java克隆-深拷贝与浅拷贝_addall是深拷贝还是浅拷贝-优快云博客

博客主要介绍了Java中的浅克隆和深克隆。浅克隆和深克隆是Java克隆机制的重要内容，对于理解对象复制和数据处理有重要意义。

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浅克隆：

class Student   implements Cloneable{
    public String sname;
    public Date birthday;
    public Student() {}
    public Student(String sname, Date birthday) {
        //super();
        this.sname = sname;
        this.birthday = birthday;
    }

    public String getSname() {
        return sname;
    }
    public void setSname(String sname) {
        this.sname = sname;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    @Override
    protected Object clone() throws CloneNotSupportedException {
        Object obj= super.clone();
        return obj;
    }
}

        Student s1=new Student("link",new Date(123456));        
        System.out.println(s1);
        //克隆的对象:值为原来的值
        //属性为浅复制，即指向相同的属性值，其值未做拷贝
        Student s2=(Student) s1.clone();
        System.out.println(s2);
        System.out.println(s1.sname==s2.sname);//true
        System.out.println(s1.birthday==s2.birthday);//true

深克隆：

class Student   implements Cloneable{
    public String sname;
    public Date birthday;
    public Student() {}
    public Student(String sname, Date birthday) {
        //super();
        this.sname = sname;
        this.birthday = birthday;
    }

    public String getSname() {
        return sname;
    }
    public void setSname(String sname) {
        this.sname = sname;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    @Override
    protected Object clone() throws CloneNotSupportedException {
        Object obj= super.clone();
        Student s=(Student) obj;
        s.sname=new String(this.getSname());
        s.birthday=(Date) this.birthday.clone();    
        return obj;
    }
}


        Student s1=new Student("link",new Date(123456));        
        System.out.println(s1);
        Student s2=(Student) s1.clone();
        System.out.println(s2);
        System.out.println(s1.sname==s2.sname);//false
        System.out.println(s1.birthday==s2.birthday);//false