Comparable的使用（用于Arrays.sort）

package snippet;
import java.util.Arrays;
/**
 * 使用Comparable接口：让待排序对象所在的类实现Comparable接口，并重写Comparable接口中的compareTo()方法
 * 缺点是只能按照一种规则排序
 * @author tong
 *
 */
public class Compara {

    public static void main(String[] args) {
        Person[] persons = new Person[5];
        persons[0] =new Person("tom",45);
        persons[1] =new Person("jack",12);
        persons[2] =new Person("bill",21);
        persons[3] =new Person("kandy",34);
        persons[4] =new Person();
        //关键
        Arrays.sort(persons);
        for (Person person:persons) {
            System.out.println(person);
        }
    }
}

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下面是继承Comparable的Person类：

package snippet;

class Person implements Comparable<Person>{
    private String name;
    private int age;

    public Person(String name,int age){
        this.name = name;
        this.age = age;
    }
    public Person(){
        this("unknown", 0);
    }

    //重写Student类的toString()方法，在输入对象时按照以下方式输出
    @Override
    public String toString() {      
        return "Person[name:"+name+",age:"+age+"]";
    }

    //重写该类的compareTo()方法，使其按照从小到大顺序排序
    @Override
    public int compareTo(Person o) {
         return age-o.age;
    }
}

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输出结果：

Person[name:unknown,age:0]
Person[name:jack,age:12]
Person[name:bill,age:21]
Person[name:kandy,age:34]
Person[name:tom,age:45]

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