JAVA 如何在本练习中使用 compareTo 比较整数

Question

我正在尝试做这个练习：我有一个学生有名字、姓氏和编号，我想按编号给学生排序。如果我想按名字或姓氏排序，这似乎很容易但有了数字我不知道该怎么做.. 这是我的代码：

public class Student implements Comparable<Student> {
private String name;
private String surname;
private int number;


public Student(String n, String s, int m) {
    name = n;
    surname = s;
    number = m;
}

public String getName() {
    return name;
}

public String getSurname() {
    return surname;
}

public int getmatricola() {
    return number;
}
//CompareTo Name
public int compareTo(Student otherObject) {
    return name.compareTo(otherObject.getName());
}
}
//TESTER
 ArrayList<Student> list = new ArrayList<Student>(); 
 System.out.print("\n ORDER BY NUMBER \n");

    Collections.sort(list);
    for (int i = 0; i < list.size(); i++) {
        Student s = list.get(i);
        String std = s.getAll();
        System.out.println(std);


    }

Answer 1

那么为什么你的数字是一个整数你可以减去数字和 return 差值：

public class Student implements Comparable<Student> {
private String name;
private String surname;
private int number;


public Student(String n, String s, int m) {
    name = n;
    surname = s;
    number = m;
}

public String getName() {
    return name;
}

public String getSurname() {
    return surname;
}

public int getmatricola() {
    return number;
}
//CompareTo number
public int compareTo(Student otherObject) {
    return number - otherObject.getmatricola();
}
}

Answer 2

你可以实现类似的东西：

public int compareTo(Student otherObject) {
    return Integer.compare(this.number, otherObject.getNumber());
}

Answer 3

尝试这样做...应该有效 //比较名称 public int compareTo(Student otherObject) { 如果( this.getmatricola() > otherObject.getmatricola()) return 1; 别的 return-1； }

JAVA 如何在本练习中使用 compareTo 比较整数

JAVA How to compare integer using compareTo in this exercise

java

compareto