Java implements simple web server instances and Java web Server instances

Java implements simple web server instances and Java web Server instances

Java simple example of web server implementation

Instance code:

import java.util.*;  // Chapter 8, Listing 3 public class WebServerDemo {   // Directory of HTML pages and other files   protected String docroot;   // Port number of web server   protected int port;   // Socket for the web server   protected ServerSocket ss;    // Handler for a HTTP request   class Handler extends Thread {     protected Socket socket;     protected PrintWriter pw;     protected BufferedOutputStream bos;     protected BufferedReader br;     protected File docroot;      public Handler(Socket _socket, String _docroot) throws Exception {       socket = _socket;       // Get the absolute directory of the filepath       docroot = new File(_docroot).getCanonicalFile();     }      public void run() {       try {         // Prepare our readers and writers         br = new BufferedReader(new InputStreamReader(             socket.getInputStream()));         bos = new BufferedOutputStream(socket.getOutputStream());         pw = new PrintWriter(new OutputStreamWriter(bos));          // Read HTTP request from user (hopefully GET /file...... )         String line = br.readLine();          // Shutdown any further input         socket.shutdownInput();          if (line == null) {           socket.close();           return;         }         if (line.toUpperCase().startsWith("GET")) {           // Eliminate any trailing ? data, such as for a CGI GET           // request           StringTokenizer tokens = new StringTokenizer(line, " ?");           tokens.nextToken();           String req = tokens.nextToken();            // If a path character / or / is not present, add it to the           // document root           // and then add the file request, to form a full filename           String name;           if (req.startsWith("/") || req.startsWith("//"))             name = this.docroot + req;           else             name = this.docroot + File.separator + req;            // Get absolute file path           File file = new File(name).getCanonicalFile();            // Check to see if request doesn't start with our document           // root ....           if (!file.getAbsolutePath().startsWith(               this.docroot.getAbsolutePath())) {             pw.println("HTTP/1.0 403 Forbidden");             pw.println();           }           // ... if it's missing .....           else if (!file.exists()) {             pw.println("HTTP/1.0 404 File Not Found");             pw.println();           }           // ... if it can't be read for security reasons ....           else if (!file.canRead()) {             pw.println("HTTP/1.0 403 Forbidden");             pw.println();           }           // ... if its actually a directory, and not a file ....           else if (file.isDirectory()) {             sendDir(bos, pw, file, req);           }           // ... or if it's really a file           else {             sendFile(bos, pw, file.getAbsolutePath());           }         }         // If not a GET request, the server will not support it         else {           pw.println("HTTP/1.0 501 Not Implemented");           pw.println();         }          pw.flush();         bos.flush();       } catch (Exception e) {         e.printStackTrace();       }       try {         socket.close();       } catch (Exception e) {         e.printStackTrace();       }     }      protected void sendFile(BufferedOutputStream bos, PrintWriter pw,         String filename) throws Exception {       try {         java.io.BufferedInputStream bis = new java.io.BufferedInputStream(             new FileInputStream(filename));         byte[] data = new byte[10 * 1024];         int read = bis.read(data);          pw.println("HTTP/1.0 200 Okay");         pw.println();         pw.flush();         bos.flush();          while (read != -1) {           bos.write(data, 0, read);           read = bis.read(data);         }         bos.flush();       } catch (Exception e) {         pw.flush();         bos.flush();       }     }      protected void sendDir(BufferedOutputStream bos, PrintWriter pw,         File dir, String req) throws Exception {       try {         pw.println("HTTP/1.0 200 Okay");         pw.println();         pw.flush();          pw.print("
Thank you for reading this article. I hope it will help you. Thank you for your support for this site!