Java-多表聯查

前提：由於我當前頁面顯示的數據 是在其他兩個表中 只有ID可以使用

 

   1、分別對兩個表進行操作，將List轉為Map對象

//查詢項目表
List<BudgetProjectInfo> budgetProjectInfoList = budgetProjectInfoService.list();
Map<String,BudgetProjectInfo> schemMap = budgetProjectInfoList.stream().collect(Collectors.toMap(BudgetProjectInfo::getId,Function.identity()));
//查詢部門表
List<ComDept> comDeptList = comDeptServiceImpl.list();
Map<String,ComDept> deptMap = comDeptList.stream().collect(Collectors.toMap(ComDept::getId, Function.identity()));

2、設置頁面所需要的數據，篩選條件

QueryWrapper<BudgetSchemeInfo> schemeQuery = Wrappers.query();
schemeQuery.eq(StringUtils.isNotEmpty(schemeInfo.getDeclareYear()), BudgetSchemeInfoUtil.COLUMN_DECLARE_YEAR,schemeInfo.getDeclareYear())
      .eq(StringUtils.isNotEmpty(schemeInfo.getDepId()),BudgetSchemeInfoUtil.COLUMN_DEP_ID,schemeInfo.getDepId())
      .eq(StringUtils.isNotEmpty(schemeInfo.getDataSource()),BudgetSchemeInfoUtil.COLUMN_DATA_SOURCE,schemeInfo.getDataSource())
      .eq(StringUtils.isNotEmpty(schemeInfo.getSchoolCode()),BudgetSchemeInfoUtil.COLUMN_SCHOOL_CODE,schemeInfo.getSchoolCode());
Page<BudgetSchemeInfo> page = new Page<>(schemeInfo.getPageCurrent(), schemeInfo.getPageSize());
IPage<BudgetSchemeInfo> budgetSchemeInfoIPage = this.page(page, schemeQuery);

3、寫VO，例如（里面寫的是自己數據庫沒有，要調用其他數據庫的數據的值，記得導入Get和Set，此處略）

/** 項目編號**/
private String proCode;
/** 項目名稱**/
private String proName;
/** 部門編號**/
private String deptNum;
/** 部門名稱**/
private String deptName;
/** 項目狀態**/
private String proStatus;

4、將實體對象轉換為VO

List<BudgetSchemeVO> fmsAtInfoVOList = ObjectParamCopyUtil.copyList(budgetSchemeInfoIPage.getRecords(),BudgetSchemeVO.class);

5、循環獲取數據（根據ProId找項目表中數據，根據DepId找部門表中數據）

for (BudgetSchemeVO b:fmsAtInfoVOList){
   b.setProCode(schemMap.get(b.getProId()).getProNo());
   b.setProName(schemMap.get(b.getProId()).getProName());
   if(StringUtils.isNotEmpty(deptMap.get(b.getDepId()).getDeptNum())) {
      b.setDeptNum(deptMap.get(b.getDepId()).getDeptNum());
   }
   //b.setDeptNum(deptMap.get(b.getDepId()).getDeptNum());
   b.setDeptName(deptMap.get(b.getDepId()).getDeptName());
   b.setProStatus(schemMap.get(b.getProId()).getStatus());

}

6、返回數據

return ResultJsonUtil.returnResult(ResultEnum.SUCCESS, VoUtilFactory.convertToVoPage(fmsAtInfoVOList,budgetSchemeInfoIPage));