list

public void test11(){
        List<String> dbStr = new ArrayList<>();
        dbStr.add("aaa");
//        dbStr.add("cccc");
        dbStr.add("dddd");

        List<String> dbStr1 = new ArrayList<>();

        dbStr.add("aaa");
        dbStr.add("dddd");
        dbStr.add("ffff");

        for (String srt:dbStr) {
            if(!dbStr1.contains(srt)){
                dbStr.remove(srt);
            }
        }
        for (String ss:dbStr1) {
            if(id!=null){
                service.update(id);
            }else{
                service.add(id);
            }
        }

    }

CostTypes fatherType=new CostTypes();
            fatherType.setId(costSubTypeVO.getSid());
            fatherType.setTypeName(costSubTypeVO.getStypeName());
            costTypeService.updateById(fatherType);

            CostTypes fatherIdType=new CostTypes();
            fatherIdType.setFatherId(costSubTypeVO.getSid());
            List<CostTypes> oldSubTypeList=costTypeService.selectList(new EntityWrapper<>(fatherIdType));

            List<String> newSubTypeNames=new ArrayList<>();
            for (CostTypes newSubType: costSubTypeVO.getSubTypes()) {
                newSubTypeNames.add(newSubType.getTypeName());
            }

            for (CostTypes costType : costSubTypeVO.getSubTypes()) {
                if (costType.getId()!=null){

                    for (CostTypes oldSubType: oldSubTypeList) {
                        if (newSubTypeNames.contains(oldSubType.getTypeName())){

                        }
                    }

                    costTypeService.updateById(costType);
                }
                else {
                    CostTypes newType=new CostTypes();
                    newType.setTypeName(costType.getTypeName());
                    newType.setFatherId(costSubTypeVO.getSid());
                    costTypeService.insert(newType);
                }
            }

/**
             * 修改一级
             */
            CostTypes fatherType = new CostTypes();
            fatherType.setId(costSubTypeVO.getSid());
            fatherType.setTypeName(costSubTypeVO.getStypeName());
            costTypeService.updateById(fatherType);
            /**
             * 获取数据库中一级下的二级list
             */
            CostTypes fatherIdType = new CostTypes();
            fatherIdType.setFatherId(costSubTypeVO.getSid());
            List<CostTypes> dbList = costTypeService.selectList(new EntityWrapper<>(fatherIdType));
            /**
             * 将前端传过来的二级list的name单独取出
             */
            List<String> newStrList = new ArrayList<>();
            for (CostTypes newTypes : costSubTypeVO.getSubTypes()) {
                newStrList.add(newTypes.getTypeName());
            }
            /**
             * 先处理数据库的list 若数据库里的对象name不存在于新的list中，删除
             */
            for (CostTypes dbTypes : dbList) {
                if (!newStrList.contains(dbTypes.getTypeName())) {
                    costTypeService.deleteById(dbTypes.getId());
                }
            }
            /**
             * 再处理前端的 若id不为空 则修改
             * id为空 则新增
             */
            for (CostTypes newList : costSubTypeVO.getSubTypes()) {
                if (newList.getId() != null) {
                    costTypeService.updateById(newList);
                } else {
                    CostTypes newType = new CostTypes();
                    newType.setTypeName(newList.getTypeName());
                    newType.setFatherId(costSubTypeVO.getSid());
                    costTypeService.insert(newType);
                }
            }