浅谈Java设计模式之原型模式知识总结

浅谈Java设计模式之原型模式知识总结

如何使用？

1.首先定义一个User类，它必须实现了Cloneable接口，重写了clone()方法。

public class User implements Cloneable {

private String name;

private int age;

private Brother brother;

@Override

protected Object clone() throws CloneNotSupportedException {

return super.clone();

}

}

2.Brother类

public class Brother{

private String name;

}

3.应用演示类

public class PrototypeDemo {

public static void main(String[] args) throws CloneNotSupportedException {

User user1 = new User();

user1.setName("秋红叶");

user1.setAge(20);

Brother brother1 = new Brother();

brother1.setName("七夜圣君");

user1.setBrother(brother1);

// 我们从克隆对象user2中修改brother，看看是否会影响user1的brother

User user2 = (User) user1.clone();

user2.setName("燕赤霞");

Brother brother2 = user2.getBrother();

brother2.setName("唐钰小宝");

System.out.println(user1);

System.out.println(user2);

System.out.println(user1.getBrother() == user2.getBrother());

}

}

4.深拷贝写法

这是User类

public class User implements Cloneable {

private String name;

private int age;

private Brother brother;

/**

* 主要就是看这个重写的方法，需要将brother也进行clone

*/

@Override

protected Object clone() throws CloneNotSupportedException {

User user = (User) super.clone();

user.brother = (Brother) this.brother.clone();

return user;

}

}

这是Brothhttp://er类

public class Brother implements Cloneable{

private String name;

@Override

protected Object clone() throws CloneNotSupportedException {

return super.clone();

}

}

这里是结果演示

public class PrototypeDemo {

public static void main(String[] args) throws CloneNotSupportedException {

User user1 = new User();

user1.setName("秋红叶");

user1.setAge(20);

Brother brother1 = new Brother();

brother1.setName("七夜圣君");

user1.setBrother(brother1);

// 我们从克隆对象user2中修改brother，看看是否会影响user1的brother

User user2 = (User) user1.clone();

user2.setName("燕赤霞");

Brother brother2 = user2.getBrother();

brother2.setName("唐钰小宝");

System.out.println(user1);

System.out.println(user2);

System.out.println(user1.getBrother() == user2.getBrother());

}

}

可以看到，user1的brother没有受到user2的影响，深拷贝成功！

5.图解深拷贝与浅拷贝

总结与思考

java中object类的clone()方法为浅拷贝必须实现Cloneable接口如果想要实现深拷贝，则需要重写clone()方法

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