java io捕获异常

Question

我得到了这个错误：

bill value:$ 0.10
bill value: $0.05
bill value: $0.01
bill value: $100.00
Exception in thread "main" java.io.EOFException
    at java.io.ObjectInputStream$BlockDataInputStream.peekByte(Unknown Source)
    at java.io.ObjectInputStream.readObject0(Unknown Source)
    at java.io.ObjectInputStream.readObject(Unknown Source)
    at ReadMoney.main(ReadMoney.java:12)

==================我的代码：

//import java.util.Date;
public class ReadMoney
{
    public static void main(String argv[]) throws Exception
    {
        FileInputStream fis = new FileInputStream("money.out");
        ObjectInputStream ois = new ObjectInputStream(fis);
        Object read;
        try
        {
            while ((read = ois.readObject()) != null)
            {
                if (read instanceof Bill)
                {
                    System.out.println("bill value: " + read);
                }
                else if (read instanceof Quarter)
                {
                }// while
                else if (read instanceof Dime)
                {
                    System.out.println("bill value:" + read);
                }
                else if (read instanceof Nickel)
                {
                    System.out.println("bill value:" + read);
                }
                else if (read instanceof Penny)
                {
                    System.out.println("bill value:" + read);
                }
                else if (read instanceof Bill)
                {
                    System.out.println("bill value:" + read );
                }

            Money quarter = (Money) ois.readObject();
            System.out.println("Quarter: "+ quarter);
            System.out.println("Quarter: "+ quarter);
            Money dime = (Money) ois.readObject();
            System.out.println("Dime:" + dime);
            Money nickel = (Money)ois.readObject();
            System.out.println("Nickel:" + nickel);
            Money penny = (Money) ois.readObject();
            System.out.println("Penny:" + penny);
            Money bill = (Money) ois.readObject();
            System.out.println("Bill: " + bill);
        }// try
        } catch (IllegalBillException ibe)
        {
            System.out.println("End of file reached");
        }
        ois.close();
        fis.close();
    }// main
}// class

我非常确定我的try和catch块是正确的，但是我的程序没有打印两个季度的值，而且由于某种奇怪的原因，文本也没有显示“文件末尾到达”。=/

Answer 1

您正在捕获IllegalBillException (不管它是什么)，但是您没有捕获EOFException (或者它是超类，IOException)。

Answer 2

问题在于，使用null检查来测试EOF的while条件并不“保护”"}// try“之后的内容，因此在该点之后的readObject调用将尝试读取EOF之外的内容并获取异常。

你需要以某种方式重组你的逻辑。

捕获EOFException将使异常“消失”，但不会修复您的错误。