java中map使用非系统类作为key

import java.util.Map ;
import java.util.HashMap ;
class Person{
private String name ;
private int age ;
public Person(String name,int age){
this.name = name ;
this.age = age ;
}
public String toString(){
return "姓名：" + this.name + "；年龄：" + this.age ;
}
public boolean equals(Object obj){
if(this==obj){
return true ;
}
if(!(obj instanceof Person)){
return false ;
}
Person p = (Person)obj ;
if(this.name.equals(p.name)&&this.age==p.age){
return true ;
}else{
return false ;
}
}
public int hashCode(){
return this.name.hashCode() * this.age ;
}
};
public class HashMapDemo08{
public static void main(String args[]){
Map<Person,String> map = null ;
map = new HashMap<Person,String>() ;
map.put(new Person("张三",30),"zhangsan");	// 增加内容
System.out.println(map.get(new Person("张三",30))) ;
}
};