HashSet集合的特点：元素是具备唯一性的，每次存储都要先算出哈希值，看有没相同，没有相同的存储到相应的位置，如果相同则再判断存储进来的值是否与被比较的相同，如果相同，则不再存储，不同就存储

package com.java.b.customer.www;

public class Customer {
 private String name;
 private int age;
 
 public Customer() {
  super();
 }

public Customer(String name, int age) {
  super();
  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 "Customer [name=" + name + ", age=" + age + "]";
 }

@Override
 public int hashCode() {
  final int prime = 31;
  int result = 1;
  result = prime * result + age;
  result = prime * result + ((name == null) ? 0 : name.hashCode());
  return result;
 }

@Override
 public boolean equals(Object obj) {
  if (this == obj)
   return true;
  if (obj == null)
   return false;
  if (getClass() != obj.getClass())
   return false;
  Customer other = (Customer) obj;
  if (age != other.age)
   return false;
  if (name == null) {
   if (other.name != null)
    return false;
  } else if (!name.equals(other.name))
   return false;
  return true;
 }

package com.java.c.set.www;

import java.util.HashSet;
import java.util.Iterator;

import com.java.b.customer.www.Customer;

public class HashSetDmeo {

public static void main(String[] args) {
  //创建一个hashSet容器
  HashSet set=new HashSet();
  //添加元素
  set.add(new Customer("小张1",25));
  set.add(new Customer("小李2",20));
  set.add(new Customer("小李4",29));
  set.add(new Customer("小火5",17));
  set.add(new Customer("小李2",20));
  for (Iterator it = set.iterator(); it.hasNext();) {
   System.out.println(it.next());  
  }
 }

}