为什么这个 SimpleDateFormat 不能解析这个日期字符串？

Question

The SimpleDateFormat:

SimpleDateFormat pdf = new SimpleDateFormat("MM dd yyyy hh:mm:ss:SSSaa");

The exception thrown by pdf.parse("Mar 30 2010 5:27:40:140PM"); :

java.text.ParseException: Unparseable date: "Mar 30 2010 5:27:40:140PM"

Any ideas?

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Edit: thanks for the fast answers. You were all correct, I just missed that one key sentence in the SimpleDateFormat docs - I should probably call it a day.

Answer 1

First, three-char months are to be represented by MMM . Second, one-two digit hours are to be represented by h . Third, Mar seems to be English, you'll need to supply a Locale.ENGLISH , else it won't work properly in machines with a different default locale.

The following works:

SimpleDateFormat sdf = new SimpleDateFormat("MMM dd yyyy h:mm:ss:SSSa", Locale.ENGLISH);
System.out.println(sdf.parse("Mar 30 2010 5:27:40:140PM"));

Result (I'm at GMT-4 w/o DST):

Tue Mar 30 17:27:40 BOT 2010

Also see the java.text.SimpleDateFormat javadoc .

Why you called it pdf is beyond me, so I renamed it sdf ;)

Answer 2

From SimpleDateFormat javadocs :

Month: If the number of pattern letters is 3 or more, the month is interpreted as text; otherwise, it is interpreted as a number.

Try to use pattern like "MMM dd yyyy"

Answer 3

MM stands for numeric month. Use MMM.

Answer 4

java.time

I am providing the modern answer. The other answers are correct, but the SimpleDateFormat class that you used is notoriously troublesome and long outdated. Instead I am using java.time, the modern and superior Java date and time API.

    DateTimeFormatter formatter = DateTimeFormatter.ofPattern(
            "MMM d uuuu h:mm:ss:SSSa", Locale.ROOT);
    String dateTimeString = "Mar 30 2010 5:27:40:140PM";
    LocalDateTime dateTime = LocalDateTime.parse(dateTimeString, formatter);
    System.out.println(dateTime);

Output:

2010-03-30T17:27:40.140

Link: Oracle tutorial: Date Time explaining how to use java.time.