浅拷贝与深拷贝

来源：互联网发布：双立人珐琅铸铁锅知乎编辑：程序博客网时间：2024/06/09 22:24

浅拷贝与深拷贝，就是地址之间的“捆绑”，而且它涉及到栈内存和堆内存的储存关系；还是用代码和简图来说明问题吧！

public class Client {

public static void main(String[] rags ) {

MyDate d = new MyDate(1995,4,22);

Person p = new Person("Jack",d);

System.out.println("P:"+p.toString()) //Jack,1995年4月22日

Person p3=new Person(p); //引用赋值必“捆绑”，即地址之间“赋值”

p.setName("Tom");

p.getBirth().setYear(2000);

System.out.println("P:"+p.toString()) //Tom,2000年4月22日

System.out.println("P3:"+p.toString()) //Jack,2000年4月22日

}

public class MyDate {

private int year;

private int month;

private int day;

        public MyDate(int year,int month,int day) {
            this.year=year;
            this.month=month;
           this.day=day;
       }

        public MyDate() {
           this(1970,1,1);
       }

public MyDate (MyDate d) {

this(d.year,d.month,d.day);

}

       public void setYear(int year) {
           this.year = year;
       }
       public String toString(){
            return year+"年"+month+"月"+day+"日";
        }
}

  public class Person {
         private String name;
          private MyDate birth;

         public Person(String name,MyDate birth){
           this.name = name;
         //this.birth = birth;//引用赋值必捆绑----出现浅拷贝

       //深拷贝的本质就是把"引用赋值" 变成 "基本数据类型或String类型赋值"
         this.birth = new MyDate(birth);
        }

        public Person(){
          this("NoName",null);
      }
       public Person( Person p ){
          this(p.name, p.birth);
     }

        public void setName(String name){
           this.name = name;
       }
       public MyDate getBirth(){
           return birth;
       }
       public String toString(){
           return name+","+birth.toString();
    }

}

拷贝分析图：

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