解析非标准日期格式，例如“ + 0yyyyMMdd”

Question

I Have Date, that comes to our system in format +0yyyyMMdd

For instance 12 March,2011 is +020110312

For now it's definitely + symbol and one 0 before Date, but in future it may be more than one zeros ,eg +000020110312

Is it possible to parse it with standard Java java.text.DateFormat.parse(String source) ?

Or I should write custom parsing method?

Thank you.

Answer 1

I'd guess the +0 is a timezone indicator, so you can try:

new SimpleDateFormat("ZyyyyddMM")

Alas, this doesn't work immediately.

In order to make it work, get a substring from 0 to length - 8 and expand it to be four digits to meet the RFC for the timezone. See SimpleDateFormat

Answer 2

If the +0 prefix is a constant, then you can just quote it using singlequotes.

String string = "+020110312";
Date date = new SimpleDateFormat("'+0'yyyyMMdd").parse(string);
System.out.println(date); // Sat Mar 12 00:00:00 GMT-04:00 2011

(outcome is correct as per my timezone)

Note that months are represented by MM not mm . The mm represents minutes. Using mm for months would corrupt the parsing outcome.

See also:

• SimpleDateFormat javadoc

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Update : since that seem to vary in the future "but in future it may be more than one zeros" , you can better consider to substring the last 8 characters.

String string = "+020110312";
Date date = new SimpleDateFormat("yyyyMMdd").parse(string.substring(string.length() - 8));
System.out.println(date); // Sat Mar 12 00:00:00 GMT-04:00 2011

Answer 3

I would substring the last 8 chars from your representation and then parse it. (I am not sure if you can safely avoid it)

Answer 4

You could parse the date portion using SimpleDateFormat.

SimpleDateFormat df = new SimpleDateFormat("yyyyMMdd");
df.parse("20110312");

But you would need to strip off the "+000" prefix.