IllegalFormatConversionException d != java.lang.Integer when trying to printf date?

Question

public void display() {
    System.out.printf("%-10d%-12s%-12s%10.2f%8d%12.2f%1$td.%1$tm.%1$ty %n\n",
    this.getID(),
    this.getFirstName(),
    this.getLastName(),
    this.getState(),
    this.getNo(),
    this.getAmt(),
    this.getDate());
}

Is my method for printing out some of my info. this.getDate returns date as a Date (java.util.Date) type.

I had an example given to me as System.out.printf("%1$td.%1$tm.%1$ty %n", date); to print out the data in a dd.mm.yyyy format. I tried to place that into my code, but by the looks of things I made a formatting mistake?

I've been trying a few printing methods now but find it confusing how it would work on its own but then I have issues when I try to place it into a larger printf statement.

Answer 1

The issue is that the number before the $-sign indicates the absolute index (starting with 1! 😉) of the Object. You intended to point at the Date (Index 7) but pointed at the first element instead, which happend to be an Integer. You'll want to use "%-10d%-12s%-12s%10.2f%8d%12.2f%7$td.%7$tm.%7$ty %n\\n" for formatting.

Answer 2

First of all Date formatting is a complex issue and is already dealt with for you. So you trying to come up your own formatter (such as "%-10d%-12s%-12s%10.2f%8d%12.2f%td.%toString() of class Date . If you need better formatting than look at method DateFormat.format(Date date) . However, note that if you use Java 8 or higher than the class java.util.Date shouldn't be used. Look at java.time package. Use ZonedDateTime or any of its "brothers" instead of Date and use DateTimeFormatter to format it to string