Java中Comparable接口的用法

在Java中有一个内置的排序接口，可以很方便的排序一组数。

public class Main {
    public static void main(String[] args) {
        Duck[] ducks = { new Duck("nlack", 2), new Duck("nasdasd", 3), new Duck("red", 5), new Duck("blue", 55), new Duck("gray", 32), new Duck("gay", 10), new Duck("youo", 11) };
        Arrays.sort(ducks);
        for (Duck duck : ducks) {
            System.out.println(duck.toString());
        }
    }
}

class Duck implements Comparable<Duck> {
    private int weight;
    private String name;

    public Duck(String name, int weight) {
        this.weight = weight;
        this.name = name;
    }

    @Override
    public String toString() {
        return "Duck [weight=" + weight + ", name=" + name + "]";
    }

    @Override
    public int compareTo(Duck o) {
        if (this.weight < o.weight) {
            return -1;
        } else if (this.weight == o.weight) {
            return 0;
        } else {
            return 1;
        }
    }
}

Duck [weight=2, name=nlack]
Duck [weight=3, name=nasdasd]
Duck [weight=5, name=red]
Duck [weight=10, name=gay]
Duck [weight=11, name=youo]
Duck [weight=32, name=gray]
Duck [weight=55, name=blue]

显示的结果是从小到达的顺序，这是由compareTo方法控制的。