Java 深浅拷贝

Posted 2020-08-02 邗影

2016-07-02

1深拷贝：不仅拷贝对象，而且对象所引用地址的内容一块拷贝。改变一个对象的某个属性，并不影响另一个对象所引用的内容。

2浅拷贝：仅拷贝对象本身，并不对所引用（所指的）内容进行拷贝，当对一个对象做改变的时候，另一个对象的相应属性也做同样的改变。

3深拷贝要重写clone函数。implements Cloneable。

浅拷贝：

 深拷贝

这个代码是借鉴的（记得是这样的，标注---借鉴资源）

class Professor0 implements Cloneable {
    String name;
    int age;
 
    Professor0(String name, int age) {
        this.name = name;
        this.age = age;
    }
 
    public Object clone() throws CloneNotSupportedException {
        return super.clone();//调用父类的
    }
}
 
class Student0 implements Cloneable {
    String name;// 常量对象。
    int age;
    Professor0 p;// 学生1和学生2的引用值都是一样的。
 
    Student0(String name, int age, Professor0 p) {
        this.name = name;
        this.age = age;
        this.p = p;
    }
 
  /* public Object clone() {
        Student0 o = null;
        try {
            o = (Student0) super.clone();
        } catch (CloneNotSupportedException e) {
            System.out.println(e.toString());
        }
 
        return o;
    }*/
}
 
public class qiancopy {
    public static void main(String[] args) {
        Professor0 p = new Professor0("perfesser0", 50);
        Student0 s1 = new Student0("stu1", 18, p);
        System.out.println("学生s1的姓名：" + s1.name + "\\n学生s1教授的姓名：" + s1.p.name + "," + "\\n学生s1教授的年纪" + s1.p.age+"......end");// 学生1的教授
    
        Student0 s2 =s1;
        s2.p.name = "s2copys";
        s2.p.age = 30;
        s2.name = "s2";
        s2.age = 45;
        System.out.println("学生s1的姓名：" + s1.name+ "\\n学生s1的年龄：" + s1.age + "\\n学生s1教授的姓名：" + s1.p.name + "," + "\\n学生s1教授的年纪" + s1.p.age+"...end");
        System.out.println("学生s2的姓名：" + s2.name+ "\\n学生s2的年龄：" + s2.age + "\\n学生s2教授的姓名：" + s2.p.name + "," + "\\n学生s2教授的年纪" + s2.p.age+"...end");// 学生1的教授
    
    }
}

class Professor implements Cloneable {
    String name;
    int age;
 
    Professor(String name, int age) {
        this.name = name;
        this.age = age;
    }
 
    public Object clone() {
        Object o = null;
        try {
            o = super.clone();
        } catch (CloneNotSupportedException e) {
            System.out.println(e.toString());
        }
        return o;
    }
}
 
class Student implements Cloneable {
    String name;
    int age;
    Professor p;
 
    Student(String name, int age, Professor p) {
        this.name = name;
        this.age = age;
        this.p = p;
    }
 
    public Object clone() {
        Student o = null;
        try {
            o = (Student) super.clone();//stu 深拷贝
        } catch (CloneNotSupportedException e) {
            System.out.println(e.toString());
        }
        o.p = (Professor) p.clone();//professer深拷贝
        return o;
    }
}
 
public class shencopy {
    public static void main(String args[]) {
        
        Professor p = new Professor("professer1", 50);
        Student s1 = new Student("stu1", 18, p);
        System.out.println("学生s1的姓名：" + s1.name+ "\\n学生s1的年龄：" + s1.age + "\\n学生s1教授的姓名：" + s1.p.name + "," + "\\n学生s1教授的年纪" + s1.p.age+"......end");// 学生1的教授
        
        Student s2 = (Student) s1.clone();
        s2.name = "s2copys";
        s2.age = 30;
        s2.p.name = "stu2";
        s2.p.age = 30;
        System.out.println("学生s1的姓名：" + s1.name+ "\\n学生s1的年龄：" + s1.age + "\\n学生s1教授的姓名：" + s1.p.name + "," + "\\n学生s1教授的年纪" + s1.p.age+"......end");// 学生1的教授
        System.out.println("学生s2的姓名：" + s2.name+ "\\n学生s2的年龄：" + s2.age + "\\n学生s2教授的姓名：" + s2.p.name + "," + "\\n学生s2教授的年纪" + s2.p.age+"......end");// 学生2的教授
        
    }
}