Java中volatile和transient关键字的区别

就像其他编程语言一样，Java也有一组保留的关键词，它们具有特殊的含义。在这篇文章中，我们将看到关键字 volatile 和 transient 之间的区别。

在讨论这些区别之前，让我们首先了解它们各自的实际含义。

volatile关键字

volatile 关键字用于标记JVM和线程从主内存读取其值，而不是利用线程栈中的缓存值。它被用于java的并发编程中。

class YiibaiDemo extends Thread {

    // using volatile
    volatile boolean working = true;

    // if non-volatile it will sleep in main and  runtime error will coocur
    public void run()
    {
        long count = 0;
        while (working) {
            count++;
        }

        System.out.println("Thread terminated." + count);
    }

    // Driver code
    public static void main(String[] args)
        throws InterruptedException
    {
        YiibaiDemo test = new YiibaiDemo();
        test.start();
        Thread.sleep(100);
        System.out.println("After Sleeping in Main");
        test.working = false;
        test.join();
        System.out.println("Working set to " + test.working);
    }
}

transient 关键字

transient关键字与实例变量一起使用，以在序列化过程中消除它。在序列化过程中，暂存字段或变量的值不被保存。

import java.io.*;

class Test implements Serializable {

    // Making Accesskey transient for security
    transient String accessKey;

    // Making age transient as age can be
    // calculated from Date of Birth
    // and current date.
    transient int age;

    // serialize other fields
    String name, address;
    public Test(String accessKey, int age,
                String name, String address)
    {
        this.accessKey = accessKey;
        this.age = age;
        this.name = name;
        this.address = address;
    }
}

public class YiibaiDemo {
    public static void main(String[] args)
        throws Exception
    {
        ObjectInputStream in
            = new ObjectInputStream(
                (new FileInputStream(
                    "login_details.txt")));
        Test obj = (Test)in.readObject();

        /* Transient variable will be shown
        null due to security reasons.*/
        System.out.println("Accesskey: " + obj.accessKey);
        System.out.println("Age: " + obj.age);
        System.out.println("Name: " + obj.name);
        System.out.println("Address: " + obj.address);
    }
}

下表描述了这些区别。