采用递归的形式做Java树状形式解析

private List<GpsStrategyVO> recursionGetGpsStrategy(List<GpsStrategy> gpsStrategies,int parentId){
       List<GpsStrategyVO> next = new ArrayList<>();
       //1.获取所有子集合
       gpsStrategies.stream().forEach(gpsStrategyVO ->{
           if(parentId == gpsStrategyVO.getParentId()){
               GpsStrategyVO strategyVO = new GpsStrategyVO();
               BeanUtils.copyProperties(gpsStrategyVO,strategyVO);
               next.add(strategyVO);
           }
       });

       //2.遍历子集合，给当前每一条数据插入子集合（递归）
       if (!ObjectIsNullUtil.isNullOrEmpty(next)){
           next.stream().forEach(gpsStrategyVO -> {
               List<GpsStrategyVO> gpsStrategyVOS = recursionGetGpsStrategy(gpsStrategies, gpsStrategyVO.getStrategyId());
               if (!ObjectIsNullUtil.isNullOrEmpty(gpsStrategyVOS)){
                   gpsStrategyVO.setNext(gpsStrategyVOS);
               }
               //2.1 获取策略详情列表
               if (null == gpsStrategyDetailVOList){
                   getGpsStrategyDetailVOs();
               }
               //2.2 获取当前策略id对应的策略详情
               gpsStrategyVO.setGpsStrategyDetails(gpsStrategyDetailService.selectStrategyDetailsByStrategyIdLogic(gpsStrategyDetailVOList,gpsStrategyVO.getStrategyId()));
           });
       }
       return next;
   }
   
   private static List<GpsStrategyDetailVO> gpsStrategyDetailVOList = null;
   
    /**
    * 初始化策略详情
    * @return
    */
   public List<GpsStrategyDetailVO> getGpsStrategyDetailVOs(){
       if(gpsStrategyDetailVOList == null){
           gpsStrategyDetailVOList = gpsStrategyDetailService.selectAll();
       }
       return gpsStrategyDetailVOList;
   }

场景

• 该场景是做一个树状结构的返回。其中，最高级别的parentId设置为0.则调用方法只需传入整个列表和0即可：

  //1.查询全部
  List<GpsStrategy> gpsStrategies = gpsStrategyService.selectAll();
  //2.递归
  List<GpsStrategyVO> strategies = recursionGetGpsStrategy(gpsStrategies, 0);

递归解释

• 先获取当前条件下所有子查询