easy.xdo.CompanyDO">
    <id column="id" property="id" />
    <result column="name" property="name" />
    <result column="address" property="address" />
    <collection property="employes" ofType="com.easy.xdo.EmployeDO">
      <id column="eid" property="id" />
      <result column="ename" property="name"/>
      <result column="age" property="age"/>
    </collection>
  </resultMap>
  <sql id="sqlBase">
     c.id,c.name,c.address,e.id as eid,e.name as ename,e.age 
  </sql>
  <sql id="WhereModelSql">
    <if test="where != null">
      <where>
        <if test="where.id != null and where.id != ''"> AND c.id=#{where.id} </if>
        <if test="where.name != null and where.name != ''"> AND c.name=#{where.name} </if>
        <if test="where.address != null and where.address != ''"> AND c.address=#{where.address} </if>
      </where>
    </if>
  </sql>
  <select id="selectList" resultMap="BaseResultMap" parameterType="com.easy.xdo.CompanyParam">
    select
    <include refid="sqlBase" />
    from company c left join employe e on  c.id=e.companyid  
    where c.id in (select page.id from (select id from company 
    <include refid="WhereModelSql" />  limit #{where.startrow},#{where.rows})
    page)
  </select>
  <select id="selectCount" resultType="java.lang.Integer" parameterType="com.easy.xdo.CompanyParam">
    select
    count(c.id)
    from company
    <include refid="WhereModelSql" />
  </select>
</mapper>