Java淺拷貝與深拷貝

Java淺拷貝與深拷貝

• Java淺拷貝與深拷貝

轉載請標明出處：
https://blog.csdn.net/u011035026/article/details/103269326

1、什麼叫Java淺拷貝？

 淺拷貝是會將對象的每個屬性進行依次複製，但是當對象的屬性值是引用類型時，實質複製的是其引用，當引用指向的值改變時也會跟着變化。

2、什麼叫Java深拷貝？

 深拷貝複製變量值，對於引用數據，則遞歸至基本類型後，再複製。深拷貝後的對象與原來的對象是完全隔離的，互不影響，對一個對象的修改並不會影響另一個對象。

3、Java淺拷貝和深拷貝的區別是什麼？

 通俗來講淺拷貝的複製其引用，當引用指向的值改變時也會跟着變化；而深拷貝則是與原來的對象完全隔離，互補影響。

4、思維導圖

5、測試用例分析

• 淺拷貝測試用例

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("======淺拷貝======");
        shallowCloneTest();
    }

    /**
     * 淺拷貝測試用例
     *
     * @throws CloneNotSupportedException
     */
    private static void shallowCloneTest() throws CloneNotSupportedException {
        ShallowCloneTest test = new ShallowCloneTest();
        test.setShallowExperience("我是小明，我精通Java，C++的複製粘貼");
        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());
    }
}

//運行結果
======淺拷貝======
我是小明，我精通Java，C++的複製粘貼
我是小明，我精通Java，C++的複製粘貼
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

• 深拷貝測試用例

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("======深拷貝======");
        deepCloneTest();
    }

    /**
     * 深拷貝測試用例
     *
     * @throws CloneNotSupportedException
     */
    private static void deepCloneTest() throws CloneNotSupportedException {
        DeepCloneTest test = new DeepCloneTest();
        test.setDeepExperience("我是小明，我精通Java，C++的複製粘貼");
        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());
    }
}

//運行結果
======深拷貝======
我是小明，我精通Java，C++的複製粘貼
我是小明，我精通Java，C++的複製粘貼
我是小明的副本，我精通Java,C++
我是小明，我精通Java，C++的複製粘貼
10