How to parse date string EEE MMM dd to yyyy-MM-dd in java [duplicate]

问题

I'm having the date in this pattern EEEEE MMMMM yyyy HH:mm:ss.SSSZ, I would like to convert this to yyyy-MM-dd format in java, I tried below approach but I'm getting this exception java.text.ParseException: Unparseable date:

   SimpleDateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy");
    String dateInString = "Sun Oct 01 00:00:00 EDT 2017";

    try {

        Date date = formatter.parse(dateInString);
        System.out.println(date);
        System.out.println(formatter.format(date));

    } catch (ParseException e) {
        e.printStackTrace();
    }

Can someone please help me to resolve this?

Thanks.

回答1:

From java-8 you can use the ZonedDateTime with pattern of your input date which is EEE MMM dd HH:mm:ss zzz yyyy

String dateInString = "Sun Oct 01 00:00:00 EDT 2017";

ZonedDateTime time = ZonedDateTime.parse(dateInString,DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss zzz yyyy"));
System.out.println(time.toLocalDate());   //2017-10-01

By default LocalDate is without a time-zone in the ISO-8601 calendar system, such as 2007-12-03.

回答2:

You've defined your formatter as the concept 'date, month, year', and then you try to ask it to parse a string that isn't in this format at all. You need to make a formatter that can format Sun Oct 01 00:00:00 EDT 2017, and dd-MMM-yyyy obviously isn't it. The javadoc of SimpleDateFormat will tell you what combination of letters you need to use.

Once you've got that, it's easy: parse with this new formatter, then call .format with your old one (the dd-MMM-yyyy one).

回答3:

You can't use the same formatter for both parsing and formatting. See this answer: https://stackoverflow.com/a/999191

回答4:

You double-create the DateFormat one parse and once to format

DateFormat dfParse = new SimpleDateFormat("EEEEE MMMMM yyyy HH:mm:ss.SSSZ");
DateFormat dfFormat = new SimpleDateFormat("yyyy-MM-dd");
dfFormat.format(dfParse.parse("Sun Oct 01 00:00:00 EDT 2017"))

来源：https://stackoverflow.com/questions/58313283/how-to-parse-date-string-eee-mmm-dd-to-yyyy-mm-dd-in-java

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java

date

java-8