java对象排序

java 对象排序，也是根据对象某个属性进行排序   例如：苹果对象排序，以大小为根据

import java.lang.reflect.Array;
import java.util.*;

/**
 * Created by Bright on 2017/7/2.
 */
public class compareTest {
    public static void main(String[] args) {
        List<Apple> apples = new ArrayList<Apple>();
        apples.add(new Apple(2));
        apples.add(new Apple(3));
        apples.add(new Apple(1));
        apples.add(new Apple(5));

        Collections.sort(apples, new Apple());

        System.out.println(apples);


    }
}

class Apple implements Comparator<Apple>{

    private int size;

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }

    public Apple(){

    }
    public Apple(int size) {
        this.size = size;
    }

    @Override
    public int compare(Apple o1, Apple o2) {
        return Integer.compare(o1.getSize(),o2.getSize());
    }

    @Override
    public String toString() {
        return "Apple{" +
                "size=" + size +
                '}';
    }
}
排序后输出：

[Apple{size=1}, Apple{size=2}, Apple{size=3}, Apple{size=5}]