对象的比较，排序，重写equals()，compareTo(),hashCode()方法

import java.util.ArrayList;
import java.util.Collections;
public class Person implements Comparable<Person>{
	private String name;
	private int age;
	private String sex;
	
	public Person(String name ,int age, String sex){
		this.name = name;
		this.age = age;
		this.sex = sex;
	}

	//重写equals方法
	public boolean equals(Object other) {
		boolean flag = false;
		if(other == null) {
			return flag;
		}
		if(this == other) {
			return !flag;
		}
		if (other instanceof Person) {
			Person p = (Person)other;
			if(!this.name.equals(p.name)) {
				return flag;
			}
			
			if(this.age != p.age) {
				return flag;
			}
			if(!this.sex.equals(p.sex)) {
				return flag;
			}
			flag = true;
		}
		return flag;
	}
	//重写hasCode
	public int hashCode() {
		return this.name.hashCode();
	}
	
	//实现compareTo接口，首先按age排序，再按name排序
	public int compareTo(Person p) {
		if(this.age > p.age){
			return 1;
		}else if(this.age < p.age) {
			return -1;
		}else{
			return this.name.compareTo(p.name);
		}
	}
	
	public static void main(String[] args) {
		Person p1 = new Person("TOM",10,"male");
		Person p2 = new Person("Mary",12,"female");
		Person p3 = new Person("TOM",10,"male");
		Person p4 = new Person("Ryan",9,"male");
		Person p5 = new Person("Aill",9,"male");
		Person p6 = new Person("Cindy",12,"female");
		
		ArrayList<Person>  list = new ArrayList<Person>();
		list.add(p2);
		list.add(p3);
		list.add(p4);
		list.add(p5);
		list.add(p6);
		
		System.out.println(p1.equals(p3));//true;
		System.out.println(p1.equals(p2));//false;
		
		Collections.sort(list);
		for (Person p : list) {
			System.out.println(p.name + " " + p.age + " " + p.sex);
		}
		
		/*打印结果
		  Aill 9 male
		  Ryan 9 male
		  TOM 10 male
		  Cindy 12 female
		  Mary 12 female
		 */	
	}
	
}