计算两个日期之间相差的月数 博客分类： Java java计算两个日期之间相差的月数

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class Main {

	/**
	 * 得到两日期相差几个月
	 * 
	 * @return
	 */
	public static long getMonth(String date1, String date2) {
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		int result = 0;
		Calendar c1 = Calendar.getInstance();
		Calendar c2 = Calendar.getInstance();

		try {
			c1.setTime(sdf.parse(date1));
			c2.setTime(sdf.parse(date2));
			result = c2.get(Calendar.MONTH) - c1.get(Calendar.MONTH);
		} catch (ParseException e) {
			e.printStackTrace();
		}

		return result == 0 ? 1 : Math.abs(result);
	}
    
    /**
     * 计算两个日期之间相差的月数
     * 
     * @param date1
     * @param date2
     * @return
     */
    public static int getMonth(Date date1, Date date2) {
        int iMonth = 0;
        int flag = 0;
        try {
            Calendar cal1 = Calendar.getInstance();
            cal1.setTime(date1);

            Calendar cal2 = Calendar.getInstance();
            cal2.setTime(date2);

            if (cal2.equals(cal1)) return 0;
            if (cal1.after(cal2)) {
                Calendar temp = cal1;
                cal1 = cal2;
                cal2 = temp;
            }
            if (cal2.get(Calendar.DAY_OF_MONTH) < cal1.get(Calendar.DAY_OF_MONTH)) flag = 1;

            if (cal2.get(Calendar.YEAR) > cal1.get(Calendar.YEAR))
                iMonth = ((cal2.get(Calendar.YEAR) - cal1.get(Calendar.YEAR)) * 12 + cal2.get(Calendar.MONTH) - flag)
                         - cal1.get(Calendar.MONTH);
            else iMonth = cal2.get(Calendar.MONTH) - cal1.get(Calendar.MONTH) - flag;

        } catch (Exception e) {
            e.printStackTrace();
        }
        return iMonth;
    }

}