如何将 Json 日期转换为 Java 日期

Question

I am trying to convert Json date string to java date format. However, it gives error when it comes to "return df.parse( tarih )" line.

JSON :

{"DateFrom":"\/Date(1323087840000+0200)\/"}

Java code :

private Date JSONTarihConvert(String tarih) throws ParseException
{


    SimpleDateFormat df = new SimpleDateFormat( "yyyy-MM-dd'T'HH:mm:ssz" );


    if ( tarih.endsWith( "Z" ) ) {
        tarih = tarih.substring( 0, tarih.length() - 1) + "GMT-00:00";
    } else {
        int inset = 6;


        String s0 = tarih.substring( 6, tarih.length()-1 - inset );
        String s1 = tarih.substring( tarih.length()- inset,tarih.length()-2 );

        tarih = s0 + "GMT" + s1;
    }


        return df.parse( tarih );

}

When I call this method, tarih parameter is: /Date(1323087840000+0200)/

Answer 1

As you're interested in a Date object and the JSON occurs to me to be a unix timestamp.
Therefore I'd recommend you the Date(long milliseconds) constructor :)

private Date JSONTarihConvert(String tarih) throws ParseException{
    long timestamp = getTimeStampFromTarih(tarih);
    return new Date(timestamp);
}

Where getTimeStampFromTarih extracts the milliseconds before the occurrence of "+"

Answer 2

This will work surely

String date = "/Date(1376841597000)/";
Calendar calendar = Calendar.getInstance();
String datereip = date.replace("/Date(", "").replace(")/", "");
Long timeInMillis = Long.valueOf(datereip);
calendar.setTimeInMillis(timeInMillis);
System.out.println(calendar.getTime().toString("dd-MMM-yyyy h:mm tt"));//It Will Be in format 29-OCT-2014 2:26 PM

Answer 3

First replace string like this :

String str= ConvertMilliSecondsToFormattedDate(strDate.replace("/Date(","").replace(")/", ""));

Then Convert it like this:

public static String ConvertMilliSecondsToFormattedDate(String milliSeconds){
    Calendar calendar = Calendar.getInstance();
    calendar.setTimeInMillis(Long.parseLong(milliSeconds));
    return simpleDateFormat.format(calendar.getTime());
}

Answer 4

You will Need to type cast date:

String rawdate = "/Date(1995769286000)/";
Calendar calendarins = Calendar.getInstance();
String datereip = rawdate.replace("/Date(", "").replace(")/", "");
Long timeInMillis = Long.valueOf(datereip);
calendar.setTimeInMillis(timeInMillis);
System.out.println(calendar.getTime().toString("dd-MMM-yyyy h:mm tt"));

Answer 5

Unless you have a reason not to, you should be using a parser to serialize and de-serialize objects. Like Jackson parser.

Answer 6

java.time

This is the modern answer (since 2014).

First I want to make sure the timestamp I have really lives up to the format I expect. I want to make sure if one day it doesn't, I don't just pretend and the user will get incorrect results without knowing they are incorrect. So for parsing the timestamp string, since I didn't find a date-time format that would accept milliseconds since the epoch, I used a regular expression:

    String time = "/Date(1479974400000-0800)/";
    Pattern pat = Pattern.compile("/Date\\((\\d+)([+-]\\d{4})\\)/");
    Matcher m = pat.matcher(time);
    if (m.matches()) {
        Instant i = Instant.ofEpochMilli(Long.parseLong(m.group(1)));
        System.out.println(i);
    }

This prints:

2016-11-24T08:00:00Z

It is not clear to me whether you need to use the zone offset and for what purpose. But since we've got it, why not retrieve it from the matcher and use it for forming an OffsetDateTime , a date and time with UTC offset. Here's how:

        ZoneOffset zo = ZoneOffset.of(m.group(2));
        OffsetDateTime odt = OffsetDateTime.ofInstant(i, zo);
        System.out.println(odt);

2011-12-05T14:24+02:00

If you need an old-fashioned java.util.Date for some legacy API:

        System.out.println(Date.from(i));

Or if using the backport mentioned in the links below:

        System.out.println(DateTimeUtils.toDate(i));

On my computer it prints

Mon Dec 05 13:24:00 CET 2011

The exact output will depend on your time zone.

Links

• Oracle tutorial: Date Time explaining how to use java.time.
• Java Specification Request (JSR) 310 , where java.time was first described.
• ThreeTen Backport project , the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
• ThreeTenABP , Android edition of ThreeTen Backport
• Question: How to use ThreeTenABP in Android Project , with a very thorough explanation.