package date;

package date;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class GetLastMonthOrYear {
    //上个月的现在
    public static String getNowOfLastMonth() {
        // Date Format will be display
        SimpleDateFormat aSimpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
        GregorianCalendar aGregorianCalendar = new GregorianCalendar();
        // Get last month GregorianCalendar object
        aGregorianCalendar.set(Calendar.MONTH, aGregorianCalendar
                .get(Calendar.MONTH) - 1);
        // Format the date to get year and month
        String nowOfLastMonth = aSimpleDateFormat
                .format(aGregorianCalendar.getTime());
        return nowOfLastMonth;
    }
   
    //去年的现在
    public static String getNowOfLastYear() {
        // Date Format will be display
        SimpleDateFormat aSimpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
        GregorianCalendar aGregorianCalendar = new GregorianCalendar();
        // Get last month GregorianCalendar object
        aGregorianCalendar.set(Calendar.YEAR, aGregorianCalendar
                .get(Calendar.YEAR) - 1);
        // Format the date to get year and month
        String currentYearAndMonth = aSimpleDateFormat
                .format(aGregorianCalendar.getTime());
        return currentYearAndMonth;
    }

    public static void main(String[] args) {
        System.out.println(GetLastMonthOrYear.getNowOfLastMonth());
        System.out.println(GetLastMonthOrYear.getNowOfLastYear());
    }
}
比如今天是2007年09月26
输出：
2007-08-26
2006-09-26