1. API設計

2. Comparable介面
需求：
（1）定義一個學生類Student，具有年齡age和姓名username兩個屬性，並通過Comparable介面提供比較規則；
（2）定義測試類Test，在測試類Test中定義測試方法Comparable getMax(Comparable c1,Comparable c2)完成測試。
程式碼：

package sort;
//學生類
public class Student implements Comparable<Student>{
    private String username;
    private int age;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Student() {
        super();
    }

    @Override
    public String toString() {
        return "Student{" +
                "username='" + username + '\'' +
                ", age=" + age +
                '}';
    }

    @Override
    public int compareTo(Student o) {
        return this.getAge()-o.getAge();
    }
}
 

package test;

import sort.Student;
//測試類
public class Test {
    public static void main(String[] args) {
        Student stu1 = new Student();
        stu1.setUsername("zhangsan");
        stu1.setAge(17);
        Student stu2 = new Student();
        stu2.setUsername("lisi");
        stu2.setAge(19);
        Comparable max = getMax(stu1, stu2);
        System.out.println(max);
    }
    //測試方法，獲取兩個元素中的較大值
    public static Comparable getMax(Comparable c1,Comparable c2){
        int cmp = c1.compareTo(c2);
        if (cmp>=0){
            return c1;
        }else{
            return c2;
        }
    }
}

 

3. 結果