transient关键字的应用——《Thinking in Java》随笔032

使用transient方式修饰过的成员属性不会被写入流中，

就不用实现Externalizable接口来逐个选择成员属性。

 

看下面的例子（摘自Thinking in Java）：

 

//: Logon.java
package c10;

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

/**
*    @time:         下午4:37:21
*    @date:         2017年5月8日
*    @auther:    skyfffire
*    @version:    v0.1
*/
public class Logon implements Serializable {
    private static final long serialVersionUID = -1348372416300355940L;
    
    private Date date = new Date();
    private String username;
    private transient String password;
    
    Logon(String _username, String _password) {
        username = _username;
        password = _password;
    }
    
    /**
     * @return the date
     */
    public Date getDate() {
        return date;
    }

    /**
     * @param date the date to set
     */
    public void setDate(Date date) {
        this.date = date;
    }
    /**
     * @return the username
     */
    public String getUsername() {
        return username;
    }
    /**
     * @param username the username to set
     */
    public void setUsername(String username) {
        this.username = username;
    }
    /**
     * @return the password
     */
    public String getPassword() {
        return password;
    }
    /**
     * @param password the password to set
     */
    public void setPassword(String password) {
        this.password = password;
    }
    /**
     * @return the serialversionuid
     */
    public static long getSerialversionuid() {
        return serialVersionUID;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return "Logon [date=" + date + 
                ", username=" + username + 
                ", password=" + password + "]";
    }
    
    public static void main(String[] args) {
        Logon a = new Logon("Hulk", "Haha");
        
        System.out.println("Logon a = " + a);
        
        try {
            ObjectOutputStream out = 
                    new ObjectOutputStream(
                            new FileOutputStream("Logon.out"));
            out.writeObject(a);
            out.close();
            
            // 1.线程式暂停
            try {
                Thread.sleep(2000);
            } catch (Exception e) {
                e.printStackTrace();
            }

            // 2.循环式暂停
            int seconds = 2;
            // currentTimeMillis()获取当前系统时间
            long t = System.currentTimeMillis() + seconds * 1000;
            while (System.currentTimeMillis() < t);
            
            ObjectInputStream in = 
                    new ObjectInputStream(new FileInputStream("Logon.out"));
            Logon b = (Logon) in.readObject();
            System.out.println("Logon b = " + b);
            in.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

///:~