原型模式

原型模式就是通过原型创建多个对象，简单来说就是通过一个对象去复制多个对象
类图如下

原型模式类图

需要实现Cloneable接口，复写clone()方法
具体代码如下

public class Mail implements Cloneable{
    private String receiver;
    private String subject;
    private String appellation;
    private String context;
    private String tail;

    public Mail(AdvTemplate advTemplate){
        this.context = advTemplate.advContext();
        this.subject = advTemplate.getAdvSubject();
    }

    public String getReceiver() {
        return receiver;
    }

    public void setReceiver(String receiver) {
        this.receiver = receiver;
    }

    public String getSubject() {
        return subject;
    }

    public void setSubject(String subject) {
        this.subject = subject;
    }

    public String getAppellation() {
        return appellation;
    }

    public void setAppellation(String appellation) {
        this.appellation = appellation;
    }

    public String getContext() {
        return context;
    }

    public void setContext(String context) {
        this.context = context;
    }

    public String getTail() {
        return tail;
    }

    public void setTail(String tail) {
        this.tail = tail;
    }

    @Override
    protected Mail clone(){
        Mail mail = null;
        try {
            mail = (Mail)super.clone();
        }catch (CloneNotSupportedException e){

        }
        return mail;
    }
}

我们在调用是可 mail.clone();用于复制对象，直接重堆中复制对象，不会调用类的构造函数
这里需要注意浅拷贝和深拷贝
浅拷贝：我们在进程clone时只会拷贝基本数据类型不会拷贝引用数据类型和内部数组，如果需要拷贝要对私有对象进行独立拷贝（深拷贝）

 @Override
    protected Mail clone(){
        Mail mail = null;
        try {
            mail = (Mail)super.clone();
            this.list = (ArrayList<String>)this.list.clone();
        }catch (CloneNotSupportedException e){

        }
        return mail;
    }

如果需要拷贝那不能使用final来修饰