计算两个时间相差几个月

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

public class Time2 {

	public static void main(String[] args) {
		Date date = new Date();
		DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		Calendar c1 = Calendar.getInstance();
		//c1.setTimeInMillis(System.currentTimeMillis());
		
		c1.setTime(date);
		System.out.println(df.format(c1.getTime()));
		c1.add(Calendar.MONTH, 3); 
		System.out.println(df.format(c1.getTime()));
		
		Date date2 = c1.getTime();
		
		boolean flag = true; 
			int temp = 1;
			int i=0;
			while(flag){
				Calendar cal = Calendar.getInstance();    
				Date te = date;
				cal.setTime(te);
				cal.add(Calendar.MONTH, temp);  //将当前日期加一个月  
				 
				Date da = cal.getTime(); 
				if(date2.before(da)) {
					//System.out.println(df.format(date1) + ".. " + df.format(da));
					flag = false;
				} else {
					++temp; 
					++i;
				}
			};
			System.out.println(i + "  相差的月: " +temp);  
	}
	
	public static void test2(){
		Date date = new Date();
		DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		Calendar c1 = Calendar.getInstance();
		//c1.setTimeInMillis(System.currentTimeMillis());
		
		c1.setTime(date);
		System.out.println(df.format(c1.getTime()));
		c1.add(Calendar.MONTH, 1); 
		System.out.println(df.format(c1.getTime()));
	} 
	
}


public static void main(String[] args) {

	boolean flag = true;
	DateFormat df = new SimpleDateFormat("yyyy-MM-dd"); // HH:mm:ss
	Calendar c1 = null;
	try {
		c1 = Calendar.getInstance();
		Date date = df.parse("2009-09-30");		
		c1.setTime(date);	
	} catch (ParseException e) {
		e.printStackTrace();
	}

	Date da = c1.getTime();
	Date now = new Date();
	int temp =0;
	if (!now.before(da)) {

		temp =1;
		while (flag) {

			Date temp_date = c1.getTime();
			c1.add(Calendar.YEAR, 1); // 将当前日期加一个月

			temp_date = c1.getTime();
			if (now.before(temp_date)) {
				
				flag = false;
			} else{

				++temp;
			}
		};
	}
	System.out.println("  相差的几年: " + temp);
}