Question

我的java程序应该读入并显示用户在提示时输入的.txt文件，将文件中的整数转换为输出.dat文件，然后读入.dat文件并再次显示数字。当我运行我的程序时，它显示文件的内容，并创建.dat文件，但不再读取它。我的代码如下。我需要做什么？

public class InputFile
{
    public static void main(String [] args)
    {
        BufferedReader inputStream = null;

            System.out.print("Enter file name (with .txt extension): ");
            Scanner keys = new Scanner(System.in);
            String inFileName = keys.next();

            try
            {
                inputStream = new BufferedReader (new FileReader(inFileName));
                System.out.println("The file " + inFileName + " contains the following lines:");
                String inFileString = inputStream.readLine();
                while(inFileString != null)
                {
                    System.out.println(inFileString);
                    inFileString = inputStream.readLine();
                }
                inputStream.close();
            }
            catch(FileNotFoundException e)
            {
                System.out.println(inFileName + " not found! Try Again.");
            }
            catch(IOException e)
            {
                System.out.println(e.getMessage());
            }

            String fileName = "numbers.dat";
            try
            {
                ObjectOutputStream outputStream = new ObjectOutputStream(new FileOutputStream(fileName));
                int anInt = 0;
                while(anInt >=0);
                {
                    anInt = Integer.parseInt(inputStream.readLine());
                    outputStream.writeInt(anInt);
                }
                outputStream.close();
            }
            catch(FileNotFoundException e)
            {
                System.out.println("Problem opening file.");
            }
            catch(IOException e)
            {
                System.out.println("Problem with output to the file.");
            }

            try
            {
                ObjectInputStream inputStream2 = new ObjectInputStream(new FileInputStream(fileName));
                System.out.println("The file being read yields:");
                int anInteger = inputStream2.readInt();
                while(anInteger >= 0)
                    {
                        System.out.println(anInteger);
                        anInteger = inputStream2.readInt();
                    }
                inputStream2.close();
            }
            catch(FileNotFoundException e)
            {
                System.out.println("Problem with opening the file.");
            }
            catch(EOFException e)
            {
                System.out.println("Problem reading the file.");
            }
            catch(IOException e)
            {
                System.out.println("There was a problem reading the file.");
            }
    }
}

Answer 1

有一种错误（或者至少我认为这是一种错误的类型）很难发现会使你的第二个循环变得无限。

 (...)
 try
        {
            ObjectOutputStream outputStream = new ObjectOutputStream(new FileOutputStream(fileName));
            int anInt = 0;
            while(anInt >=0);  <=====
            {
                anInt = Integer.parseInt(inputStream.readLine());
                outputStream.writeInt(anInt);
            }
            outputStream.close();
        }

删除此';'过了一会儿，我想它会正常运行。

Answer 2

您没有写入输出流，因为到那时inputStream已经耗尽并且已关闭。

创建一个集合来存储第一个文件中的元素。

String inFileName = keys.next();
Collection<String> lines = new ArrayList<String>();
...
System.out.println(inFileString);
lines.add(inFileString);

...
for(String line : lines){
...
    outputStream.write(Integer.parseInt(line));
...
}

为什么我的程序没有打开我的.dat文件？

2 个答案: