Description: Take out the non-DataTime in cp. Is the following code reasonable? Is there any concurrency problem with deviceDataMap?

Map<String,Map<String,String>> deviceDataMap = new HashMap<>();
String cp = "DataTime=20040506010101;SB1-RT=1.1;SB2-RT=2.1";

List<String> cpValusList = Arrays.asList(cp.split(";"));

    cpValusList.stream().filter(item -> !item.contains("DataTime=")).forEach(item ->{
        String deviceId = item.substring(0,item.indexOf("-"));
        if(!deviceDataMap.containsKey(deviceId)){
            Map<String,String> oneDeviceIdValusMap = new HashMap<>();
            List<String> deviceIdValueList = Arrays.asList(item.split(","));
            deviceIdValueList.forEach(value->{
                String[] temp = value.split("=");
                oneDeviceIdValusMap.put(temp[0], temp[1]);
            });
            
            deviceDataMap.put(deviceId, oneDeviceIdValusMap);
        }
        
    });