Java——类比较器

1、Product类

 public class Product
 {
     private int pid;
     private String name;
     private double price;

     public Product()
     {
         // TODO Auto-generated constructor stub
     }

     public Product(int pid, String name, double price)
     {
         this.pid = pid;
         this.name = name;
         this.price = price;
     }

     public int getPid()
     {
         return pid;
     }

     public void setPid(int pid)
     {
         this.pid = pid;
     }

     public String getName()
     {
         return name;
     }

     public void setName(String name)
     {
         this.name = name;
     }

     public double getPrice()
     {
         return price;
     }

     public void setPrice(double price)
     {
         this.price = price;
     }

 }

2、类比较器：重写compare方法

 public class MyCompare implements Comparator<Product> // 泛型<Product>表示该比较器只能比较Product类型
 {

     @Override
     public int compare(Product p1, Product p2)
     {
         if (p1.getPrice() < p2.getPrice())
         {
             return -1;
         }
         else if (p1.getPrice() > p2.getPrice())
         {
             return 1;
         }
         else
         // 如果价格一样，按照id排序
         {
             if (p1.getPid() < p2.getPid())
             {
                 return -1;
             }
             else if (p1.getPid() > p2.getPid())
             {
                 return 1;
             }
             else
             {
                 return 0;
             }
         }
     }

 }

3、在ArrayList中使用比较器

 public class ProductSort
 {
     public static void main(String[] args)
     {

                 Product p1 = new Product(1, "爆米花手机", 1000000.00);
         Product p2 = new Product(2, "iPhone 7s", 5088.00);
         Product p3 = new Product(3, "小米5s", 1999.99);
         Product p4 = new Product(4, "NIIT课程", 12800.00);
         Product p5 = new Product(5, "百达翡丽", 1980000.00);
         Product p6 = new Product(6, "宝玛electric", 1999.99);
         Product p7 = new Product(7, "TIIN课程", 12800.00);
                 // 获得数组准备排序
         Product[] proArr = { p1, p2, p3, p4, p5, p6, p7 };

         Arrays.sort(proArr, new MyCompare());

         for (Product p : proArr)
         {
             System.out.println(p.getPid() + " " + p.getName() + " "
                     + p.getPrice());
         }
     }
 }