Java计算两个日期相差天数

import java.util.*;
 
public class Test {
    public static void main(String args[]) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(new Date());
 
        calendar.set(1991, 7, 7);
        long time_1 = calendar.getTimeInMillis();
 
        calendar.set(2012, 8, 31);
        long time_2 = calendar.getTimeInMillis();
 
        long space = (time_2 - time_1) / (1000 * 60 * 60 * 24);
        System.out.println("至今我活了大约 " + space + " 天");
    }
}