JAVA中浅复制与深复制

时间:2007-03-25 20:47:35 来源: 作者: 点击:次出处:技术无忧

关键字：复制克隆代码

class Professor
{
    String name;
    int age;
    Professor(String name,int age)
    {
        this.name=name;
        this.age=age;
    }
}
class Student implements Cloneable
{
    String name;//常量对象。
    int age;
    Professor p;//学生1和学生2的引用值都是一样的。
    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();
        }
        catch(CloneNotSupportedException e)
        {
            System.out.println(e.toString());
        }
        o.p=(Professor)p.clone();
        return o;
    }
}
public static void main(String[] args)
    {
      Professor p=new Professor("wangwu",50);
      Student s1=new Student("zhangsan",18,p);
      Student s2=(Student)s1.clone();
      s2.p.name="lisi";
     s2.p.age=30;
System.out.println("name="+s1.p.name+","+"age="+s1.p.age);//学生1的教授

ONT color=#000000>                                                                                                                //成为lisi,age为30。
}
那应该如何实现深层次的克隆，即修改s2的教授不会影响s1的教授？代码改进如下。

改进使学生1的Professor不改变（深层次的克隆）
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();
        }
        catch(CloneNotSupportedException e)
        {
            System.out.println(e.toString());
        }
        o.p=(Professor)p.clone();
        return o;
    }
}
public static void main(String[] args)
    {
      Professor p=new Professor("wangwu",50);
      Student s1=new Student("zhangsan",18,p);
      Student s2=(Student)s1.clone();
      s2.p.name="lisi";
     s2.p.age=30;
System.out.println("name="+s1.p.name+","+"age="+s1.p.age);//学生1的教授不改变。有关操作系统的更多文章请进：技术无忧