Java浅拷贝与深拷贝

Java浅拷贝与深拷贝

• Java浅拷贝与深拷贝

转载请标明出处：
https://blog.csdn.net/u011035026/article/details/103269326

1、什么叫Java浅拷贝？

 浅拷贝是会将对象的每个属性进行依次复制，但是当对象的属性值是引用类型时，实质复制的是其引用，当引用指向的值改变时也会跟着变化。

2、什么叫Java深拷贝？

 深拷贝复制变量值，对于引用数据，则递归至基本类型后，再复制。深拷贝后的对象与原来的对象是完全隔离的，互不影响，对一个对象的修改并不会影响另一个对象。

3、Java浅拷贝和深拷贝的区别是什么？

 通俗来讲浅拷贝的复制其引用，当引用指向的值改变时也会跟着变化；而深拷贝则是与原来的对象完全隔离，互补影响。

4、思维导图

5、测试用例分析

• 浅拷贝测试用例

public class ShallowExperience {
    private String skill;

    public void setSkill(String skill) {
        this.skill = skill;
    }

    public void setShallowExperience(String skill) {
        this.skill = skill;
    }

    @Override
    public String toString() {
        return skill;
    }
}

public class ShallowCloneTest implements Cloneable {

    private int age;
    private ShallowExperience shallowExperience;

    public ShallowCloneTest() {
        this.age = 10;
        this.shallowExperience = new ShallowExperience();
    }

    public ShallowExperience getExperience() {
        return shallowExperience;
    }

    public void setShallowExperience(String skill) {
        shallowExperience.setShallowExperience(skill);
    }

    public void show() {
        System.out.println(shallowExperience.toString());
    }

    public int getAge() {
        return age;
    }

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

public class TestMain {

    public static void main(String[] args) throws CloneNotSupportedException {
        System.out.println("======浅拷贝======");
        shallowCloneTest();
    }

    /**
     * 浅拷贝测试用例
     *
     * @throws CloneNotSupportedException
     */
    private static void shallowCloneTest() throws CloneNotSupportedException {
        ShallowCloneTest test = new ShallowCloneTest();
        test.setShallowExperience("我是小明，我精通Java，C++的复制粘贴");
        test.show();
        ShallowCloneTest cloneTest = (ShallowCloneTest) test.clone();
        cloneTest.show();
        cloneTest.setShallowExperience("我是小明的副本，我精通Java,C++");
        cloneTest.show();
        test.show();
        System.out.println(cloneTest.getAge());
    }
}

//运行结果
======浅拷贝======
我是小明，我精通Java，C++的复制粘贴
我是小明，我精通Java，C++的复制粘贴
我是小明的副本，我精通Java,C++
我是小明的副本，我精通Java,C++
10

• 深拷贝测试用例

public class DeepExperience implements Cloneable{
    private String skill;

    public void setSkill(String skill) {
        this.skill = skill;
    }

    public void setDeepExperience(String skill) {
        this.skill = skill;
    }

    @Override
    public String toString() {
        return skill;
    }

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

public class DeepCloneTest implements Cloneable {

    private int age;
    private DeepExperience deepExperience;

    public DeepCloneTest() {
        this.age = 10;
        this.deepExperience = new DeepExperience();
    }

    public DeepExperience getExperience() {
        return deepExperience;
    }

    public void setDeepExperience(String skill) {
        deepExperience.setDeepExperience(skill);
    }

    public void show() {
        System.out.println(deepExperience.toString());
    }

    public int getAge() {
        return age;
    }

    @Override
    protected Object clone() throws CloneNotSupportedException {
        DeepCloneTest deepCloneTest = (DeepCloneTest) super.clone();
        deepCloneTest.deepExperience = (DeepExperience) deepCloneTest.getExperience().clone();
        return deepCloneTest;
    }
}

public class TestMain {

    public static void main(String[] args) throws CloneNotSupportedException {
        System.out.println("======深拷贝======");
        deepCloneTest();
    }

    /**
     * 深拷贝测试用例
     *
     * @throws CloneNotSupportedException
     */
    private static void deepCloneTest() throws CloneNotSupportedException {
        DeepCloneTest test = new DeepCloneTest();
        test.setDeepExperience("我是小明，我精通Java，C++的复制粘贴");
        test.show();
        DeepCloneTest cloneTest = (DeepCloneTest) test.clone();
        cloneTest.show();
        cloneTest.setDeepExperience("我是小明的副本，我精通Java,C++");
        cloneTest.show();
        test.show();
        System.out.println(cloneTest.getAge());
    }
}

//运行结果
======深拷贝======
我是小明，我精通Java，C++的复制粘贴
我是小明，我精通Java，C++的复制粘贴
我是小明的副本，我精通Java,C++
我是小明，我精通Java，C++的复制粘贴
10