Java深度复制功能与用法实例分析

package com.yo.java;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.io.Serializable;import java.util.ArrayList;import java.util.List;/** * Java 实现深度复制 * @author Yo * */public class DeepCopy implements Serializable{  int i;  /**   * @param args   * @throws IOException   * @throws ClassNotFoundException   */  public static void main(String[] args) throws ClassNotFoundException, IOException {    demo1();    demo2();  }  /**   * 深度复制，实参类必须实现Serializable接口   * @param o   * @return   * @throws IOException   * @throws ClassNotFoundException   */  public static Object deepCopy(Object o) throws IOException, ClassNotFoundException {//   //先序列化，写入到流里    ByteArrayOutputStream bo = new ByteArrayOutputStream();    ObjectOutputStream oo = new ObjectOutputStream(bo);    oo.writeObject(o);    //然后反序列化，从流里读取出来，即完成复制    ByteArrayInputStream bi = new ByteArrayInputStream(bo.toByteArray());    ObjectInputStream oi = new ObjectInputStream(bi);    return oi.readObject();  }  /**   * 引用传递与深度复制   * @throws ClassNotFoundException   * @throws IOException   */  public static void demo1() throws ClassNotFoundException, IOException {    System.out.println("===========未使用深度复制=========");    DeepCopy dc1 = new DeepCopy();    dc1.i = 1;//初始化dc1里i的值    DeepCopy dc2 = dc1;    dc1.i = 2;//改变dc1里i的值    System.out.println("dc1 : " + dc1.i);    System.out.println("dc2(引用传递) : " + dc2.i);    System.out.println("===========使用深度复制=========");    DeepCopy dc3 = new DeepCopy();    dc3.i = 1;//初始化dc3里i的值    DeepCopy dc4 = (DeepCopy)deepCopy(dc3);    dc3.i = 2;//改变dc3里i的值    System.out.println("dc3 : " + dc3.i);    System.out.println("dc4(深度复制) : " + dc4.i);  }  /**   * 集合的值复制与深度复制   * @throws ClassNotFoundException   * @throws IOException   */  public static void demo2() throws ClassNotFoundException, IOException {    System.out.println("===========未使用深度复制=========");    //创建DeepCopy对象，并初始化i的值，添加到list1集合    DeepCopy dc = new DeepCopy();    dc.i = 1;//初始化dc1里i的值    List<DeepCopy> list1 = new ArrayList<DeepCopy>();    list1.add(dc);    //未使用深度复制    List<DeepCopy> list2 = new ArrayList<DeepCopy>(list1);//这里与使用Collections.copy(dest, src)结果一样    //改变list1中元素的值    for(DeepCopy d1 : list1) {      //改变dc1里i的值      d1.i = 2;    }    //遍历list    for(DeepCopy d1 : list1) {      System.out.println("list1 : " + d1.i);    }    //遍历list2    for(DeepCopy d2 : list2) {      System.out.println("list2(复制） : " + d2.i);    }    System.out.println("===========使用深度复制后=========");    DeepCopy dc3 = new DeepCopy();    dc3.i = 1;//初始化dc3里i的值    List<DeepCopy> list3 = new ArrayList<DeepCopy>();    list3.add(dc3);    List<DeepCopy> list4 = (List<DeepCopy>) deepCopy(list3);    for(DeepCopy d : list3) {      //改变dc3里i的值      d.i = 2;    }    for(DeepCopy d3 : list3) {      System.out.println("list3 : " + d3.i);    }    for(DeepCopy d4 : list4) {      System.out.println("list4(深度复制）: " + d4.i);    }  }}

===========未使用深度复制=========dc1 : 2dc2(引用传递) : 2===========使用深度复制=========dc3 : 2dc4(深度复制) : 1===========未使用深度复制=========list1 : 2list2(复制） : 2===========使用深度复制后=========list3 : 2list4(深度复制）: 1