Java基礎 深拷貝淺拷貝

Java基礎 深拷貝淺拷貝

• 非基本數據類型 需要new新空間

class Student implements Cloneable{private int id;private String name;private Vector course;public Student(){try{Thread.sleep(1000);System.out.println("Student Constructor called.");}catch (InterruptedException e){e.printStackTrace();}}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getId() {return id;}public void setId(int id) {this.id = id;}public Vector getCourse() {return course;}public void setCourse(Vector course) {this.course = course;}//淺拷貝public Student newInstance(){try{return (Student)this.clone();}catch (CloneNotSupportedException e){e.printStackTrace();}return null;}//深拷貝public Student deepClone(){try{Student cloning = (Student) super.clone();cloning.course = new Vector();return cloning;}catch (CloneNotSupportedException e){e.printStackTrace();}return null;}}public Object clone(){      //覆寫clone()，深拷貝  try{  Student cloning = (Student) super.clone(); // 這里不能使用Student cloning = (Student) this.clone()的原因:正在覆寫本類的clone()方法，如果再調用本類的函數，即：this.clone()，就相當于無限遞歸無限死循環了，最終會崩潰的。所以這里：super.clone()。cloning.courses = new Vector();     //關鍵點：非基本數據類型的空間需要自己新開辟一塊兒  return cloning;  }catch(CloneNotSupportedException e){  e.printStackTrace();  }  return null;  
}  

參考資料

謹慎覆蓋clone
Java中的clone() 深拷貝 淺拷貝