java设计模式之原型模式

本篇来说一说java设计模式之原型模式。

本篇也是创建者模式的最后一篇了。也是看起来最简单的一篇。就一句话！就是一个作业抄起来太复杂了，即使给你别人写好的照着抄也不想写一遍！那怎么办？复印啊！很简单嘛。

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package top.txiner.prototype;

public class Homework implements Cloneable{


    private String title;
    private String content;


    public Homework() {

    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }


    @Override
    public String toString() {
        return "Homework{" +
                "title='" + title + '\'' +
                ", content='" + content + '\'' +
                '}';
    }


    @Override
    protected Homework clone() throws CloneNotSupportedException {
        return (Homework)super.clone();
    }

}

看，连复印这个机器java都给创建好了，直接写clone方法就好了。当然了，你不implements Clonable接口也可以，因为是默认继承Object的。直接在作业里面抄上去！

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package top.txiner.prototype;

public class Client {
    public static void main(String[] args) throws CloneNotSupportedException {
        Homework xiaomingChinese=new Homework();
        xiaomingChinese.setTitle("Chinese homework");
        xiaomingChinese.setContent("I love nature");
        Homework xiaogangChinese=xiaomingChinese.clone();
        System.out.println(xiaogangChinese);
        System.out.println(xiaomingChinese);
    }
}

完美！后来，小明不干了，凭什么我千辛万苦写的作业要给你啊！我要加自己的信息，网作业里面标记上我的名字。于是，作业变成了

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package top.txiner.prototype;

public class Homework implements Cloneable{


    private String title;
    private String content;
    private User writer;

    public Homework() {
        writer=new User();
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }



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


    public User getWriter() {
        return writer;
    }

    @Override
    public String toString() {
        return "Homework{" +
                "title='" + title + '\'' +
                ", content='" + content + '\'' +
                ", writer=" + writer +
                '}';
    }


    @Override
    protected Homework clone() throws CloneNotSupportedException {
        return (Homework)super.clone();
    }

}
public class User {
    private String name;

    public User() {
    }

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                '}';
    }
}

小刚还想抄

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public class Client {
    public static void main(String[] args) throws CloneNotSupportedException {
        Homework xiaomingChinese=new Homework();
        xiaomingChinese.setTitle("Chinese homework");
        xiaomingChinese.setContent("I love nature");
        xiaomingChinese.setWriter("xiaoMing");
        Homework xiaogangChinese=xiaomingChinese.clone();
        xiaogangChinese.setWriter("xiaoGang");
        System.out.println(xiaogangChinese);
        System.out.println(xiaomingChinese);
    }
}

一看，不好，这下虽然设置了自己的名字，但是在复印的时候还会覆盖前面的东西！（引用的对象--用户是同一个）赶快找补救办法！有了！深拷贝！我在复印的时候注意点，遇到这种信息改好了再复印！于是乎

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    public Homework deepCLone(){
        Homework copy=new Homework();
        copy.setTitle(this.title);
        copy.setContent(this.content);
        copy.setWriter(this.writer.getName());
        return copy;
    }

恩，很不错，是自己的信息了！可是这样太针对了！必须得知道引用的对象，然后再重新构造，好麻烦的！有的时候，只需要一个新的对象，里面并不一定含有个人的信息，那好办啊！直接序列化称流，然后再读出来就好啦！

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        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(bos);
        oos.writeObject(this);
        ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
        ObjectInputStream ois = new ObjectInputStream(bis);
        return ois.readObject();

这样以后抄作业，不，开发项目就简单多了！

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