transient的使用
package ig.sd;import java.io.*;import java.util.*;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();}}}