public class Goods {//商品实体类private String number;//商品编号private String name;//商品价格private  double price;//商品单价private  int quantity;//商品数量public void setNumber(String number) {this.number = number;}public String getNumber() {return number;}public void setName(String name) {this.name = name;}public String getName() {return name;}public void setPrice(double price) {this.price = price;}public double getPrice() {return price;}public void setQuantity(int quantity) {this.quantity = quantity;}public int getQuantity() {return quantity;}
}

测试结果

//treeset
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.util.UUID;//set接口
public class test60{public static void main(String[] args){//Set goodsset=new HashSet(18);//初始容量，不够用会自动扩展Set goodsset=new HashSet(16);Goods goods0=new Goods();goods0.setName("肥皂");goods0.setNumber(UUID.randomUUID().toString());goods0.setQuantity(20000);Goods goods1=new Goods();goods1.setName("洗发水");goods1.setNumber(UUID.randomUUID().toString());goods1.setQuantity(20000);Goods goods2=new Goods();goods2.setName("运动鞋");goods2.setNumber(UUID.randomUUID().toString());goods2.setQuantity(20000);Goods goods3=new Goods();goods3.setName("运动鞋");goods3.setNumber(UUID.randomUUID().toString());goods3.setQuantity(2000);goodsset.add(goods2);goodsset.add(goods1);goodsset.add(goods0);goodsset.add(goods3);Iterator iterator=goodsset.iterator();while(iterator.hasNext()){Goods g=(Goods)iterator.next();System.out.println(g.getName()+"\t"+g.getNumber()+"\t"+g.getQuantity());}for(Object O:goodsset){System.out.println(((Goods)O).getName());}//将set集合中的所有元素封装为Object数组返回Object[] objs=goodsset.toArray();for(int i=0;i<objs.length;i++){System.out.println(((Goods)objs[i]).getName());}}
}

测试结果