Calculate the leap year in Java

Possible Duplicate:
Java Code for calculating Leap Year, is this code correct?

This was homework, and I have already received my grade, but I did not implement leap years in my code. This is a simple program that displays the numbers in a month based on user input. The only thing is I can't figure out is a way to implement a leap year that would get 29 days for February rather than 28, without writing multiple if statements. Surely there is an easier way? Here is the code:

//Displays number of days in a month

package chapter_3;

import java.util.Scanner;

public class Chapter_3 {

public static void main(String[] args) {
System.out.println("This program will calculate \n"
+ "the number of days in a month based upon \n"
+ "your input, when prompted please enter \n"
+ "the numerical value of the month you would like\n"
+ "to view including the year. Example: if you would like\n"
+ "to view March enter 3 2011 and so on.");

Scanner input = new Scanner(System.in);

//Prompt user for month and year
System.out.print("Please enter the month and year: ");
int month = input.nextInt();
int year = input.nextInt();

if (month == 1) {
System.out.println("January " + year + " has 31 days");
}
else if (month == 2) {
System.out.println("February " + year + " has 28 days");
}
else if (month == 3) {
System.out.println("March " + year + " has 31 days");
}
else if (month == 4) {
System.out.println("April " + year + " has 30 days");
}
else if (month == 5) {
System.out.println("May " + year + " has 31 days");
}
else if (month == 6) {
System.out.println("June " + year + " has 30 days");
}
else if (month == 7) {
System.out.println("July " + year + " has 31 days");
}
else if (month == 8) {
System.out.println("August " + year + " has 31 days");
}
else if (month == 9) {
System.out.println("September " + year + " has 30 days");
}
else if (month == 10) {
System.out.println("October " + year + " has 30 days");
}
else if (month == 11) {
System.out.println("November " + year + " has 30 days");
}
else if (month == 12) {
System.out.println("December " + year + " has 31 days");
}
else {
System.out.println("Please enter the numerical value "
+ "of the month you would like to view");
}
}
}

If you use the GregorianCalendar, you could do as below

Determines if the given year is a leap year. Returns true if the given year is a leap year. To specify BC year numbers, 1 - year number must be given. For example, year BC 4 is specified as -3.

GregorianCalendar cal = new GregorianCalendar();

if(cal.isLeapYear(year))
{
System.out.print("Given year is leap year.");
}
else
{
System.out.print("Given year is not leap year.");
}