Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Simple HTTP Web Server made in Java for a tutorial on the SSaurel's Blog
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;
// The tutorial can be found just here on the SSaurel's Blog :
// https://www.ssaurel.com/blog/create-a-simple-http-web-server-in-java
// Each Client Connection will be managed in a dedicated Thread
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";
static final String METHOD_NOT_SUPPORTED = "not_supported.html";
// port to listen connection
static final int PORT = 8080;
// verbose mode
static final boolean verbose = true;
// Client Connection via Socket Class
private Socket connect;
public JavaHTTPServer(Socket c) {
connect = c;
}
public static void main(String[] args) {
try {
ServerSocket serverConnect = new ServerSocket(PORT);
System.out.println("Server started.\nListening for connections on port : " + PORT + " ...\n");
// we listen until user halts server execution
while (true) {
JavaHTTPServer myServer = new JavaHTTPServer(serverConnect.accept());
if (verbose) {
System.out.println("Connecton opened. (" + new Date() + ")");
}
// create dedicated thread to manage the client connection
Thread thread = new Thread(myServer);
thread.start();
}
} catch (IOException e) {
System.err.println("Server Connection error : " + e.getMessage());
}
}
@Override
public void run() {
// we manage our particular client connection
BufferedReader in = null; PrintWriter out = null; BufferedOutputStream dataOut = null;
String fileRequested = null;
try {
// we read characters from the client via input stream on the socket
in = new BufferedReader(new InputStreamReader(connect.getInputStream()));
// we get character output stream to client (for headers)
out = new PrintWriter(connect.getOutputStream());
// get binary output stream to client (for requested data)
dataOut = new BufferedOutputStream(connect.getOutputStream());
// get first line of the request from the client
String input = in.readLine();
// we parse the request with a string tokenizer
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")) {
if (verbose) {
System.out.println("501 Not Implemented : " + method + " method.");
}
// we return the not supported file to the client
File file = new File(WEB_ROOT, METHOD_NOT_SUPPORTED);
int fileLength = (int) file.length();
String contentMimeType = "text/html";
//read content to return to client
byte[] fileData = readFileData(file, fileLength);
// we send HTTP Headers with data to client
out.println("HTTP/1.1 501 Not Implemented");
out.println("Server: Java HTTP Server from SSaurel : 1.0");
out.println("Date: " + new Date());
out.println("Content-type: " + contentMimeType);
out.println("Content-length: " + fileLength);
out.println(); // blank line between headers and content, very important !
out.flush(); // flush character output stream buffer
// file
dataOut.write(fileData, 0, fileLength);
dataOut.flush();
} else {
// 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 from SSaurel : 1.0");
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();
}
if (verbose) {
System.out.println("File " + fileRequested + " of type " + content + " returned");
}
}
} 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());
}
if (verbose) {
System.out.println("Connection closed.\n");
}
}
}
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 from SSaurel : 1.0");
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();
if (verbose) {
System.out.println("File " + fileRequested + " not found");
}
}
}
@Ruhasi

This comment has been minimized.

Copy link

commented Feb 21, 2019

HI
In this server css not working. Is there any way to fix it??

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.