[toc]
引用拷贝和对象拷贝
@AllArgsConstructor
@Data
class User implements Cloneable {
private String name;
private int age;
@Override
protected Object clone() throws CloneNotSupportedException {
return super.clone();
}
}
/**
* 引用拷贝和对象拷贝
*/
@Test
public void referenceCopyAndObjectCopy() throws CloneNotSupportedException {
User user = new User("tom", 10);
//引用拷贝
User user1 = user;
//输出的hashCode一致，说明是一个对象
//cn.zerohy.bug.sample.DeepCopyAndShallowCopyTest$1User@184f6be2
//cn.zerohy.bug.sample.DeepCopyAndShallowCopyTest$1User@184f6be2
System.out.println(user);
System.out.println(user1);
//对象拷贝
User user2 = (User) user.clone();
//新对象
//cn.zerohy.bug.sample.DeepCopyAndShallowCopyTest$1User@184f6be2
//cn.zerohy.bug.sample.DeepCopyAndShallowCopyTest$1User@56aac163
System.out.println(user);
System.out.println(user2);
}
浅拷贝
@Data
@ToString(callSuper = true)
@AllArgsConstructor
class Room implements Cloneable {
private User user;
private int id;
private String roomName;
@Override
protected Object clone() throws CloneNotSupportedException {
return super.clone();
}
}
/**
* 浅拷贝
*/
@Test
public void shallowCopy() throws CloneNotSupportedException {
User user = new User("Jone", 12);
Room room = new Room(user, 1001, "蓬莱阁");
Room clone = (Room) room.clone();
//(User(name=Jone, age=12), id=1001, roomName=蓬莱阁)
System.out.println(room);
System.out.println(clone);
clone.setId(200);
clone.setRoomName("岳阳楼");
clone.getUser().setAge(50);
clone.getUser().setName("Mike");
//改变clone对象中的user属性,原对象中的user属性也改变了，说明克隆时user属性是引用拷贝
//(User(name=Mike, age=50), id=1001, roomName=蓬莱阁)
//(User(name=Mike, age=50), id=200, roomName=岳阳楼)
System.out.println(room);
System.out.println(clone);
}
深拷贝
/**
* 深拷贝
*/
@Test
public void deepCopy() {
/**
* 深拷贝有多种方式：
* 1、重写clone方法，有缺陷，对于引用类型里面还包含很多引用类型，或者内层引用类型的类里面又包含引用类型，使用clone方法就会很麻烦
* 2、通过序列化和反序列化的方式，如先将room实例序列化成json，再将json数据反序列化成room对象
*/
}