[设计模式]原型模式

[设计模式]原型模式

• 原型模式的主要思想就是克隆。
• 需要克隆的类实现Cloneable接口。
• 对象使用clone()方法。

一、浅克隆

• video类

  public class Video implements Cloneable{
  
      private String title;
      private Date createTime;
  
      public Video(String title, Date createTime) {
          this.title = title;
          this.createTime = createTime;
      }
  
      @Override
      protected Object clone() throws CloneNotSupportedException {
          return super.clone();
      }
  
      @Override
      public String toString() {
          return "Video{" +
                  "title='" + title + '\'' +
                  ", createTime=" + createTime +
                  '}';
      }
  }
  

• 测试类

  public class Copy {
  
      public static void main(String[] args) throws CloneNotSupportedException {
          Date date = new Date();
  
          Video v1 = new Video("小猪佩奇",date);
          System.out.println("v1=>"+v1);
          System.out.println("v1=>"+v1.hashCode());
  
  
          Video v2 = (Video)v1.clone();
          System.out.println("v1=>"+v2);
          System.out.println("v2=>"+v2.hashCode());
  
      }
  }
  

• 运行结果

  v1=>Video{title='小猪佩奇', createTime=Sat Jun 13 12:29:03 CST 2020}
  v1=>2133927002
  v2=>Video{title='小猪佩奇', createTime=Sat Jun 13 12:29:03 CST 2020}
  v2=>1836019240
  

二、深克隆

• video类

  public class Video implements Cloneable{
  
      private String title;
      private Date createTime;
  
      public Video(String title, Date createTime) {
          this.title = title;
          this.createTime = createTime;
      }
  
      @Override
      protected Object clone() throws CloneNotSupportedException {
          Video video = (Video)super.clone();
          video.createTime = (Date)createTime.clone();
          return video;
      }
  
      @Override
      public String toString() {
          return "Video{" +
                  "title='" + title + '\'' +
                  ", createTime=" + createTime +
                  '}';
      }
  }
  

• 测试类

  public class Copy {
  
      public static void main(String[] args) throws CloneNotSupportedException {
          Date date = new Date();
  
          Video v1 = new Video("小猪佩奇",date);
          System.out.println("v1=>"+v1);
          System.out.println("v1=>"+v1.hashCode());
  
  
          Video v2 = (Video)v1.clone();
          System.out.println("v2=>"+v2);
          System.out.println("v2=>"+v2.hashCode());
  
          System.out.println("==================================");
          date.setTime(22222222);
  
          System.out.println("v1=>"+v1);
          System.out.println("v1=>"+v1.hashCode());
  
          System.out.println("v2=>"+v2);
          System.out.println("v2=>"+v2.hashCode());
  
  
  
      }
  }
  

• 运行结果

  v1=>Video{title='小猪佩奇', createTime=Sat Jun 13 12:38:10 CST 2020}
  v1=>2133927002
  v2=>Video{title='小猪佩奇', createTime=Sat Jun 13 12:38:10 CST 2020}
  v2=>1836019240
  ==================================
  v1=>Video{title='小猪佩奇', createTime=Thu Jan 01 14:10:22 CST 1970}
  v1=>2133927002
  v2=>Video{title='小猪佩奇', createTime=Sat Jun 13 12:38:10 CST 2020}
  v2=>1836019240