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java学习---对象的克隆和序列化
1、假clone,虚拟机只是将对象的内存地址clone了一份,修改克隆后的对象内容,将影响原对象
public class Employee{ public Employee(){ } public Employee(String name, int age){ this.age = age; this.name = name; } @Override public String toString(){ return "姓名: " + name + "年龄: " + age; } public String getName(){ return name; } public void setName(String name){ this.name = name; } public int getAge(){ return age; } public void setAge(int age){ this.age = age; } public static void main(String[] args){ Employee demo1 = new Employee("rollen", 20); System.out.println(demo1); Employee demo2 = demo1; demo2.setAge(100); demo2.setName("hello world"); System.out.println(demo1); System.out.println(demo2); } private String name; private int age; }运行结果:
【运行结果】
姓名: rollen年龄: 20
姓名: hello world年龄: 100
姓名: hello world年龄: 100
============================================================================================2、含有基本数据类型的对象的克隆,必须实现clone方法。克隆后对象属性的修改将不影响原对象的属性
class Address{ public Address(){ } public Address(String state, int number){ this.number = number; this.state = state; } @Override public String toString(){ return "state: " + state + " munber: " + number; } public String getState(){ return state; } public void setState(String state){ this.state = state; } public int getNumber(){ return number; } public void setNumber(int number){ this.number = number; } private String state; private int number; } public class Employee implements Cloneable{ public Employee(){ } public Employee(String name, int age, Address address){ this.address = address; this.age = age; this.name = name; } public String getName(){ return name; } public void setName(String name){ this.name = name; } public int getAge(){ return age; } public void setAge(int age){ this.age = age; } public Address getAddress(){ return address; } public void setAddress(Address address){ this.address = address; } @Override public String toString(){ StringBuilder sb = new StringBuilder(); sb.append("name:" + name + ", "); sb.append("age:" + age + " \n"); sb.append("Address: " + address); return sb.toString(); } @Override protected Employee clone(){ Employee employee = null; try{ employee = (Employee) super.clone(); }catch(CloneNotSupportedException e){ e.printStackTrace(); } return employee; } public static void main(String[] args){ System.out.println("克隆之前:"); Address add1 = new Address("中国", 1); Employee emp1 = new Employee("rollen", 20, add1); System.out.println(emp1); System.out.println("克隆之后"); Employee emp2 = emp1.clone(); emp2.setName("hello world"); emp2.setAge(100); emp2.address.setNumber(2); emp2.address.setState("美国"); System.out.println(emp1); System.out.println("-----"); System.out.println(emp2); } private String name; private int age; private Address address; }
【运行结果】:
克隆之前:
name:rollen, age:20
Address: state: 中国 munber: 1
克隆之后
name:rollen, age:20
Address: state: 美国 munber: 2
-----
name:hello world, age:100
Address: state: 美国 munber: 2
==============================================================================================3、含有复制数据结构类的类的克隆,对类中复杂的数据类型也必须实现clone方法。
class Address implements Cloneable{ public Address(){ } public Address(String state, int number){ this.number = number; this.state = state; } @Override public String toString(){ return "state: " + state + " munber: " + number; } @Override protected Address clone() throws CloneNotSupportedException{ Address address = null; address = (Address) super.clone(); return address; } public String getState(){ return state; } public void setState(String state){ this.state = state; } public int getNumber(){ return number; } public void setNumber(int number){ this.number = number; } private String state; private int number; } public class Employee implements Cloneable{ public Employee(){ } public Employee(String name, int age, Address address){ this.address = address; this.age = age; this.name = name; } public String getName(){ return name; } public void setName(String name){ this.name = name; } public int getAge(){ return age; } public void setAge(int age){ this.age = age; } public Address getAddress(){ return address; } public void setAddress(Address address){ this.address = address; } @Override public String toString(){ StringBuilder sb = new StringBuilder(); sb.append("name:" + name + ", "); sb.append("age:" + age + " \n"); sb.append("Address: " + address); return sb.toString(); } @Override protected Employee clone(){ Employee employee = null; try{ employee = (Employee) super.clone(); employee.address = address.clone(); }catch(CloneNotSupportedException e){ e.printStackTrace(); } return employee; } public static void main(String[] args){ System.out.println("克隆之前:"); Address add1 = new Address("中国", 1); Employee emp1 = new Employee("rollen", 20, add1); System.out.println(emp1); System.out.println("克隆之后"); Employee emp2 = emp1.clone(); emp2.setName("hello world"); emp2.setAge(100); emp2.setAddress(new Address("美国", 2)); System.out.println(emp1); System.out.println("-----"); System.out.println(emp2); } private String name; private int age; private Address address; }
【运行结果】:
克隆之前:
name:rollen, age:20
Address: state: 中国 munber: 1
克隆之后
name:rollen, age:20
Address: state: 中国 munber: 1
-----
name:hello world, age:100
Address: state: 美国 munber: 2
=========================================================================================4、序列化接口和对象克隆
import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.Serializable; class Address implements Serializable{ public Address(){ } public Address(String state, int number){ this.number = number; this.state = state; } @Override public String toString(){ StringBuilder sb = new StringBuilder(); sb.append("number: " + number); sb.append("state" + state + "\n"); return sb.toString(); } public String getState(){ return state; } public void setState(String state){ this.state = state; } public int getNumber(){ return number; } public void setNumber(int number){ this.number = number; } private String state; private int number; } public class Employee implements Cloneable, Serializable{ public Employee(){ } public Employee(String name, int age, Address address){ this.address = address; this.age = age; this.name = name; } public String getName(){ return name; } public void setName(String name){ this.name = name; } public int getAge(){ return age; } public void setAge(int age){ this.age = age; } public Address getAddress(){ return address; } public void setAddress(Address address){ this.address = address; } @Override public String toString(){ StringBuilder sb = new StringBuilder(); sb.append("name:" + name + ", "); sb.append("age:" + age + " \n"); sb.append("Address: " + address); return sb.toString(); } @Override protected Employee clone(){ Employee employee = null; ByteArrayOutputStream baos = new ByteArrayOutputStream(); try{ ObjectOutputStream oos = new ObjectOutputStream(baos); oos.writeObject(this); oos.close(); ByteArrayInputStream bais = new ByteArrayInputStream( baos.toByteArray()); ObjectInputStream ois = new ObjectInputStream(bais); employee = (Employee) ois.readObject(); ois.close(); }catch(Exception e){ e.printStackTrace(); } return employee; } public static void main(String[] args){ System.out.println("克隆之前:"); Address add1 = new Address("中国", 1); Employee emp1 = new Employee("rollen", 20, add1); System.out.println(emp1); System.out.println("克隆之后"); Employee emp2 = emp1.clone(); emp2.setName("hello world"); emp2.setAge(100); emp2.address.setNumber(2); emp2.address.setState("美国"); System.out.println(emp1); System.out.println("-----"); System.out.println(emp2); } private String name; private int age; private Address address; }
克隆之前:
name:rollen, age:20
Address: number: 1state中国
克隆之后
name:rollen, age:20
Address: number: 1state中国
-----
name:hello world, age:100
Address: number: 2state美国