Question

I’m trying to write a simplest java web server program following an instruction which is only able to handle GET inquiry. The main idea is to get an ObjectOutputStream from a socket, use an ObjectInputStream to open a local file and write it into the ObjectOutputStream byte by byte.

The serve() is attached below. It takes an ObjectOutputStream I want to write to and the path to a file as parameters.

public void serve(ObjectOutputStream out, String path) throws IOException {
    System.out.println("Trying to serve: " + path);
    File file = new File(path);
    if (!file.exists()) {
        //return an HTTP 404
    } else {
        out.writeBytes("HTTP/1.1 200 OK\n\n");
        ObjectInputStream in = null;
        try {
            in = new ObjectInputStream(new FileInputStream(file));
            int data;
            while ((data = in.readByte()) != -1) {
                out.writeByte((byte) data);
            }
            System.out.println("Request valid.");
        } catch (IOException  e) {
            System.out.println("Error in serve(): sending file: " + e.getMessage());
        } finally {
            if (null != in)
                in.close();
        }
    }
}

However, when I use browser to access localhost:8080 (the port is at 8080), it throws an IOException

 invalid stream header: 3C68746D

I believe it’s in out.writeByte((byte) data); step. Can you tell me why and how to fix it? Thanks ahead.

Answer 1

ObjectInputStream and ObjectOutputStream are used for object serialization in java.
Please refer the below article to understand the usage of these streams.

http://java.sun.com/developer/technicalArticles/Programming/serialization/

For your code, you could better use BufferedInputStream and BufferedOutputStream wherever you find corresponding Object Stream.