transient关键字

transient 短暂的，临时的

java中一个对象只要实现了Serializable接口，这个对象就可以被序列化。但是如果你想要在序列化过程中规避掉某个成员变量，只要在该变量前添加关键字transient就行（对静态变量无效）

测试代码如下：

public class TransientTest
{
    public static void main(String[] args) throws IOException, ClassNotFoundException
    {
        A a = new A(2, "a");
        System.out.println(a);
        try
        {
            FileOutputStream fos = new FileOutputStream("d://mm.txt");
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(a);
            
            FileInputStream fis = new FileInputStream("d://mm.txt");
            ObjectInputStream ois = new ObjectInputStream(fis);
            A newA = (A) ois.readObject();
            System.out.println(newA);
        }
        catch (FileNotFoundException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

class A implements Serializable
{
    transient static int num = 5;
    int a;
    transient String b;
    public A(int a,String b)
    {
        this.a = a;
        this.b = b;
    }
    @Override
    public String toString()
    {
        return "a = " + a +"; b = " + b +"; num = " + num;
    } 
}

 运行后控制台打印：

a = 2; b = a; num = 5

a = 2; b = null; num = 5