在Java中读取txt文件时获取EOFException

Question

I have Google for a while but I still get confused. When I used FileOutputStream to write some texts into a txt file and then use FileInputStream to read my file, everything was right. But when I typed some words manually to my txt file, and then save in UTF-8 format, I got EOFException. Here is my input code:

StringBuilder s = new StringBuilder();
FileInputStream inputStream = new FileInputStream("filename");
DataInputStream in = new DataInputStream(inputStream);
while (in.available()>0) {
    s.append(in.readUTF());
}
in.close();
System.out.println(s); 

Answer 1

• A file that can be read by readUTF() must have been written by writeUTF() . Not by FileOutputStream .
• A file written by writeUTF() is not a text file. It is a file of sequences of 16-bit length words and strings in a modified encoding, as described in the Javadoc.
• available() > 0 is not a valid test for end of file.

As you state it's a text file, and as your code isn't working, I suggest you should be using BufferedReader.readLine() . And no ready() tests. readLine() will return null at end of stream.

Answer 2

Javadoc for DataInputStream says the following: "An application uses a data output stream to write data that can later be read by a data input stream". So it is probably not a good idea to read manually-written text from file using DataInputStream.

Consider using FileInputStream#read() method if you need to read bytes or FileReader#read() if you need to read characters.

Answer 3

Consider using FileInputStream to read the file, ie:

public static void main(String[] args) throws Exception {
    StringBuilder s = new StringBuilder();
    FileInputStream inputStream = new FileInputStream("file.txt");
    int content;
    while ((content = inputStream.read()) != -1) {
        s.append((char) content);
    }
    inputStream.close();
    System.out.println(s);
}