user.java

这是孙卫琴在"Java与面向对象编程"一书的源代码。

package safe;
import java.io.*;
public class User implements Serializable {
  private String name;
  private transient String password;
  public User(String name, String password) {
    this.name=name;
    this.password=password;
  }
  public String toString() {
    return name + " " + password;
  }
  
  /** 加密数组，将buff数组中的每个字节的每一位取反 
   *  例如13的二进制为00001101，取反后为11110010
   */
  private byte[] change(byte[] buff){
    for(int i=0;i<buff.length;i++){
      int b=0;
      for(int j=0;j<8;j++){
        int bit=(buff[i]>>j & 1)==0 ? 1:0;
        b+=(1<<j)*bit;
      }
      buff[i]=(byte)b;
    }
    return buff;
  }

  private void writeObject(ObjectOutputStream stream)throws IOException {
    stream.defaultWriteObject();  //先按默认方式序列化 
    stream.writeObject(change(password.getBytes()));
  }
  private void readObject(ObjectInputStream stream)
          throws IOException, ClassNotFoundException {
    stream.defaultReadObject();  //先按默认方式反序列化
    byte[] buff=(byte[])stream.readObject();
    password = new String(change(buff));
  }
  public static void main(String[] args) throws Exception{
    User user = new User("Tom", "123456");
    System.out.println("Before Serialization:" + user);
    ByteArrayOutputStream buf = new ByteArrayOutputStream();
   
    //把User对象序列化到一个字节缓存中
    ObjectOutputStream o =new ObjectOutputStream(buf);
    o.writeObject(user);
      
    //从字节缓存中反序列化User对象
    ObjectInputStream in =new ObjectInputStream(
          new ByteArrayInputStream(buf.toByteArray()));
    user= (User)in.readObject();
    System.out.println("After Serialization:" + user);
   }
}



/****************************************************
 * 作者：孙卫琴                                     *
 * 来源：<<Java面向对象编程>>                       *
 * 技术支持网址：www.javathinker.org                *
 ***************************************************/