對象克隆指的就是對象的復制操作,在Object類里面提供一個專門的克隆方法: ~~~ protected native Object clone() throws CloneNotSupportedException; ~~~ 注意權限,外部要克隆,可以覆寫這個方法 此方法上會拋出一個異常CloneNotSupportedException,克隆不支持 **如果要使用對象克隆的類沒有實現Cloneable接口,就會拋出此異常** 我們看下Cloneable接口源碼,發現他里面沒有方法,是標識接口 **注意克隆出來的是新的接口** ~~~ package com.study; //此類的對象可以克隆 class Book implements Cloneable { private String title; private double price; public Book(String title, double price) { this.title = title; this.price = price; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public double getPrice() { return price; } public void setPrice(double price) { this.price = price; } //原本的權限是protected //此類需要對象克隆操作,所有才需要進行方法的覆寫 @Override protected Object clone() throws CloneNotSupportedException { return super.clone(); } @Override public String toString() { final StringBuilder sb = new StringBuilder("{"); sb.append("\"title\":\"") .append(title).append('\"'); sb.append(",\"price\":") .append(price); sb.append('}'); return sb.toString(); } } public class HelloWorld { public static void main(String[] args) throws CloneNotSupportedException { Book java = new Book("java", 80); //克隆出來的是個新對象 Object clone = java.clone(); java.setPrice(100); System.out.println(clone); } } ~~~