Some question bout URLConnection anyone can help me

Question

First Of all, i want to ask something bout URL connection
1. Is it possible to Modifying some files that i accessed via URLConnection without using CGI files ?
2. What is the limitation of URLConnection Class
As far as i know URLConnection Class only providing connection to resources, we can read it directly, but we cannot modify it directly.
Maybe someone Can help me with these class
package TKI.FileBuilder;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class GetData extends HttpServlet
private static final String CONTENT_TYPE = "text/xml; charset=windows-1252";
private static final String DOC_TYPE;
public static String getFilename(String Judul)
{ /*Fungsi untuk mengembalikan lokasi file tempat record akan disimpan */
String Filename= "";
String opener = Judul.substring(0,1);
opener = opener.toLowerCase();
if ((opener.equals("a")) || (opener.equals("b")) || (opener.equals("c")) || (opener.equals("d"))
|| (opener.equals("e")))
Filename = "http://127.0.0.1:8988/Final_Project-Project1-context-root/Admin/flatfiles/flatfileA-E.txt";
else if ((opener.equals("f")) || (opener.equals("g")) || (opener.equals("h")) || (opener.equals("i"))
|| (opener.equals("j")))
Filename = "http://127.0.0.1:8988/Final_Project-Project1-context-root/Admin/flatfiles/flatfileF-J";
else if ((opener.equals("k")) || (opener.equals("l")) || (opener.equals("m")) || (opener.equals("n"))
|| (opener.equals("o")))
Filename = "http://127.0.0.1:8988/Final_Project-Project1-context-root/Admin/flatfiles/flatfileK-O";
else if ((opener.equals("p")) || (opener.equals("q")) || (opener.equals("r")) || (opener.equals("s"))
|| (opener.equals("t")) )
Filename = "http://127.0.0.1:8988/Final_Project-Project1-context-root/Admin/flatfiles/flatfileP-T";
else if ((opener.equals("u")) ||(opener.equals("v")) || (opener.equals("w")) || (opener.equals("x")) || (opener.equals("y"))
|| (opener.equals("z")))
Filename = "http://127.0.0.1:8988/Final_Project-Project1-context-root/Admin/flatfiles/flatfileV-Z";
return Filename;
public void saveWritten(String title, String ID, String name, String Abstract, PrintWriter File)
try
// save data
System.out.println("****\n");
System.out.println(title+"\n");
System.out.println(name+"\n");
System.out.println(ID+"\n");
System.out.println(Abstract+"\n");
System.out.println("****");
File.println("****\n");
File.println(title+"\n");
File.println(name+"\n");
File.println(ID+"\n");
File.println(Abstract+"\n");
File.println("****");
}catch(Exception ae)
ae.printStackTrace();
public void getFile(String Judul,String nama, String Id, String Abstract, HttpServletResponse response)
{/* mengambil dan membuka file dari sisi server
berdasarkan huruf pertama dari judul Tugas akhir
File di Server di bedakan menjadi
- flatfileA-E
- flatfileF-J
- fletfileK-O
- flatfileP-S
- flatfileT-Z
// Memilah String dengan melihat huruf terdepan dari Judul untuk menentukan
// Flatfile mana yang akan dibuka
String Filename = "";
try
// open files
Filename = getFilename(Judul);
URL flatfile = new URL(Filename);
// open URL connection
URLConnection connection = flatfile.openConnection();
// set output True
connection.setDoOutput(true);
// set Write data properties to files via socket connection
PrintWriter Aen = new PrintWriter(connection.getOutputStream());
// save inserted data into flatfile
saveWritten(Judul,Id,nama,Abstract,Aen);
Aen.close();
//view Inserted File
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
while(in.readLine()!= null)
System.out.println(in.readLine());
}catch( Exception ae)
ae.printStackTrace();
public void postData(String Judul, String Nama, String Id, String Abstraksi,HttpServletResponse response)
/*Ambil file sesuaikan dengan judul data masukan ke flatfile*/
getFile(Judul, Nama, Id, Abstraksi,response);
public void init(ServletConfig config) throws ServletException
super.init(config);
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
String J_Ta = "";
String N_Pem = "";
String ID_Pem = "";
String Abs = "";
try
{ // requesting object parameter and variables
J_Ta = request.getParameter("Judul");
N_Pem = request.getParameter("Nama");
ID_Pem = request.getParameter("IDPembuat");
Abs = request.getParameter("Abstraksi");
catch(Exception e)
e.printStackTrace();
// Masukkan semua data ke dalam flat file
postData(J_Ta,N_Pem,ID_Pem,Abs,response);
I'm trying to modify flatfiles using socket connection
But what comes out
No error comes out, but none inserted to the files

Answer 1

This is a simple edit and replace the existing file:
import java.io.*;
import java.text.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
* Example of file modification via servlet
public class FileEditExample extends HttpServlet {
  File file_ = new File("borg.txt");
  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
    throws IOException, ServletException {
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
      out.println("<html>");
      out.println("<head>");
      out.println("<title>Example file edit servlet</title>");
      out.println("</head>");
      out.println("<body bgcolor='linen'>");
      out.println("<h1>Edit me!</h1>");
      out.println("<form action='" + request.getRequestURI() + "' method='POST'>");
      out.println("<textarea rows='20' cols='80' name='text'>");
      synchronized (file_) {
        BufferedReader reader = null;
        try {
          reader = new BufferedReader(new FileReader(file_));
          String line;
          if ((line=reader.readLine())!=null) {
            while(true) {
              out.print(line);
              line = reader.readLine();
              if (line==null) break;
              out.println();
        } catch (IOException ioe) {
          ioe.printStackTrace(out);
        } finally {
          if (reader!=null) {
            reader.close();
      out.println("</textarea>");
      out.println("<br>");
      out.println("<input type='submit' value='resistance is futile'>");
      out.println("</form>");
      out.println();
      out.println("</body>");
      out.println("</html>");
  public void doPost(HttpServletRequest request,
                    HttpServletResponse response)
    throws IOException, ServletException {
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
      out.println("<html>");
      out.println("<head>");
      out.println("<title>Example file edit servlet</title>");
      out.println("</head>");
      out.println("<body bgcolor=\"white\">");
      out.println("<h1>Now you've done it!</h1>");
      out.println("<pre>");
      synchronized (file_) {
        BufferedReader reader = null;
        PrintWriter writer = null;
        try {
          reader = new BufferedReader(request.getReader());
          writer = new PrintWriter(new FileWriter(file_));
          String line;
          while ((line=reader.readLine())!=null) {
            if (line.startsWith("text=")) {
              line = line.substring(5);
              while (true) {
                line = deMimify(line);
                out.print(line);
                writer.print(line);
                line = reader.readLine();
                if (line==null) {
                  break;
                out.println();
                writer.println();
              break;
        } catch (IOException ioe) {
          ioe.printStackTrace(out);
        } finally {
          if (reader!=null) {
            writer.close();
          if (reader!=null) {
            writer.close();
      out.println("</pre>");
      out.println("<a href='" + request.getRequestURI() + "'>Back again</a>");
      out.println("</body>");
      out.println("</html>");
  // decodes mime encoding (probably there's been a utility to do this
  // added at some point, but I wrote this first in '96 and have never
  // bothered to check) 
  static String deMimify (String data) {
    int length = data.length();
    StringBuffer buffer = new StringBuffer(length);
    char ch;
    for (int i=0; i<length; i++) {
      switch (ch=data.charAt(i)) {
        case '+' :
          buffer.append(' ');
          break;
        case '%':
          ch = (char)( Character.digit(data.charAt(i+1), 16) * 16 +
                       Character.digit(data.charAt(i+2), 16) );
          i+=2;
        default:
          buffer.append(ch);
    return buffer.toString();
}Pete