開發過程中如果我們想讓某個物件是可比較大小的，那麼需要實現Comparable這個介面。

舉例：我們根據滑鼠的價格進行排序，如果價格一樣再根據滑鼠的名稱來進行排序。

class Mouse implements Comparable{
   

    String goodsName;
    int price;

    public Mouse(String name,int price){
        this.goodsName = name;
        this.price = price;
    }

    @Override
    public int compareTo(Object o) {
        
 
if (o instanceof Mouse){
            Mouse mouse = (Mouse) o;
            if (this.price > mouse.price){
                return 1;
            }else if(this.price < mouse.price){
                return -1;
            }else {
                //價格一樣按照貨物名稱排
                return -this.goodsName.compareTo(mouse.goodsName);
            }

        }
 
else {

            throw new RuntimeException("傳入的不是滑鼠型別");
        }
    }

    @Override
    public String toString() {
        return "Mouse{" +
                "goodsName='" + goodsName + '\'' +
                ", price=" + price +
                '}';
    }
}

@Test
    public void test1(){
        Mouse[] li 
 
= new Mouse[5];
        li[0] = new Mouse("XiaoMi",20);
        li[1] = new Mouse("Logitech",50);
        li[2] = new Mouse("lenove",30);
        li[3] = new Mouse("dell",25);
        li[4] = new Mouse("Huawei",50);
        Arrays.sort(li);
        System.out.println(Arrays.toString(li));
    }

這裡如果價格一樣按照貨物名稱從高到底進行排序，輸出結果為

[Mouse{goodsName='XiaoMi', price=20}, Mouse{goodsName='dell', price=25}, Mouse{goodsName='lenove', price=30}, Mouse{goodsName='Logitech', price=50}, Mouse{goodsName='Huawei', price=50}]