如何将双精度值格式化为时间 [英] How to format a double value as time

问题描述

我正在研究一个读取gps数据的程序. NMEA字符串返回的时间如下:34658.00.

I am working on a program that reads gps data. A NMEA string returns time like this: 34658.00.

我的解析器将其视为双精度

My parser treats that as a double

InputLine = "\\$GPGGA,34658.00,5106.9792434234,N,11402.3003,W,2,09,1.0,1048.47,M,-16.27,M,08,AAAA*60";
    //NMEA string
    //inputLine=input.readLine();
    if(inputLine.contains("$GPGGA")) {
        String gpsgga = inputLine.replace("\\", "");
        String[] gga = gpsgga.split(",");

        String utc_time = gga[1];



        if (!gga[1].isEmpty()) {
            Double satTime = Double.parseDouble(utc_time);
            gpsData.setgpsTime(satTime);
        }

我该如何将34658.00格式化为03:46:58?

How would I go about formatting 34658.00 as 03:46:58?

推荐答案

    DateTimeFormatter nmeaTimeFormatter = DateTimeFormatter.ofPattern("Hmmss.SS");
    String utcTime = "34658.00";
    System.out.println(LocalTime.parse(utcTime, nmeaTimeFormatter));

此打印

03:46:58

03:46:58

首先解析为double是绕道而行，它只会为您提供比必要的更为复杂的代码，因此请避免这种情况.就像解析任何其他格式的时间一样，只需解析时间即可.上面的内容也可以在上午10点后的时间工作，但小时数是两位数吗?是的输入:

Parsing into a double first is the detour, it just gives you more complicated code than necessary, so avoid that. Just parse the time as you would parse a time in any other format. Does the above also work for times after 10 AM where the hours are two digits? It does. Input:

    String utcTime = "123519.00";

输出:

12:35:19

12:35:19

尽管它确实需要两个小数(如果它们不为零，则将它们返回).如果小数位数可能有所不同，则至少有两个选项

It does require exactly two decimals, though (and will render them back if they are non-zero). If the number of decimals may vary, there are at least two options

1. 使用DateTimeFormatterBuilder指定小数部分(甚至是可选的小数部分)，其小数位数介于0到9之间.
2. hack:使用String.replaceFirst和正则表达式删除小数部分，然后再将其从格式模式字符串中删除.

1. Use a DateTimeFormatterBuilder to specify a fractional part (even an optional fractional part) with anything between 0 and 9 decimals.
2. The hack: use String.replaceFirst with a regular expression to remove the fractional part, and then also remove it from the format pattern string.

它还要求小数点前至少5位数字，因此一天中第一个小时的时间必须有前导零，例如00145.00表示00:01:45.

It also requires at least 5 digits before the decimal point, so times in the first hour of day need to have leading zeroes, for example 00145.00 for 00:01:45.

由于时间始终是UTC，因此您可能想使用atOffset将LocalTime转换为带有ZoneOffset.UTC的OffsetTime.如果您也知道日期，则OffsetDateTime或Instant是合适的，但是我对文档的了解不够深，无法确定您是否知道日期.

Since the time is always in UTC, you may want to use atOffset to convert the LocalTime into an OffsetTime with ZoneOffset.UTC. If you know the date too, an OffsetDateTime or an Instant would be appropriate, but I haven’t delved enough into the documentation to find out whether you know the date.

• Oracle教程:日期时间解释了如何使用java.time./li>
• NMEA数据

• Oracle tutorial: Date Time explaining how to use java.time.
• NMEA data

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