Java中对象比较和排序实例

（1）对Element对象进行排序（根据体重和年龄）
?（2）要想使用Arrays.sort支持排序的类必须实现Comparable接口
?
public class Elephant? implements? Comparable {
?
?
?int weight ;
?int? age? ? ;
?float tusklength;
?@Override
?public int compareTo(Object o) {
?
? Elephant? otherelephant =(Elephant) o;
? if(this.weight>otherelephant.weight){
? return 1 ;
? }
? else if(this.weight
? return -1;
? }
? else {
? return (this.age-otherelephant.age);
? }
? }
?
?
/*
?* 根据Elephant类写的一个测试类对Elephant对象根据体重和年龄进行排序
?* */
import java.util.Arrays;
public class ElephantTest {
?public static void main(String[] args) {
?Elephant elephant1 =new Elephant();
?elephant1.weight=1000;
?elephant1.age? =10;
?Elephant elephant2=new Elephant();
?elephant2.weight=200;
?elephant2.age? =200;
?
?Elephant elephant3=new Elephant();
?elephant3.weight=300;
?elephant3.age? =30 ;
?
?Elephant[] elephants =new Elephant[3];
?elephants[0]=elephant1;
?elephants[1]=elephant2;
?elephants[2]=elephant3;
?System.out.println("排序前！");
?for(Elephant? elephant:elephants){
? System.out.println("体重"+elephant.weight+":"+"年龄"+elephant.age);
?}
?Arrays.sort(elephants);
?System.out.println("排序后：");
?for(Elephant elephant:elephants){
? System.out.println("体重"+elephant.weight+":"+"年龄"+elephant.age);
?}
?}
}