Left padding an integer with zero (Java)

Question

I have checked and apparently you can't left-pad zero onto an integer. Converting to string and back to integer doesn't work either. Although, what I am trying to do is use the integer for a FOR loop and then send into a JPQL query, using concatenation, which needs the date format to be in XML Gregorian Calendar(YYYY-MM-DD HH:MM:SS).

One way to solve my problem would be to use formatter before sending it into a JPQL query. What I mean to ask is : Is there a better way to do this, in my case?

Here is the relevant piece of code:

for (int month = startMonth; month <= endMonth; month++) {

                    inputDates = "SELECT COUNT(d) FROM Datafile d WHERE d.datafileCreateTime BETWEEN {ts  2013-" +month+ "-01 00:00:00}  AND {ts 2013-" +month+ "-02 23:59:59}";
                    ...

Did you even bother to read something about `String.format()` ?? — Antoniossss, Aug 12 '14 at 14:54
I would look into the `format` class which will let you specify the number of characters a number has before and after decimals. This should let you achieve what you want. — JustWannaFly, Aug 12 '14 at 14:56
Is http://docs.oracle.com/javase/6/docs/api/java/text/DecimalFormat.html what you are looking for? You can convert an int into a two digit number with leading zeros. — JustinKSU, Aug 12 '14 at 14:56
Hard to tell what this is a duplicate of, since the question starts out about left padding integers with zeros but turns into formatting a date. — David Conrad, Aug 12 '14 at 15:38
Is there some way to use a GROUP BY in the SQL query, rather than running multiple queries to get the results by month? — David Conrad, Aug 12 '14 at 15:40
@DavidConrad thanks, but the query seems to accept using formatter. Also I am using JPQL, and I think SQL is different, right? I don't know too much as I only started recently. — zack2313, Aug 12 '14 at 15:57

Adrian · Accepted Answer · 2014-08-12T14:58:17.543

4

How about this:

String.format("%010d", 123456);

Details: Formatter

or

org.apache.commons.lang.StringUtils.leftPad("123456", 10, "0");

Details: StringUtils

edited Aug 12 '14 at 14:58

answered Aug 12 '14 at 14:56

Adrian

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score 1 · Answer 2 · answered Aug 12 '14 at 15:05

If I understand your question, you need a Date in a specific format, I would recommend using a SimpleDateFormat. That is, something like -

DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String date = sdf.format(new Date());
System.out.println(date);

Output is

2014-08-12 11:06:19

Left padding an integer with zero (Java)

2 Answers2