Arrays.sort可以对所有实现Comparable的对象进行排序。但如果有多种排序需求，如有时候需对name进行降序排序，有时候只需要对年龄进行排序。使用Comparable无法满足这样的需求。可以编写不同的Comparator来满足多样的排序需求。

1.编写PersonSortable2类

属性：private name(String)、private age(int)
有参构造函数：参数为name,age
toString方法：返回格式name-age

2 编写Comparator类

1. 编写NameComparator类，实现对name进行升序排序
2. 编写AgeComparator类，对age进行升序排序

3.main方法中

1. 输入n
2. 输入n行name age，并创建n个对象放入数组
3. 对数组按照name进行升序排序后输出。
4. 在3的基础上对数组按照age进行升序排序后输出。
5. 最后最后两行使用如下代码输出NameComparator与AgeComparator所实现的所有接口。

System.out.println(Arrays.toString(NameComparator.class.getInterfaces()));
System.out.println(Arrays.toString(AgeComparator.class.getInterfaces()));

输入样例:

5
zhang 15
zhang 12
wang 14
Wang 17
li 17

输出样例:

NameComparator:sort
Wang-17
li-17
wang-14
zhang-15
zhang-12
AgeComparator:sort
zhang-12
wang-14
zhang-15
Wang-17
li-17
//最后两行是标识信息

代码：

import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

class PersonSortable2 {
    private String name;
    private int age;

    public PersonSortable2(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

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

    @Override
    public String toString() {
        return name + "-" + age;
    }
}

class NameComparator implements Comparator<PersonSortable2> {
    public int compare(PersonSortable2 o1, PersonSortable2 o2) {
        return o1.getName().compareTo(o2.getName());
    }
}

class AgeComparator implements Comparator<PersonSortable2>{

    @Override
    public int compare(PersonSortable2 o1, PersonSortable2 o2) {
        return o1.getAge() - o2.getAge();
    }
}

public class Main {
    public static void main(String[] agrs) {
        Scanner cin = new Scanner(System.in);
        int n = cin.nextInt();
        PersonSortable2[] personSortable2s = new PersonSortable2[n];
        for (int i = 0; i < n; i ++ ) {
            String name = cin.next();
            int age = cin.nextInt();
            personSortable2s[i] = new PersonSortable2(name, age);
        }
        System.out.println("NameComparator:sort");
        Arrays.sort(personSortable2s, new NameComparator());
        for (int i = 0; i < n; i ++ ) {
            System.out.println(personSortable2s[i]);
        }
        System.out.println("AgeComparator:sort");
        Arrays.sort(personSortable2s, new AgeComparator());
        for (int i = 0; i < n; i ++ ) {
            System.out.println(personSortable2s[i]);
        }
        System.out.println(Arrays.toString(NameComparator.class.getInterfaces()));
        System.out.println(Arrays.toString(AgeComparator.class.getInterfaces())); 
    }
}