Java IdentityHashMap重复值的输出问题

package org13.example;

import java.util.IdentityHashMap;

import java.util.Iterator;

import java.util.Map;

import java.util.Set;

class Man{

 private String name;

 private int age;

 public Man(String name,int age){

  this.setName(name);

  this.setAge(age);

 }

 public void setName(String name){

  this.name = name;

 }

 public String getName(){

  return name;

 }

 public void setAge(int age){

  this.age = age;

 }

 public int getAge(){

  return age;

 }

 public boolean equals(Object obj){

  if(this==obj){

   return true;

  }

  if(!(obj instanceof Man)){

   return false;

  }

  Man p = (Man)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 String toString(){

  return "姓名:"+this.name+"\t年龄:\n"+this.age;

 }

}

public class IdentityHashDemo01 {

 public static void main(String[] args) {

  Map<Man,String> map = null;

  map =new IdentityHashMap<Man,String>();

  map.put(new Man("张三",20),"zhangsan1");

  map.put(new Man("李四",20),"zhangsan2");

  map.put(new Man("张三",20),"zhangsan3");

  Set<Map.Entry<Man,String>> allset =null;

  allset =map.entrySet();

  Iterator<Map.Entry<Man,String>> allIter =null;

  allIter = allset.iterator();

  while(allIter.hasNext()){

   Map.Entry<Man,String> me = allIter.next();

   System.out.println(map.get(me.getKey()+"--->"+me.getValue()));

  }

 }

}

为什么输出的都是null？求大神指教