购物时，如果购买的商品在超市中有，则提示购物者买到了某商品，
否则提示什么都没买到。

//商品类
public class Product {
  //定义商品名称
  private String proName;
  //get方法
  public String getProductName() {
    return proName;
  }
  //set方法
  public void setProduct(String proName) {
    this.proName = proName;
  }
}

//超市类
public class Supermarket {
  //1.定义超市名称,设置方法
  private String supermaketName;
  public String getSupermaketName() {
    return supermaketName;
  }
  public void setSupermaketName(String supermaketName) {
    this.supermaketName = supermaketName;
  }
  //2.定义货架数组
  private Product[] productArr;
  public Product[] getProductArr() {
    return productArr;
  }
  public void setProductArr(Product[] productArr) {
    this.productArr = productArr;
  }
  //3.卖货方法
  Product sell(String name) {//传入要购买的商品名称
    for(int i=0; i<productArr.length; i++) {//遍历商品数组
      if(productArr[i].getProductName()==name) {
        return productArr[i];
      }
    }
    return null;
  }
}

//购物者类
public class Person {
  //1.定义人名字
  private String personName;
  public String getPersonName() {
    return personName;
  }
  public void setPersonName(String personName) {
    this.personName = personName;
  }
  //2.购买方法
  Product shopping(Supermarket market,String name) {//传入超市和商品名
    return market.sell(name);//调用超市类卖货方法返回结果
  }
}

public class Shopping {
  public static void main(String[] args) {
    //1.创建商品对象
    Product p1 = new Product();
    Product p2 = new Product();
    Product p3 = new Product();
    Product p4 = new Product();
    Product p5 = new Product();
    Product p6 = new Product();
    //2.调用商品类set方法赋值
    p1.setProduct("花田果酒");
    p2.setProduct("菠萝蜜");
    p3.setProduct("百事可乐");
    p4.setProduct("乐事薯片");
    p5.setProduct("康师傅金汤肥牛面");
    p6.setProduct("红太狼专属平底锅");
    //3.创建超市对象
    Supermarket s1 = new Supermarket();
    Supermarket s2 = new Supermarket();
    Supermarket s3 = new Supermarket();
    //4.调用set赋值
    s1.setSupermaketName("家乐福");
    s1.setProductArr(new Product[] {p1,p2,p3,p4,p5,p6});
    s2.setSupermaketName("大润发");
    s2.setProductArr(new Product[] {p1,p2,p3,p4,p5,p6});
    s3.setSupermaketName("沃尔玛");
    s3.setProductArr(new Product[] {p1,p2,p3,p4,p5,p6});
    //5.创建人对象
    Person n1 = new Person();
    Person n2 = new Person();
    Person n3 = new Person();
    //6.调用set方法赋值
    n1.setPersonName("张艺兴");
    n2.setPersonName("刘德华");
    n3.setPersonName("杨幂");
    n3.shopping(s2,"杨幂");
    Product result = s2.sell("康师傅金汤肥牛面");
    if(result == null) {
      System.out.println("Emmmmmm,"+n3.getPersonName()+"逛了一圈"+s2.getSupermaketName()+"超市，居然什么也没买到");
    }else {
      System.out.println(n3.getPersonName()+"逛了一圈"+s2.getSupermaketName()+"超市后，买到了传说中的"+result.getProductName());
    }
  }
}