Have a simple HTTP serverTag(s): Networking


Since Java 1.6, there's a built-in HTTP server included with the JDK.

The HttpServer provides a simple high-level Http server API, which can be used to build embedded HTTP servers.

import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;

/*
 * a simple static http server
*/
public class SimpleHttpServer {

  public static void main(String[] args) throws Exception {
    HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0);
    server.createContext("/test", new MyHandler());
    server.setExecutor(null); // creates a default executor
    server.start();
  }

  static class MyHandler implements HttpHandler {
    public void handle(HttpExchange t) throws IOException {
      String response = "Welcome Real's HowTo test page";
      t.sendResponseHeaders(200, response.length());
      OutputStream os = t.getResponseBody();
      os.write(response.getBytes());
      os.close();
    }
  }
}
Compile and execute. To access the local server, open a browser at http://localhost:8000/test.

The next HttpServer provides 2 contexts :

  • http://localhost:8000/info to display an informative message.
  • http://localhost:8000/get to download a specific PDF to the browser.
    import java.io.BufferedInputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.net.InetSocketAddress;
    
    import com.sun.net.httpserver.HttpExchange;
    import com.sun.net.httpserver.HttpHandler;
    import com.sun.net.httpserver.HttpServer;
    import com.sun.net.httpserver.Headers;
    
    public class SimpleHttpServer {
    
      public static void main(String[] args) throws Exception {
        HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0);
        server.createContext("/info", new InfoHandler());
        server.createContext("/get", new GetHandler());
        server.setExecutor(null); // creates a default executor
        server.start();
      }
    
      static class InfoHandler implements HttpHandler {
        public void handle(HttpExchange t) throws IOException {
          String response = "Use /get to download a PDF";
          t.sendResponseHeaders(200, response.length());
          OutputStream os = t.getResponseBody();
          os.write(response.getBytes());
          os.close();
        }
      }
    
      static class GetHandler implements HttpHandler {
        public void handle(HttpExchange t) throws IOException {
    
          // add the required response header for a PDF file
          Headers h = t.getResponseHeaders();
          h.add("Content-Type", "application/pdf");
    
          // a PDF (you provide your own!)
          File file = new File ("c:/temp/doc.pdf");
          byte [] bytearray  = new byte [(int)file.length()];
          FileInputStream fis = new FileInputStream(file);
          BufferedInputStream bis = new BufferedInputStream(fis);
          bis.read(bytearray, 0, bytearray.length);
    
          // ok, we are ready to send the response.
          t.sendResponseHeaders(200, file.length());
          OutputStream os = t.getResponseBody();
          os.write(bytearray,0,bytearray.length);
          os.close();
        }
      }
    }
    

    See these related HowTo :

  • Handle URL parameters using the JDK HTTP server
  • Do Basic authentication using the JDK HTTP server
    See also SimpleWeb, an open source http server.
    blog comments powered by Disqus