java - Java 扫描器上的 NotSerializableException？

Question

我在解决一个 notSeriazable 问题时遇到了问题，我所有的类都实现了 seriazable，但它总是给我一个关于它的错误。

 java.io.NotSerializableException: java.util.Scanner
 at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeObject(Unknown Source)
at Assign3.main(Assign3.java:119)

Scanner 是一个类，我没有意义。我认为 Scanner 也应该序列化？但我不能碰 Scanner 类。

Bank b = new Bank(100.0);
    try{
        ObjectOutputStream save = new ObjectOutputStream(new FileOutputStream("try.txt"));

        save.writeObject(b);


        save.close();

        }catch(Exception ex){ex.printStackTrace();}



import java.io.Serializable;
import java.util.Scanner;



public class Bank implements Serializable{
/**
 * 
 */
private static final long serialVersionUID = 1L;
private int Maxtransaction = 1000;
public Transaction[] transactions = new Transaction[Maxtransaction];
private int numTransactions = 0;
private double balance;
Scanner sn = new Scanner(System.in);

public Bank()
{
}

public Bank(double balance)
{
    this.balance = balance;
}

public double getBalance()
{
    return balance;
}

public void display()
{
    System.out.print("\nTRANSACTION RECORD:\n");
    for(int i = 0; i<numTransactions;i++)
        {
        System.out.print(transactions[i].toString()+"\n"); 
        }
    System.out.print("BALANCE : $"+getBalance()+"\n");

}

public boolean addTransaction(Category categories)
{
    if(numTransactions>Maxtransaction){return false;}
    else{
    String[] chooseaccountletter = {"c","d"};
    String chooseaccount;
    boolean erroraccount = true;

    System.out.print("\n");
    do{
    System.out.print("Enter a c for credit or d for debit: ");
        chooseaccount = sn.nextLine();
        for(int i = 0 ; i<chooseaccountletter.length;i++)
            {
              if(chooseaccountletter[i].equals(chooseaccount))
              {
                  erroraccount = false;
                  break;
              }
            }
      }while(erroraccount);

    if(chooseaccountletter[0].equals(chooseaccount))
    {
        Transaction credit = new CreditTransaction();
        credit.getTransactionInfo(categories);
        credit.getAmout();
        balance += credit.getAmout();
        transactions[numTransactions] = credit;
    }//end credit

    if(chooseaccountletter[1].equals(chooseaccount))
    {
        Transaction debit = new DebitTransaction();
        debit.getTransactionInfo(categories);
        debit.getAmout();
        balance += debit.getAmout();
        transactions[numTransactions] = debit;
    }//end debit
    numTransactions++;
    return true;
    }

}

public void displayCategory(String Category)
{   
    double total = 0;
    System.out.print("\nTransactions for Category "+Category+" :\n");


    for(int i = 0; i<numTransactions;i++){
        if(transactions[i].getCategory() == Category)
            {
                System.out.print(transactions[i].toString()+"\n");
                total += transactions[i].getAmout(); 
            }
        }

    System.out.print("Category Balance : $"+total+"\n");
}

}

Answer 1

没有Scanner没有实现 Serializable，因此如果您的 Bank 类包含一个 Scanner 对象，它也不会是可序列化的。您必须删除 Scanner 或将其标记为 transient 或 static 以便 Bank 对象可序列化。 (请注意，将扫描器标记为静态会使它属于该类，而不是 Bank 的单个实例。您最好将其设为 transient 。)