一步一步学习java数组学习(ch5)对象数组的排序

public class Test{
    public static void main(String[] args){
            Date[] days = new Date[5];
            days[0] = new Date(2006,5,4);
            days[1] = new Date(2006,7,4);
            days[2] = new Date(2008,5,4);
            days[3] = new Date(2004,5,9);
            days[4] = new Date(2004,5,4);
            bubbleSort(days);
            for(int i=0;i<days.length;i++){
                System.out.println(days[i]);                //调用了tostring方法
            }
    }    
    
    public static Date[] bubbleSort(Date[] a){            //冒泡排序    
            for(int i = a.length-1;i>=1;i--){                        //从数组最后一个开始
                for(int j = 0;j<=i-1;j++){
                    if(a[j].compare(a[j+1])>0){                            //调用了date类的compare方法
                        Date tmp = a[j];
                        a[j] = a[j+1];
                        a[j+1] = tmp;
                    }
                }    
            }
            return a;
            
    }
}
class Date{
        private int day,month,year;
        Date(int year,int month,int day){
            this.day = day;
            this.month = month;
            this.year = year;
        }
        
        public int compare(Date d){
            return year > d.year? 1
                         :year < d.year? -1
                         :month > d.month? 1
                         :month > d.month? -1
                         :day > d.day? 1
                         :day < d.day? -1 : 0;
        }
        public String toString(){                                    //重写object类的tostring方法
            return "year:month:day"+this.year+"-"+this.month+"-"+this.day;
        }
}

 

今天学习的创建对象数组，然后通过对象的比较方法排序。。

执行结果如下