Java中的Serialization机制和transient关键字

下面这两篇文章讲得特别明白，简单的说，就是Serialization机制是 指把类或者基本的数据类型持久化(persistence)到数据流(Stream)中，包括文件、字节流、网络数据流。 

JAVA中实现serialization主要靠两个类：ObjectOuputStream和ObjectInputStream。他们是JAVA IO系统里的OutputStream和InputStream的子类。既然他们是JAVA IO中的流，那么就可以像操作一般的流一样来操作他们。

Java的Serialization机制

http://zzy1943.iteye.com/blog/634418

Java的关键字transient

http://blog.csdn.net/flynetcn/article/details/2142020

这里有一段详细的代码，我还添加了一点点注释便于理解：

import java.io.*; 

import java.util.*; 

public class Logon implements Serializable { 

private static final long serialVersionUID = 1L;

private Date date = new Date(); 

private String username; 

private transient String password;

Logon(String name, String pwd) { 

username = name; 

password = pwd; 

}

public String toString() { 

String pwd = (password == null) ? "(n/a)" : password; 

return "logon info: \n " + 

"username: " + username + 

"\n date: " + date.toString() + 

"\n password: " + pwd; 

}

public static void main(String[] args) { 

Logon a = new Logon("Hulk", "myLittlePony");

System.out.println( "logon a = " + a); 

try { 

ObjectOutputStream o = new ObjectOutputStream( new FileOutputStream("Logon.out")); 

o.writeObject(a); 

o.close(); 

// Delay: 

int seconds = 5; 

long t = System.currentTimeMillis() + seconds * 1000; 

while(System.currentTimeMillis() < t); 

// Now get them back: 

ObjectInputStream in = new ObjectInputStream( new FileInputStream("Logon.out")); 

System.out.println( "Recovering object at " + new Date()); 

a = (Logon)in.readObject(); 

System.out.println( "logon a = " + a); 

} catch(Exception e) { 

e.printStackTrace(); 

} 

} 

}