用冒泡排序对Date类数组排序

public class TestDateSort {

    public static void main(String[] args) {
        Date[] days = new Date[5];
        days[0] = new Date(2016, 5, 1);
        days[1] = new Date(2016, 7, 1);
        days[2] = new Date(2018, 5, 4);
        days[3] = new Date(2014, 5, 9);
        days[4] = new Date(2014, 5, 4);
        
        System.out.println("排序前: ");
        for(int i=0; i<days.length; i++) {
            System.out.println(days[i]);
        }
        
        bubbleSort(days);    //调用冒泡排序
        
        System.out.println("排序后: ");
        for(int i=0; i<days.length; i++) {
            System.out.println(days[i]);
        }
        
    }

    //冒泡排序Date[]
    private static void bubbleSort(Date[] days) {
        int len = days.length-1;    //定义len为数组长度减一
        
        for(int i = len; i > 0; --i ) {
            for(int j = 0; j < i; ++j) {
                if(days[j].compare(days[j+1])>0) { 
                    Date temp = days[j];
                    days[j] = days[j+1];
                    days[j+1] = temp;
                }
            }
        }        
    }
    
}

//定义一个Date类
class Date{
    int year, month, day;
    
    //构造方法
    Date(int year, int month,int day){
        this.year = year;
        this.month = month;
        this.day = day;
    }
    
    //按年、月、日比较Date的方法
    public int compare(Date date) {
        return year > date.year ? 1
               : year < date.year ? -1
               : month > date.month ? 1
               : month < date.month ? -1
               : day > date.day ? 1
               : day < date.day ? -1 : 0;
      }
    
    //重写toString()方法，按照重写的方式输出
    @Override
    public String toString() {
        return "Year:Month:Day -- " + year + "-" + month + "-" + day;
    }
        
}

 输出结果:

排序前:
Year:Month:Day -- 2016-5-1
Year:Month:Day -- 2016-7-1
Year:Month:Day -- 2018-5-4
Year:Month:Day -- 2014-5-9
Year:Month:Day -- 2014-5-4
排序后:
Year:Month:Day -- 2014-5-4
Year:Month:Day -- 2014-5-9
Year:Month:Day -- 2016-5-1
Year:Month:Day -- 2016-7-1
Year:Month:Day -- 2018-5-4