经典笔试题：有一个学生集合要求按照学生的身高从低到高排序（list中的对象实现Comparable接口来实现）

package com.gaopeng.interview;

public class StudentHasComp implements Comparable<StudentHasComp> {

    private String name;

    private Integer age;

    private Integer height;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

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

    public Integer getHeight() {
        return height;
    }

    public void setHeight(Integer height) {
        this.height = height;
    }

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


    /**
     * 返回 0 表示 this == obj
     * 返回整数表示 this > obj
     * 返回负数表示 this < obj
     */
    @Override
    public int compareTo(StudentHasComp shc) {
        return this.getHeight().compareTo(shc.getHeight());
    }

}

package com.gaopeng.interview;

import java.util.ArrayList;
import java.util.Collections;

public class SortStudentHasCompByHeight {

    public static void main(String[] args) {

        StudentHasComp s1 = new StudentHasComp();
        s1.setName("张三");
        s1.setAge(18);
        s1.setHeight(185);

        StudentHasComp s2 = new StudentHasComp();
        s2.setName("李四");
        s2.setAge(15);
        s2.setHeight(172);

        StudentHasComp s3 = new StudentHasComp();
        s3.setName("王五");
        s3.setAge(22);
        s3.setHeight(179);

        ArrayList<StudentHasComp> studentList = new ArrayList<>();

        studentList.add(s1);
        studentList.add(s2);
        studentList.add(s3);

        Collections.sort(studentList);
        System.out.println(studentList);
    }
}

运行结果如下：

[Student{name='李四', age=15, height=172}, Student{name='王五', age=22, height=179}, Student{name='张三', age=18, height=185}]