尝试使用SimpleDateFormat将字符串数字“ 7”转换为07:00格式

Question

I've got the next java code:

    SimpleDateFormat formatter = new SimpleDateFormat("kk:mm");
    Date rangoInicio = formatter.parse(filtroHorariosIda.get(0));  

The value for filtroHorariosIda.get(0) is "7" (quotes includes because it's a string)

The problem is java throws the exception

java.text.ParseException Unparseable date: "7"

I've been reading the java docs and I think it's a perfectly parsing operation. Where's the problem?

Thanks.

Answer 1

I don't quite understand... kk:mm expects something in the format, well kk:mm. You're giving it "7". Shouldn't you pass "7:21" instead (or "7:00" in this case)?

Answer 2

your parse string expects an input containing ":" among other things - your input doesn't contain a ":" so of course SimpleDateFormat won't be able to interpret your input.

If your input was "7:0" it would work fine.

Answer 3

That's because you're trying to parse "7" and saying that it should use "kk:mm" format.

Try this instead

Date rangoInicio = formatter.parse(filtroHorariosIda.get(0) + ":00");  

Answer 4

For the sake of completeness, a simple test yields the following results:

public void testDateParse()
{
    String probes[] = {"7","07:00","7:00","7:0",":"}; 

    for (String probe : probes) {
        try
        {
         SimpleDateFormat formatter = new SimpleDateFormat("kk:mm");
         Date rangoInicio = formatter.parse(probe);
         System.out.println(probe + " is parsable");
        }
        catch(ParseException ex)
        {
            System.out.println(probe + " is not parsable");
        }
    }       
}

7 is not parsable

07:00 is parsable

7:00 is parsable

7:0 is parsable

: is not parsable