1 基本概念

1、克隆的步骤

1. 实现一个接口：Cloneable。
2. 重写一个方法：clone()。

2 代码

1、案例1：浅克隆

• Video

  package prototype.demo01;
  
  import java.util.Date;
  
  public class Video implements Cloneable {
      private String name;
      private Date createTime;
  
      public Video() {
      }
  
      public Video(String name, Date createTime) {
          this.name = name;
          this.createTime = createTime;
      }
  
      public String getName() {
          return name;
      }
  
      public void setName(String name) {
          this.name = name;
      }
  
      public Date getCreateTime() {
          return createTime;
      }
  
      public void setCreateTime(Date createTime) {
          this.createTime = createTime;
      }
  
      @Override
      public String toString() {
          return "Video{" +
                  "name='" + name + '\'' +
                  ", createTime=" + createTime +
                  '}';
      }
  
      // 浅克隆
      @Override
      protected Object clone() throws CloneNotSupportedException {
          return super.clone();
      }
  }

• Bilibili

  package prototype.demo01;
  
  import org.junit.Test;
  
  import java.util.Date;
  
  /**
   * 客户端
   */
  public class Bilibili {
     /**
      * 浅克隆
      */
     @Test
     public void test() throws CloneNotSupportedException {
        // 原型对象：v1
        Date date = new Date();
        Video v1 = new Video("my video", date);
        System.out.println("v1：" + v1);
        System.out.println("v1.hashCode()：" + v1.hashCode());
        // 克隆对象：v2
        Video v2 = (Video) v1.clone();
        System.out.println("v2：" + v2);
        System.out.println("v2.hashCode()：" + v2.hashCode());
        System.out.println(v1.getCreateTime() == v2.getCreateTime());   // true
     }
  }

2、案例2：深克隆

• Video

  package prototype.demo02;
  
  import java.util.Date;
  
  public class Video implements Cloneable {
      private String name;
      private Date createTime;
  
      public Video() {
      }
  
      public Video(String name, Date createTime) {
          this.name = name;
          this.createTime = createTime;
      }
  
      public String getName() {
          return name;
      }
  
      public void setName(String name) {
          this.name = name;
      }
  
      public Date getCreateTime() {
          return createTime;
      }
  
      public void setCreateTime(Date createTime) {
          this.createTime = createTime;
      }
  
      @Override
      public String toString() {
          return "Video{" +
                  "name='" + name + '\'' +
                  ", createTime=" + createTime +
                  '}';
      }
  
      // 实现深克隆
      @Override
      protected Object clone() throws CloneNotSupportedException {
          Object obj = super.clone();
          Video v = (Video) obj;
          // 将这个对象的属性也进行克隆
          v.createTime = (Date) this.createTime.clone();
          return obj;
      }
  }

• Bilibili

  package prototype.demo02;
  
  import org.junit.Test;
  
  import java.util.Date;
  
  /**
   * 客户端
   */
  public class Bilibili {
     /**
      * 深克隆
      */
     @Test
     public void test() throws CloneNotSupportedException {
        // 原型对象：v1
        Date date = new Date();
        Video v1 = new Video("my video", date);
        System.out.println("v1：" + v1);
        System.out.println("v1.hashCode()：" + v1.hashCode());
        // 克隆对象：v2
        Video v2 = (Video) v1.clone();
        System.out.println("v2：" + v2);
        System.out.println("v2.hashCode()：" + v2.hashCode());
        System.out.println(v1.getCreateTime() == v2.getCreateTime());   // false
     }
  }