==== 'My own HTTP' server sample ====
Let's create an empty Java project, Then create files called //404.html// and an //index.html// with the following content. Let's note that the error handling is redundant, i.e. the handling of //errors 404// and //501// is written twice.
**Task**: create a generic error handling function to return errors to the client side.
Content of //404.html//:
File not found error
Content of //index.html//:
My HTTP server works
Link not working
Content of //JavaHTTPServer.java//:
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;
import java.util.StringTokenizer;
public class JavaHTTPServer implements Runnable {
static final File WEB_ROOT = new File(".");
static final String DEFAULT_FILE = "index.html";
static final String FILE_NOT_FOUND = "404.html";
private Socket connect;
public JavaHTTPServer(Socket c) {
connect = c;
}
public static void main(String[] args) {
try {
ServerSocket serverConnect = new ServerSocket(8080);
System.out.println("Server started.\nListening for connections on port : 8080 ...\n");
while (true) {
JavaHTTPServer myServer = new JavaHTTPServer(serverConnect.accept());
Thread thread = new Thread(myServer);
thread.start();
}
} catch (IOException e) {
System.err.println("Server Connection error : " + e.getMessage());
}
}
@Override
public void run() {
BufferedReader in = null;
PrintWriter out = null;
BufferedOutputStream dataOut = null;
String fileRequested = null;
try {
in = new BufferedReader(new InputStreamReader(connect.getInputStream()));
out = new PrintWriter(connect.getOutputStream());
dataOut = new BufferedOutputStream(connect.getOutputStream());
String input = in.readLine();
StringTokenizer parse = new StringTokenizer(input);
String method = parse.nextToken().toUpperCase(); // we get the HTTP method of the client
// we get file requested
fileRequested = parse.nextToken().toLowerCase();
// we support only GET and HEAD methods, we check
if (method.equals("GET") || method.equals("HEAD")) {
// GET or HEAD method
if (fileRequested.endsWith("/")) {
fileRequested += DEFAULT_FILE;
}
File file = new File(WEB_ROOT, fileRequested);
int fileLength = (int) file.length();
String content = getContentType(fileRequested);
if (method.equals("GET")) { // GET method so we return content
byte[] fileData = readFileData(file, fileLength);
// send HTTP Headers
out.println("HTTP/1.1 200 OK");
out.println("Server: Java HTTP Server v1.0");
out.println("Date: " + new Date());
out.println("Content-type: " + content);
out.println("Content-length: " + fileLength);
out.println(); // blank line between headers and content, very important !
out.flush(); // flush character output stream buffer
dataOut.write(fileData, 0, fileLength);
dataOut.flush();
}
}
} catch (FileNotFoundException fnfe) {
try {
fileNotFound(out, dataOut, fileRequested);
} catch (IOException ioe) {
System.err.println("Error with file not found exception : " + ioe.getMessage());
}
} catch (IOException ioe) {
System.err.println("Server error : " + ioe);
} finally {
try {
in.close();
out.close();
dataOut.close();
connect.close(); // we close socket connection
} catch (Exception e) {
System.err.println("Error closing stream : " + e.getMessage());
}
}
}
private byte[] readFileData(File file, int fileLength) throws IOException {
FileInputStream fileIn = null;
byte[] fileData = new byte[fileLength];
try {
fileIn = new FileInputStream(file);
fileIn.read(fileData);
} finally {
if (fileIn != null)
fileIn.close();
}
return fileData;
}
// return supported MIME Types
private String getContentType(String fileRequested) {
if (fileRequested.endsWith(".htm") || fileRequested.endsWith(".html"))
return "text/html";
else
return "text/plain";
}
private void fileNotFound(PrintWriter out, OutputStream dataOut, String fileRequested) throws IOException {
File file = new File(WEB_ROOT, FILE_NOT_FOUND);
int fileLength = (int) file.length();
String content = "text/html";
byte[] fileData = readFileData(file, fileLength);
out.println("HTTP/1.1 404 File Not Found");
out.println("Server: Java HTTP Server v1.0");
out.println("Date: " + new Date());
out.println("Content-type: " + content);
out.println("Content-length: " + fileLength);
out.println(); // blank line between headers and content, very important !
out.flush(); // flush character output stream buffer
dataOut.write(fileData, 0, fileLength);
dataOut.flush();
}
}
**Task**: refactor the code and eliminate duplicate parts. Let's create a separate function to return a general HTTP response::
out.println("HTTP/1.1 200 OK");
out.println("Server: Java HTTP Server v1.0");
out.println("Date: " + new Date());
out.println("Content-type: " + content);
out.println("Content-length: " + fileLength);
out.println(); // blank line between headers and content, very important !
out.flush(); // flush character output stream buffer
**Task**: modify the source code so that it can also return images. To do this, first add