Dateadd(String str,int count)//str为形如yyyy-mm-dd的字符串格式的日期，count为给月份加的整数值。代码如下:

package java_Thread;

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

public class myDate {
    public static void main(String[] args) throws ParseException{
        Dateadd("2008-8-31",6);
    }
    
    public static void Dateadd(String str,int count) throws ParseException{ //str 类型为 yyyy-mm-dd
        Date df = DateFormat.getDateInstance(2).parse(str);
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(df);
        show(calendar.getTime());
        calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH) + count);
        show(calendar.getTime());
    }
    public static void show(Date a){
        DateFormat df2 = DateFormat.getDateInstance(2);
        System.out.println(df2.format(a));
    }
}

结果如下:

2008-8-31
2009-3-3