Set<String> gatherTimeList = eSResponseList.stream() .map(DevPortReportEsDTO::getGatherTime) // 获取目标字段的值 .collect(Collectors.toSet()); // 转为列表 Map<String, DevPortReportEsDTO> reportEsDTOMap = new HashMap<>(); Map<String, List<PortReportResultVo>> relayLinkAndPortMap1 = new HashMap<>(); for (Map.Entry<String, List<TrDevportVO>> entry : relayLinkAndPortListMap.entrySet()) { String key = entry.getKey(); List<TrDevportVO> values = entry.getValue(); List<PortReportResultVo> resultVoList = new ArrayList<>(); for (String gatherTime : gatherTimeList) { for (TrDevportVO trDevportVO : values) { String tempKey = trDevportVO.getDevId() + trDevportVO.getPortName() + gatherTime; DevPortReportEsDTO reportEsDTO = reportEsDTOMap.get(tempKey); PortReportResultVo reportResultVo = new PortReportResultVo(); BeanUtil.copyProperties(trDevportVO, reportResultVo); reportResultVo.setPortBandwidth(trDevportVO.getBandwidth()); BeanUtil.copyProperties(reportEsDTO, reportResultVo); resultVoList.add(reportResultVo); } // key为链路组id+ 采集时间 relayLinkAndPortMap1.put(key + "@" + gatherTime, resultVoList); } } 优化一下这段代码

可以考虑将两个循环嵌套的部分使用 Stream 进行优化，减少循环次数，如下所示：

Map<String, List<PortReportResultVo>> relayLinkAndPortMap1 = relayLinkAndPortListMap.entrySet().stream()
        .flatMap(entry -> gatherTimeList.stream()
                .map(gatherTime -> {
                    String key = entry.getKey();
                    List<TrDevportVO> values = entry.getValue();
                    return values.stream()
                            .map(trDevportVO -> {
                                String tempKey = trDevportVO.getDevId() + trDevportVO.getPortName() + gatherTime;
                                DevPortReportEsDTO reportEsDTO = reportEsDTOMap.get(tempKey);
                                PortReportResultVo reportResultVo = new PortReportResultVo();
                                BeanUtil.copyProperties(trDevportVO, reportResultVo);
                                reportResultVo.setPortBandwidth(trDevportVO.getBandwidth());
                                BeanUtil.copyProperties(reportEsDTO, reportResultVo);
                                return reportResultVo;
                            })
                            .collect(Collectors.toList());
                })
                .map(resultVoList -> key + "@" + gatherTime, resultVoList))
        .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));

这样可以减少循环次数，提高代码效率。