Java中Comparator比较器的使用

说几点需要注意的，提醒自己即可：
以下是单独定义一个比较器的类，实现了Comparator中的compare方法。（要在Main方法外面定义类噢）
一定是compare而不是Compare哦

package xixixi;
import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		Student[] arr = new Student[n];
		for(int i=0;i<n;i++)
		{
			String name = in.next();
			int num = in.nextInt();
			arr[i] = new Student(name, num);
		}
	}	
}

class Student{
	String name;
	int num;
	Student(String s,int n){
		name = s;
		num = n;
	}
	
    public String toString() {
		return name+"-"+num;
	}
}

 class NameComparator implements Comparator<Student>{
	public int compare(Student o1,Student o2)
	{
		if(o1.name.compareTo(o2.name)>0)
			return 1;
		else if(o1.name.compareTo(o2.name)<0)
			return -1;
		else 
			return o1.name.compareTo(o2.name);
	}
}