Java将字符串日期转换为秒

Question

I have some inputs:

1h50m22s
2h40m10s
33m03s

And I have to convert to seconds in java.

Already extract numbers with regex '\\d+|\\D+'.

Answer 1

Joda-Time

Don't reinvent the wheel. The Joda-Time library can parse those values for you. No need for regex.

ISO 8601

Those values are close to being in standard ISO 8601 format. Specifically the Durations format, PnYnMnDTnHnMnS . The P marks the beginning, the T separates the date portion from the time position. If you have time-only values, then simply prepend the PT to get PT33m03s . Lastly convert to uppercase to get PT33M03S .

Joda-Time both parses and generates such strings by default. Once your input is in standard format, you can pass it directly to Joda-Time. Skip the regex.

Alternatively, you can specify a PeriodFormatter to fit your exact input strings. Then you can parse the original input strings without converting to standard format.

If you have any control or influence over the source of your input strings, I strongly suggest altering that source to utilize the ISO 8601 format.

Period Class

Next, use the Period class to automatically parse that value into a Period object. A Period represents a span of time as a number of months, days, hours, and such. Not tied to points on the timeline of the history of the Universe. (If you have specific points on a timeline, use the Interval class.)

Duration Class

Next, call toStandardDuration to get a Duration object. A Duration in Joda-Time represents a span of time as just the passage of time. Merely a number of milliseconds, not a specific number of months or hours or such chunks.

Lastly, on that Duration object call getStandardSeconds to get your answer.

Much easier than dealing with regex. And more reliable as Joda-Time is already built, debugged, well-worn, and able to handle the various permutations of possible input strings.

Example Code

Using Joda-Time 2.5.

Succinct version (not recommended).

String input = ( "PT" + "33m03s" ).toUpperCase();
long durationInSeconds = Period.parse( input ).toStandardDuration().getStandardSeconds();

Detailed version.

// Convert input string to standard ISO 8601 format.
// Alternatively, you could use a formatter to parse your original string rather than convert.
String inputRaw = "33m03s";
String inputStandard = "PT" + inputRaw; // Assuming this is a time-only without date portion, prepend 'PT' to make standard ISO 8601 format.
inputStandard = inputStandard.toUpperCase();

// Parse string as Period object.
Period period = Period.parse( inputStandard );

// Convert from Period to Duration to extract total seconds.
Duration duration = period.toStandardDuration();
long durationInSeconds = duration.getStandardSeconds();  // Returns getMillis() / 1000. The result is an integer division, so 2999 millis returns 2 seconds.

Dump to console.

System.out.println( "inputRaw : " + inputRaw );
System.out.println( "inputStandard : " + inputStandard );
System.out.println( "period : " + period );  // Notice how the leading zero on the 'seconds' number is gone. We have a Period *object*, not messing with strings.
System.out.println( "duration : " + duration );
System.out.println( "durationInSeconds : " + durationInSeconds );

When run.

inputRaw : 33m03s
inputStandard : PT33M03S
period : PT33M3S
duration : PT1983S
durationInSeconds : 1983

Answer 2

You can easily do it using Joda-Time .

Using Pattern class first in order to extract fields:

Pattern pattern = Pattern.compile("(?:(\\d+)h)?(?:(\\d+)m)?(?:(\\d+)s)?");
Matcher matcher = pattern.matcher("1h50m22s");
matcher.matches();
String hours = matcher.group(1);
String minutes = matcher.group(2);
String seconds = matcher.group(3);

Period period = new Period();
if(hours != null){
    period = period.withHours(Integer.parseInt(hours));
}
if(minutes != null){
    period = period.withMinutes(Integer.parseInt(minutes));
}
if(seconds != null){
    period = period.withSeconds(Integer.parseInt(seconds));
}
int totalSeconds = period.toStandardSeconds().getSeconds();

Using PeriodFormatterBuilder class (less flexible for parsing patterns):

String dateText = "1h50m22s";
PeriodFormatterBuilder formatterBuilder = new PeriodFormatterBuilder();

if(dateText.contains("h")){
    formatterBuilder.appendHours().appendLiteral("h");
}
if(dateText.contains("m")){
    formatterBuilder.appendMinutes().appendLiteral("m");
}
if(dateText.contains("s")){
    formatterBuilder.appendSeconds().appendLiteral("s");
}

Period period = formatterBuilder.toFormatter().parsePeriod(dateText);
int totalSeconds = period.toStandardSeconds().getSeconds();

Answer 3

You might want to use String's substring method to extract the number you want and parse it to an integer. For example just to get seconds you can do:

String time = "32h45m93s";
String seconds = time.substring(time.indexOf('m') + 1, time.indexOf('s'));
int seconds = Integer.parseInt(seconds);

I didn't run it, but this is the general idea. Do the same with hours and minutes and then

int totalSeconds = hours * 3600 + minutes * 60 + seconds;