Java中对象快速复制的几种方式详解

//浅拷贝
class CloneClass implements Cloneable{ 
　public int a; 
　public Object clone(){ 
　　CloneClass o = null; 
　　try{ 
　　　o = (CloneClass)super.clone(); 
　　}catch(CloneNotSupportedException e){ 
　　　e.printStackTrace(); 
　　} 
　　return o; 
　} 
｝

//深度拷贝
class CloneClass implements Cloneable{ 
　public int a; 
  public Class1 t;
  public CloneClass (int a,Class1 t) {
        this.a = a;
        this.t = t;
  }
　public Object clone(){ 
　　CloneClass o = null; 
　　try{ 
　　　o = (CloneClass)super.clone(); 
      o.test = (Class1)t.clone();
　　}catch(CloneNotSupportedException e){ 
　　　e.printStackTrace(); 
　　} 
　　return o; 
　} 
｝
//Class1 也必须实现Cloneable接口
class Class1 implements Cloneable{ 
    public Object clone(){ 
　　     Class1 o = null; 
　　     try{ 
　　　      o = (Class1 )super.clone(); 
　　     }catch(CloneNotSupportedException e){ 
　　　      e.printStackTrace(); 
　　     } 
　　     return o; 
　} 
}

Person p = new Person();
Person p1 = p.clone();

/*
 * 为克隆使用序列化，
 * 直接将对象序列化到输出流中，然后将其读回，这样产生的新对象是对现有对象的一个深拷贝
 * 在此过程中，不必将对象写出到文件，可以用ByteArrayOutPutStream将数据保存到字节数组中
 * 
 * 这个方法很灵巧，它通常会比显示地构建新对象并复制或克隆数据域的克隆方法慢得多
 */
public class SerialCloneTest
{  
   public static void main(String[] args)
   {  
      Employee harry = new Employee("Harry Hacker", 35000);
      // clone harry
      Employee harry2 = (Employee) harry.clone();
      System.out.println(harry==harry2);
      System.out.println(harry);
      System.out.println(harry2);
   }
}
/**
   A class whose clone method uses serialization.
*/
class SerialCloneable implements Cloneable, Serializable
{ 
	private static final long serialVersionUID = 1L;
	//深拷贝
   public Object clone()
   {  
      try
      {  
         // save the object to a byte array
    	 //将该对象序列化成流,因为写在流里的是对象的一个拷贝，而原对象仍然存在于JVM里面
         ByteArrayOutputStream bout = new ByteArrayOutputStream();
         ObjectOutputStream out = new ObjectOutputStream(bout);
         out.writeObject(this);
         out.close();
         // read a clone of the object from the byte array
         ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
         ObjectInputStream in = new ObjectInputStream(bin);
         Object ret = in.readObject();
         in.close();
         return ret;
      }  
      catch (Exception e)
      {  
         return null;
      }
   }
}
/**
   The familiar Employee class, redefined to extend the
   SerialCloneable class. 
*/
class Employee extends SerialCloneable
{  
	private static final long serialVersionUID = 1L;
    private String name;
    private double salary;
   public Employee(String n, double s)
   {  
      name = n;
      salary = s;
   }
   public String getName()
   {  
      return name;
   }
   public double getSalary()
   {  
      return salary;
   }
   public String toString()
   {  
      return getClass().getName()
         + "[name=" + name
         + ",salary=" + salary
         + "]";
   }
}

public class Person {
    private String name;
    private String sex;
    private int age;
    private Date birthday;
    private Dog dog;
    public Dog getDog() {
        return dog;
    }
    public void setDog(Dog dog) {
        this.dog = dog;
    }
    private Double high;
    public String getName() {
        return name;
    }
    public Double getHigh() {
        return high;
    }
    public void setHigh(Double high) {
        this.high = high;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                ", birthday=" + birthday +
                ", dog=" + dog +
                ", high=" + high +
                '}';
    }
}

public class Dog {
    public String dogName;
    public String getDogName() {
        return dogName;
    }
    public void setDogName(String dogName) {
        this.dogName = dogName;
    }
    @Override
    public String toString() {
        return "Dog{" +
                "dogName='" + dogName + '\'' +
                '}';
    }
}

import org.apache.commons.beanutils.BeanUtils;
import java.lang.reflect.InvocationTargetException;
import java.util.Date;
public class BeanUtilTest {
    public static void main(String[] args) {
        Person per = new Person();
        Person per1 = new Person();
        per.setName("zhangsan");
        per.setSex("男");
        per.setAge(20);
        per.setBirthday(new Date());
        Dog dog = new Dog();
        dog.setDogName("1111111111111111");
        per.setDog(dog);
        try {
            BeanUtils.copyProperties(per1, per);
            Dog dog1 = per.getDog();
            dog1.setDogName("2222222222222222");
            per.setName("666666666666");
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        System.out.println(per.toString());
        System.out.println(per1.toString());
    }
}