Comparable接口的实现：

今天项目用到进行金额排序，之前学过的java基础有点忘记，补充一下

没有实现Comparable接口时，取出来的值无法排序

public static void main(String[] args) {

        Good1[] arr1 = new Good1[5];
        arr1[0] = new Good1("大哥",10.0);
        arr1[1] = new Good1("二弟",40.0);
        arr1[2] = new Good1("三弟",200.0);
        arr1[3] = new Good1("四弟",900.0);
        arr1[4] = new Good1("五弟",60.0);

        System.out.println("====没有实现实现Comparab接口时输出====");
        System.out.println(Arrays.asList(arr1));

    }

运行得到的结果：

如果进行排序：

Good1[] arr1 = new Good1[5];
        arr1[0] = new Good1("大哥",10.0);
        arr1[1] = new Good1("二弟",40.0);
        arr1[2] = new Good1("三弟",200.0);
        arr1[3] = new Good1("四弟",900.0);
        arr1[4] = new Good1("五弟",60.0);
        
		Arrays.sort(arr1);
        System.out.println("====没有实现实现Comparab接口时输出====");
        System.out.println(Arrays.asList(arr1));

报错

实现接口进行排序：

Controller层的实现

public static void main(String[] args) {
        Good[] arr = new Good[5];
        arr[0] = new Good("大哥",10.0);
        arr[1] = new Good("二弟",40.0);
        arr[2] = new Good("三弟",200.0);
        arr[3] = new Good("四弟",900.0);
        arr[4] = new Good("五弟",60.0);

        Arrays.sort(arr);
        System.out.println("====实现Comparab接口时输出====");
        System.out.println(Arrays.asList(arr));

    }

实体类的实现

@Data
public class Good implements Comparable<Good>{
    private String name;
    private Double price;

    public Good(String name, Double price) {
        this.name = name;
        this.price = price;
    }

//重写比较方法
//如果当前对象大于形参对象，返回1
//如果当前对象小于形参对象。返回-1
//如果相等，返回0
    @Override
    public int compareTo(Good o) {
        if (this.price>o.price)
            return 1;
        else if (this.price<o.price)
            return -1;
        else
            return 0;
    }
}

成功实现：

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复习时间：

2023/08/12