import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

/**
 * @description 使用transient关键字不序列化某个变量
 *    注意读取的时候，读取数据的顺序一定要和存放数据的顺序保持一致
 *    
 * @author Alexia
 * @date 2013-10-15
 * http://www.manongjc.com/article/1609.html 
 */
public class TransientTest {

  public static void main(String[] args) {

    User user = new User();
    user.setUsername("Alexia");
    user.setPasswd("123456");

    System.out.println("read before Serializable: ");
    System.out.println("username: " + user.getUsername());
    System.err.println("password: " + user.getPasswd());

    try {
      ObjectOutputStream os = new ObjectOutputStream(
          new FileOutputStream("C:/user.txt"));
      os.writeObject(user); // 将User对象写进文件
      os.flush();
      os.close();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
    try {
      ObjectInputStream is = new ObjectInputStream(new FileInputStream(
          "C:/user.txt"));
      user = (User) is.readObject(); // 从流中读取User的数据
      is.close();

      System.out.println("\nread after Serializable: ");
      System.out.println("username: " + user.getUsername());
      System.err.println("password: " + user.getPasswd());

    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    }
  }
}

class User implements Serializable {
  private static final long serialVersionUID = 8294180014912103005L; 

  private String username;
  private transient String passwd;

  public String getUsername() {
    return username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getPasswd() {
    return passwd;
  }

  public void setPasswd(String passwd) {
    this.passwd = passwd;
  }

}

read before Serializable: 
username: Alexia
password: 123456

read after Serializable: 
username: Alexia
password: null

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

/**
 * @description 使用transient关键字不序列化某个变量
 *    注意读取的时候，读取数据的顺序一定要和存放数据的顺序保持一致
 *    
 * @author Alexia
 * @date 2013-10-15
 * http://www.manongjc.com
 */
public class TransientTest {

  public static void main(String[] args) {

    User user = new User();
    user.setUsername("Alexia");
    user.setPasswd("123456");

    System.out.println("read before Serializable: ");
    System.out.println("username: " + user.getUsername());
    System.err.println("password: " + user.getPasswd());

    try {
      ObjectOutputStream os = new ObjectOutputStream(
          new FileOutputStream("C:/user.txt"));
      os.writeObject(user); // 将User对象写进文件
      os.flush();
      os.close();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
    try {
      // 在反序列化之前改变username的值
      User.username = "jmwang";

      ObjectInputStream is = new ObjectInputStream(new FileInputStream(
          "C:/user.txt"));
      user = (User) is.readObject(); // 从流中读取User的数据
      is.close();

      System.out.println("\nread after Serializable: ");
      System.out.println("username: " + user.getUsername());
      System.err.println("password: " + user.getPasswd());

    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    }
  }
}

class User implements Serializable {
  private static final long serialVersionUID = 8294180014912103005L; 

  public static String username;
  private transient String passwd;

  public String getUsername() {
    return username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getPasswd() {
    return passwd;
  }

  public void setPasswd(String passwd) {
    this.passwd = passwd;
  }

}

read before Serializable: 
username: Alexia
password: 123456

read after Serializable: 
username: jmwang
password: null

import java.io.Externalizable;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;

/**
 * @descripiton Externalizable接口的使用
 * 
 * @author Alexia
 * @date 2013-10-15
 *
 */
public class ExternalizableTest implements Externalizable {

  private transient String content = "是的，我将会被序列化，不管我是否被transient关键字修饰";

  @Override
  public void writeExternal(ObjectOutput out) throws IOException {
    out.writeObject(content);
  }

  @Override
  public void readExternal(ObjectInput in) throws IOException,
      ClassNotFoundException {
    content = (String) in.readObject();
  }

  public static void main(String[] args) throws Exception {

    ExternalizableTest et = new ExternalizableTest();
    ObjectOutput out = new ObjectOutputStream(new FileOutputStream(
        new File("test")));
    out.writeObject(et);

    ObjectInput in = new ObjectInputStream(new FileInputStream(new File(
        "test")));
    et = (ExternalizableTest) in.readObject();
    System.out.println(et.content);

    out.close();
    in.close();
  }
}