java中controller，service，serviceImpl，mapper，xml等几个文件的作用理解，以简单的查询为例

一、controller、service、serviceImpl、Mapper、Xml等文件的作用
下图为java约定俗成的几个文件的作用

二、在项目中的使用情况，由于业务逻辑很简单，所以每个文件中的代码行数都很少

• controller.java

    /**
     * 资产rim项目信息报表
     *
     */
    @RequestMapping(value = "/hls/cus/rpt/rim/project/detail/query")
    @ResponseBody
    public ResponseData rptRimProjecrDetailQuery(@RequestBody Map map) {
        return new ResponseData(hlsCusRptRimProjectDetailService.rptRimProjectDetailQuery(map));
    }

• service.java

public interface HlsCusRptRimProjectDetailService extends IBaseService,ProxySelf {
 
    List

• serviceImpl.java

    @Override
    public List

• mapper.java

public interface HlsCusRptRimProjectDetailMapper extends Mapper {
 
    List

• mapper.xml

 
        SELECT
         V.*,
        (case when V.REMAIN_PRINCIPAL > 0 then (V.REMAIN_PRINCIPAL - nvl(
        (SELECT SUM(CCC.DUE_AMOUNT)
        FROM CON_CONTRACT_CASHFLOW CCC
        WHERE CCC.CONTRACT_ID = V.CONTRACT_ID
        AND CCC.CF_ITEM = 5)
        ,0)) else 0 end) as PROJECT_EXPOSURE
        FROM (SELECT
        --项目编号
        CC.PROJECT_CONTRACT_NUMBER PROJECT_NUMBER,
 
        -------------------------省略部分代码-------------------------
        
        -- 项目核销申请日期
        (SELECT CCT.TERMINATION_DATE
        FROM CON_CONTRACT_TERMINATION CCT
        WHERE CCT.CONTRACT_ID = CC.CONTRACT_ID) TERMINATION_DATE,
        CC.BEFORE_RENT_FLAG
        FROM CON_CONTRACT CC
        LEFT JOIN PRJ_PROJECT PP
        ON CC.PROJECT_ID = PP.PROJECT_ID
        WHERE
        cc.contract_status IN ('INCEPT', 'TERMINATE', 'ET')
        OR (CC.contract_status = 'SIGN' AND cc.before_rent_flag = 'Y')
      ) V
        ----------------下面写查询条件----------------------
        
            
                and v.project_number like concat(concat('%',#{projectNumber}),'%')
            
            
              and v.business_type in
              
                #{item}
              
            
        
 
    

原文：https://blog.csdn.net/congweijing/article/details/82499627