我一直在获取java.io.NotSerializableException：java.io.ObjectOutputStream

Question

这是我一直在尝试的代码

import java.util.Scanner;
import java.io.*;

abstract class Account implements Serializable {
    protected String accountHolderName;
    protected long balance;

    protected ObjectOutputStream accData;

    Scanner input = new Scanner(System.in);
}

class Savings extends Account implements Serializable {

    Savings() throws IOException {
        System.out.print("enter your name: ");
        accountHolderName = input.nextLine();
        System.out.print("\n");
        System.out.print("enter your balance: ");
        balance = input.nextLong();
        accData = new ObjectOutputStream(new FileOutputStream(accountHolderName + ".bin"));
        accData.writeObject(this);
        accData.close();
    }
}

class Banking implements Serializable {
    public static void main(String args[]) throws IOException {
        Scanner input = new Scanner(System.in);
        Savings savobj = new Savings();
    }
}

这是我得到的例外

线程“主”中的异常java.io.NotSerializableException：java.io.ObjectOutputStream.writeObject0（未知源）处的java.io.ObjectOutputStream（java.io.ObjectOutputStream.writeSerialData（java.io.ObjectOutputStream.defaultWriteFields（未知源）） java.io.ObjectOutputStream.writeOrdinaryObject处的未知源（Object.java.io.ObjectOutputStream.writeObject0处的未知源）java.io.ObjectOutputStream.writeObject处的Savings。（Banking.java:22）处的未知源） Banking.main（Banking.java:30）

我也尝试使用savobj.accData.writeObj(savobj)from main(），但仍然遇到相同的异常。我该怎么办？

Answer 1

只有实现Serializable接口的原语和类才能被序列化。ObjectOutputStream没有实现此接口。

快速解决方案：ObjectOutputStream在尽可能小的范围内使用，在使用它的方法中声明它，而不是在类中声明它。对其他实用程序类（例如）执行类似操作Scanner。

abstract class Account implements Serializable {
    protected String accountHolderName;
    protected long balance;

    //protected ObjectOutputStream accData;

    //Scanner input = new Scanner(System.in);
}

class Savings extends Account implements Serializable {

    Savings() throws IOException {
        Scanner input = new Scanner(System.in);
        System.out.print("enter your name: ");
        accountHolderName = input.nextLine();
        System.out.print("\n");
        System.out.print("enter your balance: ");
        balance = input.nextLong();
        ObjectOutputStream accData = new ObjectOutputStream(new FileOutputStream(accountHolderName + ".bin"));
        accData.writeObject(this);
        accData.close();
    }
}

另一个解决方案可能只是将这些字段标记为，transient这样它们就不会被序列化/反序列化：

abstract class Account implements Serializable {
    protected String accountHolderName;
    protected long balance;

    protected transient ObjectOutputStream accData;

     transient Scanner input = new Scanner(System.in);
}