Serializable中的Transient

下面是代码，你懂的。

 

 

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Date;

public class LoggingInfo implements java.io.Serializable {

	/**
	 * 
	 */
	private static final long serialVersionUID = -6134850492552383232L;

	private Date loggingDate = new Date();
	private String uid;
	private transient String pwd;
	private transient String code;

	LoggingInfo(String user, String password) {
		uid = user;
		pwd = password;
		code = "验证码";
	}

	public String toString() {
		String password = null;
		if (pwd == null) {
			password = "NOT SET";
		} else {
			password = pwd;
		}
		if (code == null) {
			code = "实例中变量code修饰为transient，将它写入磁盘，并且再将它从磁盘中读出，仍然看到读回的对象打印code为 null。当从磁盘中读出某个类的实例时，实际上并不会执行这个类的构造函数，而是载入了一个该类对象的持久化状态，并将这个状态赋值给该类的另一个对象";
		}
		return "logon info: \n"
				+ "user: " + uid + "\n"
				+ "logging date : " + loggingDate.toString() + "\n"
				+ "password: " + password + "\n"
				+ "code: " + code + "\n";
	}

	public static void main(String[] args) {
		LoggingInfo logInfoA = new LoggingInfo("MIKE", "MECHANICS");
		System.out.println(logInfoA.toString());
		try {
			ObjectOutputStream o = new ObjectOutputStream(new FileOutputStream("logInfo.out"));
			o.writeObject(logInfoA);
			o.close();
		} catch (Exception e) {
			// deal with exception
		}
		try {
			ObjectInputStream in = new ObjectInputStream(new FileInputStream("logInfo.out"));
			LoggingInfo logInfo = (LoggingInfo) in.readObject();
			System.out.println(logInfo.toString());
		} catch (Exception e) {
			// deal with exception
		}
	}
}

 

Java的序列化机制只序列化对象的属性值，而不会去序列化什么所谓的方法。
Transient的数据将不会被实例化。