java8多个字段分组实战

List printValueVOListAllDeal = new ArrayList<>();                
Map> groupMap = printValueVOListAll.stream().collect(Collectors.groupingBy(a -> a.getSupplierCommodityId() + "," + a.getLotNumber() + "," + a.getExpiryDate() + "," + a.getPrice()));
                for(Map.Entry> entry : groupMap.entrySet()){
                    PrintValueVO printValueVO = new PrintValueVO();
                    BeanUtils.copyProperties(entry.getValue().get(0), printValueVO);

                    BigDecimal basevalue = BigDecimal.ZERO;
                    BigDecimal inputValue = BigDecimal.ZERO;
                    BigDecimal amount = BigDecimal.ZERO;
                    for(PrintValueVO subDTO: entry.getValue()){
                        basevalue = basevalue.add(subDTO.getbaseNumber() != null ? subDTO.getbaseNumber(): BigDecimal.ZERO);
                        inputValue = inputValue.add(subDTO.getInputNumber() != null ? subDTO.getInputNumber(): BigDecimal.ZERO);
                        amount = amount.add(subDTO.getEachPrice() != null ? subDTO.getEachPrice(): BigDecimal.ZERO);
                    }
                    printValueVO.setbaseNumber(basevalue);
                    printValueVO.setInputNumber(inputValue);
                    printValueVO.setEachPrice(amount);
                    printValueVO.setAmount(amount);
                    printValueVOListAllDeal.add(printValueVO);
                }