Problems reading an SSL server socket stream using readByte()
Hi I'm trying to read an SSL server socket stream using readByte(). I need to use readByte() because my program acts an LDAP proxy (receives LDAP messages from an LDAP client then passes them onto an actual LDAP server. It works fine with normal LDAP data streams but once an SSL data stream is introduced, readByte just hangs! Here is my code.....
help!!! anyone?... anyone?
1. SSL Socket is first read into " InputStream input"
public void run()
Authorization auth = new Authorization();
try {
InputStream input = client.getInputStream();
while (true)
{ StandLdapCommand command;
try
command = new StandLdapCommand(input);
Authorization t = command.get_auth();
if (t != null )
auth = t;
catch( SocketException e )
{ // If socket error, drop the connection
Message.Info( "Client connection closed: " + e );
close( e );
break;
catch( EOFException e )
{ // If socket error, drop the connection
Message.Info( "Client connection close: " + e );
close( e );
break;
catch( Exception e )
//Way too many of these to trace them!
Message.Error( "Command not processed due to exception");
close( e );
break;
//continue;
processor.processBefore(auth, command);
try
Thread.sleep(40); //yield to other threads
catch(InterruptedException ie) {}
catch (Exception e)
close(e);
2 Then data is sent to an intermediate function
from this statement in the function above: command = new StandLdapCommand(input);
public StandLdapCommand(InputStream in) throws IOException
message = LDAPMessage.receive(in);
analyze();
Then finally, the read function where it hangs at "int tag = (int)din.readByte(); "
public static LDAPMessage receive(InputStream is) throws IOException
* LDAP Message Format =
* 1. LBER_SEQUENCE -- 1 byte
* 2. Length -- variable length = 3 + 4 + 5 ....
* 3. ID -- variable length
* 4. LDAP_REQ_msg -- 1 byte
* 5. Message specific structure -- variable length
DataInputStream din = new DataInputStream(is);
int tag = (int)din.readByte(); // sequence tag// sequence tag
I suspect you are actually getting an Exception and not tracing the cause properly and then doing a sleep and then getting another Exception. Never ever catch an exception without tracing what it actually is somewhere.
Also I don't know what the sleep is supposed to be for. You will block in readByte() until something comes in, and that should be enough yielding for anybody. The sleep is just literally a waste of time.
Similar Messages
-
Problem trying to read an SSL server socket stream using readByte().
Hi I'm trying to read an SSL server socket stream using readByte(). I need to use readByte() because my program acts an LDAP proxy (receives LDAP messages from an LDAP client then passes them onto an actual LDAP server. It works fine with normal LDAP data streams but once an SSL data stream is introduced, readByte just hangs! Here is my code.....
help!!! anyone?... anyone?
1. SSL Socket is first read into " InputStream input"
public void run()
Authorization auth = new Authorization();
try {
InputStream input = client.getInputStream();
while (true)
{ StandLdapCommand command;
try
command = new StandLdapCommand(input);
Authorization t = command.get_auth();
if (t != null )
auth = t;
catch( SocketException e )
{ // If socket error, drop the connection
Message.Info( "Client connection closed: " + e );
close( e );
break;
catch( EOFException e )
{ // If socket error, drop the connection
Message.Info( "Client connection close: " + e );
close( e );
break;
catch( Exception e )
//Way too many of these to trace them!
Message.Error( "Command not processed due to exception");
close( e );
break;
//continue;
processor.processBefore(auth, command);
try
Thread.sleep(40); //yield to other threads
catch(InterruptedException ie) {}
catch (Exception e)
close(e);
2 Then data is sent to an intermediate function
from this statement in the function above: command = new StandLdapCommand(input);
public StandLdapCommand(InputStream in) throws IOException
message = LDAPMessage.receive(in);
analyze();
Then finally, the read function where it hangs at "int tag = (int)din.readByte(); "
public static LDAPMessage receive(InputStream is) throws IOException
* LDAP Message Format =
* 1. LBER_SEQUENCE -- 1 byte
* 2. Length -- variable length = 3 + 4 + 5 ....
* 3. ID -- variable length
* 4. LDAP_REQ_msg -- 1 byte
* 5. Message specific structure -- variable length
DataInputStream din = new DataInputStream(is);
int tag = (int)din.readByte(); // sequence tag// sequence tagI suspect you are actually getting an Exception and not tracing the cause properly and then doing a sleep and then getting another Exception. Never ever catch an exception without tracing what it actually is somewhere.
Also I don't know what the sleep is supposed to be for. You will block in readByte() until something comes in, and that should be enough yielding for anybody. The sleep is just literally a waste of time. -
Reading text from server socket stream
I have a basic cd input program i've been trying to figure out the following problem for a while now, the user enters the artist and title etc and then a DOM (XML) file is created in memory this is then sent to the server. The server then echos back the results which is later printed on a html page by reading the replys from the server line by line.
The server must be run it listens for clients connecting the clients connect and send DOM documents through the following jsp code.
<%@page import="java.io.*"%>
<%@page import="java.net.*"%>
<%@page import="javax.xml.parsers.*"%>
<%@page import="org.w3c.dom.*"%>
<%@page import="org.apache.xml.serialize.*"%>
<%!
public static final String serverHost = "cdserver";
public static final int serverPort = 10151;
%>
<hr />
<pre>
<%
Socket mySocket = null; // socket object
PrintWriter sockOut = null; // to send data to the socket
BufferedReader sockIn = null; // to receive data from the socket
try {
// #1 add line that creates a client socket
mySocket = new Socket(serverHost, serverPort);
// #2 add lines that create input and output streams
// attached to the socket you just created
sockOut = new PrintWriter(mySocket.getOutputStream(), true);
sockIn = new BufferedReader(new InputStreamReader(mySocket.getInputStream()));
} catch (UnknownHostException e) {
throw e; // This time the JSP can handle the exception, not us
} catch (IOException e) {
throw e; // This time the JSP can handle the exception, not us
String cdTitle, cdArtist, track1Title, track1Time, track1Rating;
// Retrieve the HTML form field values
cdTitle = request.getParameter("cdtitle");
cdArtist = request.getParameter("cdartist");
track1Title = request.getParameter("track1title");
track1Time = request.getParameter("track1time");
track1Rating = request.getParameter("track1rating");
// Create a new DOM factory, and from that a new DOM builder object
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
// Note that we are creating a new (empty) document
Document document = builder.newDocument();
// The root element of our document wil be <cd>
// It gets stored as the child node of the whole document (it is the root)
Element rootElement = document.createElement("cd");
document.appendChild(rootElement);
// Create an element for the CD title called <title>
Element cdTitleElement = document.createElement("title");
// Add a text code under the <title> element with the value that
// the user entered into the title field of the web form (cdTitle)
cdTitleElement.appendChild(document.createTextNode(cdTitle));
// Place the <title> element underneath the <cd> element in the tree
rootElement.appendChild(cdTitleElement);
// Create an <artist> element with the form data, place underneath <cd>
Element cdArtistElement = document.createElement("artist");
cdArtistElement.appendChild(document.createTextNode(cdArtist));
rootElement.appendChild(cdArtistElement);
// Create a <tracklist> element and place it underneath <cd> in the tree
// Note that it has no text node associated with it (it not a leaf node)
Element trackListElement = document.createElement("tracklist");
rootElement.appendChild(trackListElement);
// In this example we only have one track, so it is not necessary to
// use a loop (in fact it is quite silly)
// But the code below is included to demonstrate how you could loop
// through and add a set of different tracks one by one if you
// needed to (although you would need to have the track data already
// stored in an array or a java.util.Vector or similar
int numTracks = 1;
for (int i=0; i<numTracks; i++) {
String trackNum = Integer.toString(i+1);
Element trackElement = document.createElement("track");
trackElement.setAttribute("id", trackNum);
trackListElement.appendChild(trackElement);
// Track title element called <title>, placed underneath <track>
Element trackTitleElement = document.createElement("title");
trackTitleElement.appendChild(document.createTextNode(track1Title));
trackElement.appendChild(trackTitleElement);
// Track time element called <time>, placed underneath <track>
Element trackTimeElement = document.createElement("time");
trackTimeElement.appendChild(document.createTextNode(track1Time));
trackElement.appendChild(trackTimeElement);
// Track rating element called <rating>, placed underneath <track>
Element trackRatingElement = document.createElement("rating");
trackRatingElement.appendChild(document.createTextNode(track1Rating));
trackElement.appendChild(trackRatingElement);
OutputFormat format = new OutputFormat();
format.setIndenting(true);
// Create a new XMLSerializer that will be used to write out the XML
// This time we will serialize it to the socket
// #3 change this line so that it serializes to the socket,
// not to the "out" object
XMLSerializer serializer = new XMLSerializer(writer, format);
serializer.serialize(document);
// Print out a message to indicate the end of the data, and
// flush the stream so all the data gets sent now
sockOut.println("<!--QUIT-->");
sockOut.flush();
BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
String fromServer;
String fromUser;
#4 add a while loop that reads text from the
server socket input stream, line by line, and prints
it out to the web page, using out.println(...);
Note that because the reply from the server will contain
XML, you will need to call upon the toHTMLString() method
defined below to escape the < and > symbols so that they
will display correctly in the web browser.
Also note that as you receive the reply back from the
server, you should look out for the special <!--QUIT-->
string that will indicate when there is no more data
to receive.
while ((fromServer = sockIn.readLine()) != null) {
out.println(sockIn.readLine());
// If the reply from the server said "QUIT", exit from the
// while loop by using a break statement.
if (fromServer.equals("QUIT")) {
out.println("Connection closed - good bye ...");
// Print the text from the server out to the user's screen
out.println("Reply from Server: " + fromServer);
// Now read a line of text from the keyboard (typed by user)
fromUser = stdIn.readLine();
// If it wasn't null, print it out to the screen, and also
// print a copy of it out to the socket
if (fromUser != null) {
out.println("Client: " + fromUser);
sockOut.println(fromUser);
// Close all the streams we have open, and then close the socket
sockOut.close();
sockIn.close();
mySocket.close();
%>
I'm suppose to modify the commented sections labled with #.
#1,2 are correct but i have doubts on the 3rd and 4th modification.
for #3 i changed so i serializes to the socket not to the "out" object:
from
XMLSerializer serializer = new XMLSerializer(out, format);
to
XMLSerializer serializer = new XMLSerializer(writer, format);
with "out" it prints out some of the results entered but it just hangs i'm thinking it might be the while loop that i added in #4. If i changed it to serialize the socket XMLSerializer serializer = new XMLSerializer(writer, format); it doesn't print out nothing at all; just a blank screen where it hangs.
I can post the rest of the code (server thats in java and cdinput.html) but since i want to keep my post short and if required i'll post it later on i also omitted some of the code where it creates the DOM textnodes etc to keep my post short.On your previous thread, why did you say the server was using http POST and application/xml content type when it quite obviously isn't, but a direct socket communication that abuses XML comments for message end delimiters?
The comments imply you need to wait for "<!--QUIT-->" on a line by itself, but your loop is waiting for "QUIT".
Pete -
Problems Reading SSL server socket data stream using readByte()
Hi I'm trying to read an SSL server socket stream using readByte(). I need to use readByte() because my program acts an LDAP proxy (receives LDAP messages from an LDAP client then passes them onto an actual LDAP server. It works fine with normal LDAP data streams but once an SSL data stream is introduced, readByte just hangs! Here is my code.....
help!!! anyone?... anyone?
1. SSL Socket is first read into " InputStream input"
public void run()
Authorization auth = new Authorization();
try {
InputStream input = client.getInputStream();
while (true)
{ StandLdapCommand command;
try
command = new StandLdapCommand(input);
Authorization t = command.get_auth();
if (t != null )
auth = t;
catch( SocketException e )
{ // If socket error, drop the connection
Message.Info( "Client connection closed: " + e );
close( e );
break;
catch( EOFException e )
{ // If socket error, drop the connection
Message.Info( "Client connection close: " + e );
close( e );
break;
catch( Exception e )
//Way too many of these to trace them!
Message.Error( "Command not processed due to exception");
close( e );
break;
//continue;
processor.processBefore(auth, command);
try
Thread.sleep(40); //yield to other threads
catch(InterruptedException ie) {}
catch (Exception e)
close(e);
2 Then data is sent to an intermediate function
from this statement in the function above: command = new StandLdapCommand(input);
public StandLdapCommand(InputStream in) throws IOException
message = LDAPMessage.receive(in);
analyze();
Then finally, the read function where it hangs at "int tag = (int)din.readByte(); "
public static LDAPMessage receive(InputStream is) throws IOException
* LDAP Message Format =
* 1. LBER_SEQUENCE -- 1 byte
* 2. Length -- variable length = 3 + 4 + 5 ....
* 3. ID -- variable length
* 4. LDAP_REQ_msg -- 1 byte
* 5. Message specific structure -- variable length
DataInputStream din = new DataInputStream(is);
int tag = public static LDAPMessage receive(InputStream is) throws IOException
* LDAP Message Format =
* 1. LBER_SEQUENCE -- 1 byte
* 2. Length -- variable length = 3 + 4 + 5 ....
* 3. ID -- variable length
* 4. LDAP_REQ_msg -- 1 byte
* 5. Message specific structure -- variable length
DataInputStream din = new DataInputStream(is);
int tag = (int)din.readByte(); // sequence tag// sequence tag
...I suspect you are actually getting an Exception and not tracing the cause properly and then doing a sleep and then getting another Exception. Never ever catch an exception without tracing what it actually is somewhere.
Also I don't know what the sleep is supposed to be for. You will block in readByte() until something comes in, and that should be enough yielding for anybody. The sleep is just literally a waste of time. -
I make a SSL Server Socket. I want that a cell connect to it for take data. I have to make Certificate form my server. this is for a Stage so I can't pay for certificate. If I make my self signed cert can I install it to a cell or this operation is blocked?
Sorry, I make an SSL Server Socket using java and this server stays on a pc.
-
SSL Server socket: controlling the alias for the server certificate ?
Hi,
Could anyone please clear up the following ?
When you create an SSL server socket, it needs a certificate (to prove its identity), and for this it relies on a keystore:
System.setProperty("javax.net.ssl.keyStore", "c:/mystore");
My question is, what if the keystore contains several certificates ?
Eg:
keytool -import -alias AAA -file cert1.cer -keystore mystore
keytool -import -alias BBB -file cert2.cer -keystore mystore
Which certificate would the server use ?
And is there a way to control the alias it would use ?
Thanks :)This is a very good question and one that should be described in the Guide to Features. See javax.net.ssl.X509KeyManager.chooseServerAlias(). It does a search looking for aliases of a given key type, i.e. one of the ones the peer understands, & which are trusted by the peer. Any alias which the peer can accept will do.
-
JavaConsole Error: Problem reading data from server
HI All
We are getting this error on java console on a page:
Error: Problem reading data from Server - Java.Security.AccessControlException:access denied (java.util.PropertyPermission http.strictpostredirect Read)
In this page we are not firing a SQL Query of huge data.
Any suggestions on this why it is happening?
Thanks
ManishaManisha,
I think JVM(Java Virtual Machine) is trying to access something at network level and it cant able to find it.Or any new patches of java is installed.
Or may be due to IIS or Applet,Don't know exactly.
You can find some answers in below links:
http://java.sun.com/j2se/1.4.2/docs/api/java/security/AccessControlException.html
http://www.webdeveloper.com/forum/archive/index.php/t-46358.html
-Suresh -
Problem reading data from oracle database 11g using OleDbDataReader
Hi everyone I work with Visual Studio 2010 and C# programming language. I have a problem reading data from the oracle database. I created a WPF application with my main Window Xaml and class files and 1 more class called DataFiles. The thing I want is to read some data from the database on my grid in my WPF window. Problem is even though it connects to the database the grid is always empty. It isn't the connection string as I tested it and it connects to the database the problem seems to be in showing the LASTNAME (PREZIME in my native tongue) on the grid which is what it's supposed to do.
Here is the code:
Data Files Code
using System;
using System.Collections.ObjectModel;
using System.Data.SqlClient;
using System.Data.OleDb;
namespace SQLKonekcija
public class clsEmployee
public string Prezime { get; set; }
public class DataAccess
OleDbConnection oleCon;
OleDbCommand oleComd;
public DataAccess()
string connectionString = "provider=ORAOLEDB.ORACLE; data source=ORCL; password=****; user id=****;";
oleCon = new OleDbConnection(connectionString);
public ObservableCollection<clsEmployee> GetAllEmployee()
ObservableCollection<clsEmployee> EmpCol = new ObservableCollection<clsEmployee>();
oleComd = new OleDbCommand();
oleComd.Connection = oleCon;
oleComd.CommandText = "Select PREZIME from UPOSLENICI";
oleCon.Open();
OleDbDataReader Reader = oleComd.ExecuteReader();
Reader.Read();
while (Reader.Read())
EmpCol.Add(new clsEmployee()
Prezime = Reader["PREZIME"].ToString()
oleCon.Close();
return EmpCol;
}And here is my main window.cs code
public partial class MainWindow : Window
clsEmployee objEmpToAdd;
DataAccess objDs;
public MainWindow()
InitializeComponent();
private void Window_Loaded(object sender, RoutedEventArgs e)
objDs = new DataAccess();
dgEmp.ItemsSource = objDs.GetAllEmployee();And the XAML
<Window x:Class="SQLKonekcija.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded">
<Grid>
<DataGrid AutoGenerateColumns="False" Height="237"
HorizontalAlignment="Left" Margin="18,66,0,0" Name="dgEmp"
VerticalAlignment="Top" Width="466" ColumnWidth="*"
>
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding PREZIME}" Header="Prezime"></DataGridTextColumn>
</DataGrid.Columns>
</DataGrid>
<TextBlock Height="42" HorizontalAlignment="Left" Margin="18,15,0,0" Name="textBlock1" Text="TEST CONNECTION" VerticalAlignment="Top" Width="462" TextAlignment="Center" FontSize="28" FontWeight="ExtraBold" />
</Grid>
</Window>
The guys on the MSDN forums told me I should ask the question here so sorry if it's not your field.
Hope u guys can help, thanks.I tried it, commented out the reader.read and have the following connection string
string connectionString = "provider=ORAOLEDB.ORACLE; data source=ORCL; password=****; user id=****; OLEDB.NET=True"
Unfortunately the result is the same.
Edited by: Dino2dy on Nov 24, 2011 12:53 AM -
Socket Exception when closing Server Socket Streams if Client closes first
Hi
I have 2 processes - a Server socket and a client socket. If I close the Client process first, and then try closing down the Streams on the Server process, I get a SocketException with message "Socket is closed" when I try and close the 2nd Stream. It does not matter on the order of the Stream being closed down, the exception is always thrown when I try and close the second stream. The code snippets are below:
SERVER =======
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class ServerSocketTest {
public static void main(String args[]) {
try {
ServerSocket ss = new ServerSocket(9999);
Socket s = ss.accept();
// Get refs to streams...
InputStream is = s.getInputStream();
OutputStream os = s.getOutputStream();
// sleep to let client shutdown first...
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
System.err.println(e);
System.err.println("B4 inClose: isBound=" + s.isBound());
System.err.println("B4 inClose: isClosed=" + s.isClosed());
System.err.println("B4 inClose: isConnected=" + s.isConnected());
System.err.println("B4 inClose: isInputShutdown=" + s.isInputShutdown());
System.err.println("B4 inClose: isOutputShutdown=" + s.isOutputShutdown());
s.getInputStream().close();
System.err.println("After inClose: isBound=" + s.isBound());
System.err.println("After inClose: isClosed=" + s.isClosed());
System.err.println("After inClose: isConnected=" + s.isConnected());
System.err.println("After inClose: isInputShutdown=" + s.isInputShutdown());
System.err.println("After inClose: isOutputShutdown=" + s.isOutputShutdown());
s.getOutputStream().close(); // will break here with SocketException!
System.err.println("After outClose: isBound=" + s.isBound());
System.err.println("After outClose: isClosed=" + s.isClosed());
System.err.println("After outClose: isConnected=" + s.isConnected());
System.err.println("After outClose: isInputShutdown=" + s.isInputShutdown());
System.err.println("After outClose: isOutputShutdown=" + s.isOutputShutdown());
s.close();
} catch (Exception e) {
System.err.println(e);
CLIENT ======
import java.net.Socket;
public class ClientSocket {
public static void main(String args[]) {
try {
Socket s = new Socket("localhost", 9999);
try {
// sleep to leave connection up for a while...
Thread.sleep(2000);
} catch (InterruptedException e) {
System.err.println(e);
s.close();
} catch (Exception e) {
System.err.println(e);
The debug shows that isClosed() is set to 'true' after the first call to s.getInputStream().close(). The Sun API Socket class getOutputStream() has a call to isClosed() at the start of the method - it then throws the SocketException that I get. Why does the SocketImpl do this before I get a chance to call a.getOutputStream().close()?
One final thing, the calls to s.isInputShutdown() and s.isOuputShutdown always seem to return false even if the Streams have had their .close() method called.
Any ideas/help here greatly appreciated.
Thanks
GazOk, I know what's going on now - I needed something to do on Friday afternoon anyhow!
Basically if you call either getOutputStream.close() or getInputStream().close(), the underlying Sun implementation will close the Socket.
Here's what's happening under the covers in the Sun code:
s.getInputStream() is called on the Socket class.
The Socket class holds a reference to the SocketImpl class.
The SocketImpl class is abstract and forces sublclasses to extend it' s getInputStream() method.
The PlainSocketImpl extends SocketImpl.
PlainSocketImpl has a getInputStream() method that returns a SocketInputStream. When the stream is created for the first time, the PlainSocketImpl object is passed into the Constructor.
The SocketInputStream class has a close() method on it. The snippet of code below shows how the socket is closed:
<pre>
* Closes the stream.
private boolean closing = false;
public void close() throws IOException {
// Prevent recursion. See BugId 4484411
if (closing)
return;
closing = true;
if (socket != null) {
if (!socket.isClosed())
socket.close();
} else
impl.close();
closing = false;
</pre>
So, it seems that out PlainSocketImpl is getting closed for us, hence the SocketException being thrown in Socket.getOutputStream() when I call it after Socket.getInputStream()/
I've not had a look at the reason why the calls to s.isInputShutdown() and s.isOuputShutdown always seem to return false even if the Streams have had their .close() method called though - any thoughts appreciated.
Thanks
G -
Problem integrating weblogic commerce server; how to use dfc/jsp with only weblogic AS
"Hi,I was evaluating 4i WCM Edition Starter Kit. I have thefollowing one problem and one question.1. Problem:We installed Documentum (WCM Edition Starter Kit V4i)but BEA Integrationphase does not succeed.The error I got is "not enough disk space". We haveinstalled both BEA WLCS and WCM on D dive while documentum on C.Both drive currently has almost 1.5G free of hard disk spaceNow the content of BEAIntegrationins.txt is
What if you need to access more than one data source?
<sql:query var="myQuery" dataSource="myDataSource">
</sql:query>
<sql:query var="myOtherQuery" dataSource="myOtherDataSource">
</sql:query>
If you specify one data source as the default, how do you access the other
one?
-- Craig
"thanh nguyen" <[email protected]> wrote in message
news:3fa18529$[email protected]..
> I believe you can set up a default datasource for the application context
in the web.xml and weblogic.xml. That way, on your JSP, you will not need to
set the datasource. The connection pool will handle all of that for you.
>
> 1. modified weblogic.xml
> <reference-descriptor>
> <resource-description>
> <res-ref-name>jdbc/hr</res-ref-name>
> <jndi-name>jdbc/hr</jndi-name>
> </resource-description>
> </reference-descriptor>
> 2. modified web.xml
> <context-param>
> <param-name>javax.servlet.jsp.jstl.sql.dataSource</param-name>
> <param-value>jdbc/hr</param-value>
> </context-param>
>
> <resource-ref>
> <res-ref-name>jdbc/hr</res-ref-name>
> <res-type>javax.sql.DataSource</res-type>
> <res-auth>CONTAINER</res-auth>
> </resource-ref>
> 3. redeploy app
-
Server Socket does not read data input stream
Hi all,
I am very newbie to Java Network programming with sockets and multi-threading.
But I am obliged to develop a chat system written in Applets which can be placed on the website and used by visitors who come to my website.
In order to understand this, I have tested a basic web chat program I downloaded from the Internet which use sockets and multi-threadings. The program work fine, no bugs at all at both compilation and run time. I noticed that all three streams for Client side (i.e. first one is input stream used receiving data from User; the second one is socket input stream used for receiving data from Server socket, and the third is socket output stream used for writing data to server socket) were established. And the same, two socket streams (input & output) for Server side were also connected when running program giving right port number and IP address of the server.
The problem is both server and client sockets do not read data using the following stream classes:
1. DataStreamInput: I use input.readUTF() method
2. or BufferedReader: I use input.readLine() method
The example of the codes are below:
private BufferedReader input = null;
private PrintWriter output = null;
private Socket socket = null;
public void open() throws IOException
{ input = new BufferedReader(new
InputStreamReader(socket.getInputStream()));
System.out.println("Server socket input stream was created, and");
output = new PrintWriter(socket.getOutputStream());
System.out.println("Server socket output stream was created");
public void run()
{ System.out.println("Server Thread " + clientPort + " running.");
while (true)
{ try
System.out.println("Server is reading data from Client, wait...");
String fromClient = input.readLine();
System.out.println("Server received a message on " + clientPort + ".");
catch(IOException ioe)
{ System.out.println(clientPort + " ERROR reading: " + ioe.getMessage());
server.remove(clientPort);
stop();
The problem is at the line: String fromClient = input.readLine(); in the run() method? What is wrong with the codes above?
Note: I also try to use original codes which use readUTF() method in DataStreamInput class instead using readLine() in BufferedReader. Both methods dont read data from inputstream socket?
I very appreciate any help/advice from experienced developers.
Best regardsHi,
Yes. The readLine() method hangs! After the test, the execuation of the program is stopped at the line of readLine() method; it does not pass it?
There is no problem with writing to Server socket. After the test, the program pass through flush() method. Here is the code for writing to sever socket within ChatClient (client side socket) class:
private BufferedReader input = null;
private PrintWriter output = null;
public ChatClient(String serverName, int serverPort)
{ System.out.println("Establishing connection. Please wait ...");
try
{ socket = new Socket(serverName, serverPort);
System.out.println("Connected: " + socket);
start();
catch(UnknownHostException uhe)
{ System.out.println("Host unknown: " + uhe.getMessage()); }
catch(IOException ioe)
{ System.out.println("Unexpected exception: " + ioe.getMessage()); }
public void start() throws IOException
{ input = new BufferedReader (new
InputStreamReader(System.in));
System.out.println("Client User input stream was created,");
output = new PrintWriter(socket.getOutputStream());
System.out.println("Client Socket output stream was established, and");
if (thread == null)
{ client = new ChatClientThread(this, socket);
thread = new Thread(this);
thread.start();
public void run()
while (thread != null) {
String fromUser;
try{
while((fromUser = input.readLine())!= null)
System.out.println("Client wasreading a data from User, and");
output.println(fromUser);
output.flush();
System.out.println("Client has written a data to Server");
catch(IOException ioe)
{ System.out.println("Sending to server error: " + ioe.getMessage());
stop();
etc.
Here is a piece of codes for reading data from the Client Socket in the ChatServer Class (Server Side socket):
public void run()
{ System.out.println("Server Thread " + clientPort + " running.");
while (true)
{ try
{ //server.handle(clientPort, input.readLine());
System.out.println("Server is reading data from Client, wait...");
String fromUser = input.readLine();
//while((fromUser = input.readLine()) != null)
System.out.println("Server received a message on " + clientPort + ".");
catch(IOException ioe)
{ System.out.println(clientPort + " ERROR reading: " + ioe.getMessage());
server.remove(clientPort);
stop();
etc. Please advice why the readLine() method hangs; does not read data from the input stream received from the CLIENT? -
Error : There was a problem reading this document (109).
hello, i have a lot of PDF Files that become corrupted ! i dont know why
and i receive this error message when i open the pdf file:
" There was an error processing a page. There was a problem reading this document (109)."
im using adobe acrobat 8 prof. also acrobat reader.
please can any one help me to solve this big problem.When I encountered an error "there was a problem reading this document 110" in Acrobat Pro 11 on 28.7 MB CS6 file, it indeed was very frustrating.
I solved my problem, but since I don't know which step benefitted me, I've to enumerate all the steps I took:
Read below:
1.1. I could copy the file anywhere on the drive, but couldn't 'save as' from Acrobat Pro.
1.2. No document security was applied of any sort on the file.
1.3. Still in the first tab of the document properties, all details under advance section were empty. No 'PDF Version' 'location' 'file size' etc were populated. Nothing.
1.4. I couldn't change and save anything in any of property dialogue. I could comment on the text, but as soon as I tried to save, it gave an error (some sort of 'File reading' error).
1.5. When I tried to extract a page (I tried many), it gave 'reading error'.
1.6. I didn't try 'splitting error'. Since I was 100% sure, it'll give me same reading error.
1.7. I opened the file in Firefox and tried saving it as pdf from there. But no error, but no save either.
1.8. I ran 'Remove Hidden Information' from protection panel without any errors.
1.9. I tried 'sanitize document' from the same tab, but didn't succeed.
1.10. Then (here I think the problem was resolved), from Document Processing panel, I did some commands. 1st, 'Export all images', successfully. Then 'Remove all links', it found 0.
1.11. Then in 'print production' panel, I clicked/tried to open acrobat distiller. The same opened, did some processing. But I don't know if it did something in solving the problem or not.
1.12. Although I think my problem was resolved till now, but the last step I did was 'Saved As' the file (from the file menu) as a .ps file. Though I've not yet reopened/used that ps file (to convert it into a pdf file again). But around here I wanted to close the file and it asked me whether I wanted to save the file, I said yes. And it saved the file correctly. And I checked that in properties dialogue, the missing information was populated too.
1.13. Sorry for so lengthy instructions, but I had no choice. -
Two server sockets on the same machine, one not working.
Dear forum users.
I'm currently having a problem with running two server sockets on the same computer.
It gives no exceptions or anything, just that if i connect with another machine, the last serversocket that started,
will not accept connections..
Scenario:
Computer 1: Main server.
Computer 1: Game server.
Computer 2: Client
Computer 2 connects first to the main server (lets say port 13371)
Then connects to game server (port 6112).
Computer 2 failes to connect to the Game server for some reason.
But if i open a client at Computer 1, connects to main server, and then game server, it
works fine.
And if I put computer 2 as a Game server,
then everything works fine.
Working scenario:
Computer 1: Main server.
Computer 2: Game server
Computer 2: Client
Computer 1: Client
Now, however many that wants to connect to game server, works.
I have gone through the code 100 times now it feels like. And still dont see why this happends.
Anyone know if it is "working as intended"? Or just me doing something completely wrong that i cant see myself?
Sorry for not posting code, its too much code to post.Oh, sorry.
TCPServer:
protected ServerSocket serverSocket;
public abstract void processConnection(Socket client);
public void listen() {
try {
report("Listening to clients on port: " + portNumber);
while (serverSocket != null && acceptConnections) {
processConnection(serverSocket.accept());
report("Client accepted on serverSocket.");
} catch (SocketException e) {
report("TCPServer/listenForClients : SocketException.", e);
} catch (Exception e) {
report("TCPServer/listenForClients : Unknown Exception.", e);
cleanUp();
report("Stopped listening on port: " + portNumber);
}MainServer extends the TCPServer:
public void processConnection(Socket client) {
try {
MainServer_Client tmp = new MainServer_Client(client, this);
synchronized (clients) {
clients.add(tmp);
Thread th = new Thread(tmp);
th.start();
} catch (Exception e) {
report("MainServer/processConnection : Unknown Exception", e);
}GameServer extends TCPServer
public void processConnection(Socket client) {
try {
client.setTcpNoDelay(true);
GameServer_ServerClient tmp = new GameServer_ServerClient(client, this);
synchronized(clients) {
clients.add(tmp);
Thread th = new Thread(tmp);
th.start();
} catch(Exception e) {
report("GameServer_Host/processConnection : Unknown Exception",e);
e.printStackTrace();
}Edited by: Lgeee on Apr 30, 2010 2:57 AM -
SSL Server without Server Cert
The SSL specification http://wp.netscape.com/eng/ssl3/3-SPEC.HTM
Section 7.5 Handshake protocol overview
says
That Server Certificates are optional. Is it possible in JSSE to create a SSL Server Socket and start accepting clients without a Server Certificate ?.
Any samples/help appreciated.
regards
RajeshLook here:
http://forum.java.sun.com/thread.jsp?forum=2&thread=410373
Good luck!
Grant -
I upgraded to iOS 7 to my ipad using iTunes. When signing with the Apple ID I get an error reading "There was a problem connecting to the server" anyone who knows what to do next
Sounds more like you have a problem with your apple id. For starters go to that page click manage my apple id and singn in. If you can't sign in reset password.
https://appleid.apple.com
if you can sign in there, try to sign in to itunes on your computer.
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