Problems in read method
I have a method which run every 1 minutes to read data from other application. The read() method is used and it blocks until at least a byte is available. Some websites sugguest using thread.sleep + while....but if i use timer + timertask with the read() method....will it a bad coding?
Thanks
I'd use TimerTask/Timer. From the sounds of it scheduling is not this classes job - reading the data is.
Similar Messages
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Problem with "System.in.read()" read() method!
import java.io.*;
import java.lang.*;
class Count {
public static void main(String args[]) throws IOException
int count = 0;
while (System.in.read()!=-1)
count++;
System.out.println("Input has " + count + " chars.");
in this code the loop stucks and it increments the count variable infinitely of course as long as i hit enter. I am trying to understand the problem with read() method of system class's in object. in its definition it says; when the inputstream ends it returns -1, but in this code it does not return -1 ever. another question of mine is that what args[] array do? what does it store??Java doesn't bother much with the dos console and it a bit limited and limiting - no pretty colours /graphics options - just text - that's because java graduates to GUI's where there is laods of power and object /component support to do everything and everything you could imagine and more. System.in.read() ??? - thats a fine start!
what args[] array do? what does it store??
Good question !
It provides a means of passing a parameter argument from the command line to the program - consider this;-public class HelloWithArgs {
public static void main(String[] args) {
System.out.println("Hello I am " + args[0]);
}What does it do and how does it work? Or this;-public class HelloWithArgs2 {
public static void main(String[] args) {
try{
String myName = args[0];
catch(ArrayIndexOutOfBoundsException aob){
System.out.print("No names: program will end");
System.exit(0);
System.out.println("Hello I am " + myName);
}Study them and have fun. Though to answer the question -
" public static void main(String[] args) {" // or
" public static void main(String[] parameters) {"
is the 'entry point' of all java programs, in order to do something it has to have a main() method and if youre going to pass on parameters, then why not a String array? If you think about it anything else would be fairly useless. -
Problem with using read() method of BufferedInputStream
Hi,
I m using BufferedInputStream for reading from a socket and I m using read() method for getting data character by character from it . It runs successfully for sometime and then blocks indefinitely and hangs the application. Maybe , when it does not find any data to be read from socket or the LAN connection is broken, it keeps on trying and blocks further processing.
Is there any way to solve this problem so that it does not hangs the application and comes out gracefully ?
Thanx and regards,
Aartee GoyalMost read-methods are blocking, if there is nothing to read.
If you don't want, that your application is blocking, too, the read method has to run in a thread.
The second possibility is, to ask, whether there is something to read
BufferedInputStream bis = ...
if (bis.available() > 0) {
int b = bis.read();
else {
// sleep or break or ???
} -
i am facing problem while reading values from properties file ...i am getting null pointer exception earlier i was using jdeveloper10g now i am using 11g
hi TimoHahn,
i am getting following exception in JDeveloper(11g release 2) Studio Edition Version 11.1.2.4.0 but it works perfectly fine in JDeveloper 10.1.2.1.0
Root cause of ServletException.
java.lang.NullPointerException
at java.util.PropertyResourceBundle.handleGetObject(PropertyResourceBundle.java:136)
at java.util.ResourceBundle.getObject(ResourceBundle.java:368)
at java.util.ResourceBundle.getString(ResourceBundle.java:334)
at org.rbi.cefa.master.actionclass.UserAction.execute(UserAction.java:163)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:300)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at oracle.security.jps.ee.http.JpsAbsFilter$1.run(JpsAbsFilter.java:119)
at java.security.AccessController.doPrivileged(Native Method)
at oracle.security.jps.util.JpsSubject.doAsPrivileged(JpsSubject.java:315)
at oracle.security.jps.ee.util.JpsPlatformUtil.runJaasMode(JpsPlatformUtil.java:442)
at oracle.security.jps.ee.http.JpsAbsFilter.runJaasMode(JpsAbsFilter.java:103)
at oracle.security.jps.ee.http.JpsAbsFilter.doFilter(JpsAbsFilter.java:171)
at oracle.security.jps.ee.http.JpsFilter.doFilter(JpsFilter.java:71)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at oracle.dms.servlet.DMSServletFilter.doFilter(DMSServletFilter.java:139)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3715)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3681)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2277)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2183)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1454)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:178) -
Problem on reading and writing from from a *.txt file
I get Problem on reading and writing from from a *.txt file. The following is the read() method...
The software said the DataInputStream is depreciated. Can anyone help me please?
public void read()
File file = new File("C://Documents and Settings//Charles//My Documents//Brunel//EE2065//Assignment and Lab//Assignment 4 and Lab 4//data.txt");
FileInputStream in = null;
String str = "";
try
in = new BufferedReader(file);
//in = new FileInputStream(file);
for(;;)
str = new BufferedReader(in).readLine();
//str = new DataInputStream(in).readLine();
if(str == null)
break;
System.out.print(str);
in.close();
catch(IOException e)
System.err.println("execution error: " +e);
}Thank you for your reply. I have made some change. However, there is an incompetable type found error.
in = new BufferedReader(new InputStreamReader(in));The following are all of the code.
public void read()
File file = new File("C://Documents and Settings//Charles//My Documents//Brunel//EE2065//Assignment and Lab//Assignment 4 and Lab 4//data.txt");
FileInputStream in = null;
//BufferedReader in = null;
String str = "";
try
in = new BufferedReader(new InputStreamReader(in));
//in = new FileInputStream(file);
for(;;)
BufferedReader Bstr = new BufferedReader(new InputStreamReader(in));
//str = new BufferedReader(in).readLine();
//str = new DataInputStream(in).readLine();
if(str == null)
break;
System.out.print(str);
in.close();
catch(IOException e)
System.err.println("execution error: " +e); -
Question about read method of InputStream
Hello everyone,
I am using read method of InputStream to read a stream from a remote machine. The network connection is not very stable (for example, a wireless network whose the signal strength is relatively low). I am wondering if read method returns -1 (which indicates the end of the stream has been reached), and if I invoke read method again on the same stream, is it possible to read any more data?
I think maybe I can read some more data even if read returns -1 in one time because the connection is not very stable. I am looking for your comments to my problem in my specific situation.
regards,
GeorgeThanks Adeodatus,
Doc says This method blocks until input data is
available, the end of the stream is detected, or
an
exception is thrown.
http://java.sun.com/j2se/1.4.2/docs/api/java/io/InputS
tream.html#read()
I have not found any related parts in documents.
http://java.sun.com/j2se/1.4.2/docs/api/
Them's docs.
if you're using a different version of java, replace
the underlined portion with your version number.I am using JDK 1.3, and I have found related documents. But I can not find out where can I set timeout value of read operation. I am reading data from an HTTP InputStream. Can you help?
regards,
George -
Indesign CS3-JS - Problem in reading text from a text file
Can anyone help me...
I have an problem with reading text from an txt file. By "readln" methot I can read only the first line of the text, is there any method to read the consecutive lines from the text file.
Currently I am using Indesign CS3 with Java Script (for PC).
My Java Script is as follows........
var myNewLinksFile = myFindFile("/Links/NewLinks.txt")
var myNewLinks = File(myNewLinksFile);
var a = myNewLinks.open("r", undefined, undefined);
myLine = myNewLinks.readln();
alert(myLine);
function myFindFile(myFilePath){
var myScriptFile = myGetScriptPath();
var myScriptFile = File(myScriptFile);
var myScriptFolder = myScriptFile.path;
myFilePath = myScriptFolder + myFilePath;
if(File(myFilePath).exists == false){
//Display a dialog.
myFilePath = File.openDialog("Choose the file containing your find/change list");
return myFilePath;
function myGetScriptPath(){
try{
myFile = app.activeScript;
catch(myError){
myFile = myError.fileName;
return myFile;
Thanks,
Bharath Raja GHi Bharath Raja G,
If you want to use readln, you'll have to iterate. I don't see a for loop in your example, so you're not iterating. To see how it works, take a closer look at FindChangeByList.jsx--you'll see that that script iterates to read the text file line by line (until it reaches the end of the file).
Thanks,
Ole -
Problem in Reading XLSX File (MS EXCEL 2007).
Dear All ,
I am reading all the properties to XL sheet and then utilising it in my code .
I am getting some problem in reading the Border of the Cell , my code is working fine with most of the Excel Sheet but it can not correctly read the Border of a few Excel files.
I am using the method ,
getBorderBottomEnum()
or
getBorderBottom()
but I can not read the Border used correctly for all the Excel Sheet .
Please Help.
Please revert if I am not clear.
Thanking You All.I'm guessing that your question is about Apache POI. They don't have a forum AFAIK, but they do have a [url http://poi.apache.org/mailinglists.html]mailing list.
John -
Problem in reading properties in webapp
Hi,
i've a problem in reading properies from resource ...
My actions are next:
InputStream is = this.getClass().getResourceAsStream("/some.properties");
// in a static case, i simply create an instance of the class.
InputStream is = this.getClass().getClassLoader().getResourceAsStream("some.properties");
property file is allocated in web-inf/classes
and also in app-inf/classes - because web-app is a part of ear.
Both methods does work in tomcat ... - in single web app
Are any suggestions?emmm ... however .. it is my bug :) ...
it does work ... however in another place process of reading proeprty goes through SystemResource... -
Encoding problem while reading binary data from MQ-series
Dear all,
we are running on 7.0 and we have an encoding problem while reading binary data from MQ-series. Because we are getting flat strings from queue we use module "Plain2ML" (MessageTransformBean) for wrapping xml-elements around the incoming data.
The MQ-Series-Server is using CCSID 850, which we configured in connection parameters in communication channel (both parameters for Queuemanager CCSID and also CCSID of target).If there are special characters in the message (which HEX-values differ from codepage to codepage) we get errors in our adapter while executing, please see stack-trace for further analysis below.
It seems to us that
1. method ByteToCharUTF8.convert() expects UTF-8 in binary data
2. Both CCSID parameters are not used anyway in JMS-adapter
How can we solve this problem without changing anything on MQ-site?
Here is the stack-trace:
Catching com.sap.aii.af.mp.module.ModuleException: Transform: failed to execute the transformation: com.sap.aii.messaging.adapter.trans.TransformException: Error converting Message: 'sun.io.MalformedInputException'; nested exception caused by: sun.io.MalformedInputException caused by: com.sap.aii.messaging.adapter.trans.TransformException: Error converting Message: 'sun.io.MalformedInputException'; nested exception caused by: sun.io.MalformedInputException
at com.sap.aii.af.modules.trans.MessageTransformBean.throwModuleException(MessageTransformBean.java:453)
at com.sap.aii.af.modules.trans.MessageTransformBean.process(MessageTransformBean.java:387)
at com.sap.aii.af.mp.module.ModuleLocalLocalObjectImpl0_0.process(ModuleLocalLocalObjectImpl0_0.java:103)
at com.sap.aii.af.mp.ejb.ModuleProcessorBean.process(ModuleProcessorBean.java:292)
at com.sap.aii.af.mp.processor.ModuleProcessorLocalLocalObjectImpl0_0.process(ModuleProcessorLocalLocalObjectImpl0_0.java:103)
at com.sap.aii.adapter.jms.core.channel.filter.SendToModuleProcessorFilter.filter(SendToModuleProcessorFilter.java:84)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.ConvertBinaryToXiMessageFilter.filter(ConvertBinaryToXiMessageFilter.java:304)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.ConvertJmsMessageToBinaryFilter.filter(ConvertJmsMessageToBinaryFilter.java:112)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.InboundDuplicateCheckFilter.filter(InboundDuplicateCheckFilter.java:87)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.TxManagerFilter.filterSend(TxManagerFilter.java:123)
at com.sap.aii.adapter.jms.core.channel.filter.TxManagerFilter.filter(TxManagerFilter.java:59)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.DynamicConfigurationFilter.filter(DynamicConfigurationFilter.java:72)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.PmiAgentFilter.filter(PmiAgentFilter.java:66)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.InboundCorrelationFilter.filter(InboundCorrelationFilter.java:60)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.JmsHeadersProfileFilter.filter(JmsHeadersProfileFilter.java:59)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.MessageInvocationsFilter.filter(MessageInvocationsFilter.java:89)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.JarmMonitorFilter.filter(JarmMonitorFilter.java:57)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.filter.ThreadNamingFilter.filter(ThreadNamingFilter.java:62)
at com.sap.aii.adapter.jms.core.channel.filter.MessageFilterContextImpl.callNext(MessageFilterContextImpl.java:195)
at com.sap.aii.adapter.jms.core.channel.SenderChannelImpl.doReceive(SenderChannelImpl.java:263)
at com.sap.aii.adapter.jms.core.channel.ChannelImpl.receive(ChannelImpl.java:437)
at com.sap.aii.adapter.jms.core.connector.MessageListenerImpl.onMessage(MessageListenerImpl.java:36)
at com.ibm.mq.jms.MQMessageConsumer$FacadeMessageListener.onMessage(MQMessageConsumer.java:399)
at com.ibm.msg.client.jms.internal.JmsMessageConsumerImpl$JmsProviderMessageListener.onMessage(JmsMessageConsumerImpl.java:904)
at com.ibm.msg.client.wmq.v6.jms.internal.MQMessageConsumer.receiveAsync(MQMessageConsumer.java:4249)
at com.ibm.msg.client.wmq.v6.jms.internal.SessionAsyncHelper.run(SessionAsyncHelper.java:537)
at java.lang.Thread.run(Thread.java:770)
Caused by: com.sap.aii.messaging.adapter.trans.TransformException: Error converting Message: 'sun.io.MalformedInputException'; nested exception caused by: sun.io.MalformedInputException
at com.sap.aii.messaging.adapter.Conversion.service(Conversion.java:714)
at com.sap.aii.af.modules.trans.MessageTransformBean.processTransform(MessageTransformBean.java:538)
at com.sap.aii.af.modules.trans.MessageTransformBean.processTransform(MessageTransformBean.java:528)
at com.sap.aii.af.modules.trans.MessageTransformBean.processTransform(MessageTransformBean.java:471)
at com.sap.aii.af.modules.trans.MessageTransformBean.process(MessageTransformBean.java:364)
... 36 more
Caused by: sun.io.MalformedInputException
at sun.io.ByteToCharUTF8.convert(ByteToCharUTF8.java:270)
at sun.nio.cs.StreamDecoder$ConverterSD.convertInto(StreamDecoder.java:287)
at sun.nio.cs.StreamDecoder$ConverterSD.implRead(StreamDecoder.java:337)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:223)
at java.io.InputStreamReader.read(InputStreamReader.java:208)
at java.io.BufferedReader.fill(BufferedReader.java:153)
at java.io.BufferedReader.readLine(BufferedReader.java:316)
at java.io.LineNumberReader.readLine(LineNumberReader.java:176)
at com.sap.aii.messaging.adapter.Conversion.convertPlain2XML(Conversion.java:310)
at com.sap.aii.messaging.adapter.Conversion.service(Conversion.java:709)
... 40 more
Any ideas?
Kind regards, StefanHi Stefan,
for the first MTB now we are using only one parameter: Transform.ContentType = text/plain;charset="ISO-8859-1"
The second MTB, which does the XML-Wrapping, is configured like this:
Transform.Class = com.sap.aii.messaging.adapter.Conversion
Transform.ContentType = application/xml
xml.conversionType = SimplePlain2XML
xml.fieldNames = value
xml.fieldSeparator = §%zulu§%
xml.processFieldNames = fromConfiguration
xml.structureTitle = payload
Both CCSID configuration parameters from the "Source"-Tab we've set to 850.
Now, we don't get an error anymore - sun.io.malformedInputException - , but, unfortunately, now special character conversion succeeded (we need an "ß" and we get an ISO-HEX-E1 -> á). E1 is (different from ISO) an "ß" in 850.
Any ideas? -
I have problem with pay method
I have problem with pay method. My card declined. I change card and I have the same problem. What can i do? Why declined my card again?
Contact iTunes store support: https://ssl.apple.com/emea/support/itunes/contact.html.
-
Hi, I am having this problem:
I made a CustomItem, a TextField, now I overloaded the traverse method, so if the keycode is Canvas.UP or Canvas.DOWN then return false else return true.
The problem is that when I press the left or rigth button it also returns false and not true.
and there is another problem with traverse, before returning false or true I set a boolean and call to repaint to draw it on some way if its selected or not, the paint method is being called but it just dont draw as desired.
protected void paint(Graphics g, int ancho, int alto) {
System.out.println ("Dentro del paint, seleccionado="+seleccionado);
try {
g.drawString(label, 0, 0, Graphics.TOP|Graphics.LEFT);
if (!seleccionado) {
g.setColor(120, 120, 120);
g.drawRect(0, 4, tama�oTexto+8, 25);
if (seleccionado) {
g.setColor(255, 255, 255);
g.fillRect(1, 5, (tama�oTexto+8-1), 23);
g.setColor(0, 0, 0);
if (!seleccionado) {
g.setColor(80, 80, 80);
g.drawString(texto, 4, 7, Graphics.TOP|Graphics.LEFT);
if (seleccionado) {
int cursorX=Font.getDefaultFont().charsWidth((texto.substring(0, idLetraActual)).toCharArray(), 0, texto.substring(0, idLetraActual).length())+4;
g.drawChar('|', cursorX, 7, Graphics.TOP|Graphics.LEFT);
} catch (Exception E){
E.printStackTrace();
}the traverse method set the seleccionado variable and calls to repaint but instead of being false the paint method is drawing it as true (most of times).I have a problem with findByxxx() method.. in
Container managed bean.
i have
Collection collection =
home.findByOwnerName("fieldValue");
specified in my Client Program, where ownerName is the
cmp fieldname..
and
public Collection findByOwnerName(String ownerName)
throws RemoteException, FinderException
defined in my home interface.
i have not mentioned the findBy() method anywhere else
(Bean class). You have to describe the query in the deployment descriptor.
>
Even if i have a same "fieldValue" in the database
(Oracle), which i specified in findBy() method, iam a
result of owner Not found, which is not the case as i
have that owner name.
for the same application if i use findByPrimaryKey(),
it is working..
Can any one please post me the solution. -
Problem with Vector method addElement
I am new to Java. I am using JDK 1.3. I am writing a program that will convert a text file to a binary file that stores a Vector object. I have narrowed my problem to the method that reads the text file and creates my vector. Each element in my vector stores an integer and a string variable. The reading of the text file works find and the creation of my record works find. It seems that the storing of the record in the vector is not working. When I print the first 10 elements of the vector, it have the same record(the last record of my text file). What is wrong with the method below? I am also appending the result of running my program.
private static void readTextFile(File f) {
try {
FileReader fileIn = new FileReader(f);
BufferedReader in = new BufferedReader(fileIn);
String line;
int i;
SsnLocationRecord recordIn = new SsnLocationRecord();
int ctr = 0;
while (true) {
line = in.readLine();
if (line == null)
break;
ctr += 1;
i = line.indexOf(" ");
recordIn.putAreaNumber(Integer.parseInt(line.substring(0,i).trim()));
recordIn.putLocation(line.substring(i+1).trim());
records.addElement(recordIn);
if (ctr < 11)
System.out.println(recordIn);
in.close();
} catch (IOException e) {
System.out.println ("Error reading file");
System.exit(0);
for (int i = 0; i < 11; i++)
System.out.println((SsnLocationRecord) records.elementAt(i));
RESULTS:
C:\Training\Java>java ConvertTextFileToObjectFile data\ssn.dat
0 null
3 New Hampshire
7 Maine
9 Vermont
34 Massachusetts
39 Rhode Island
49 Connecticut
134 New York
158 New Jersey
211 Pennsylvania
680 Nevada
680 Nevada
680 Nevada
680 Nevada
680 Nevada
680 Nevada
680 Nevada
680 Nevada
680 Nevada
680 Nevada
680 Nevada
C:\Training\Java>First of all it would be better if you did a priming read and then checked line == null in the while statement instead of the way you have it.
ctr++ will also accomplish what ctr +=1 is doing.
you need to create a new instance of SsnLocationRecord for each line read. What you are doing is overlaying the objects data each time you execute the .putxxxx methods. The reference to the object is placed in the vector. The actual object is still being updated by the .putxxx methods (NOTE : THIS IS THE ANSWER TO YOUR MAIN QUESTION).
you close should be in a finally statement.
To process through all the elements of a Vector create an Enumeration and then use the nextElement() method instead of the elementAt is probably better. (Some will argue with me on this I am sure).
Also, on a catch do not call System.exit(0). This will end your JVM normally. Instead throw an Exception (Runtime or Error level if you want an abnormal end). -
Hello, I'm new in java development, and I'm french with a student English, sorry if that I say is strange is the expressions.
I have a problem with network streams and serialization.
I want to establish a connection between 2 apps, on 2 different computers. For the development, the tests are local (IP : 127.0.0.1)
The problem : I send 4 bytes and I flush after, and I receive 6 bytes. To know what is transmitting on the connection, I override the OutputStream class.
I think that the flush() method produces 2 bytes but i don't think how.
I put you the codes follow :
Thanks for any help.
The sender function :
// This function is called when the user want to send data to another user.
// This piece of function establishing the connection between 2 users.
public int startListeningForNFT(String senderUserName, int indexOfSender) {
System.out.println(senderUserName + " demande à " + this.userName + " de démarrer la procédure de réception.");
/* Cette fonction est l'interface ente le serveur et le client2,
* elle retourne le port et l'IP que le client2 le lui a renvoyé. */
/* This function send an Integer which will trig a reception function in the receiver
This function is called in a Thread. */
try {
this.oos.writeObject(44);
this.oos.flush();
System.out.println("On a bien envoyé OBJ2AskerInfos sur le port " + portToListen);
byte b = this.ois.readByte();
System.out.println("Byte = " + b);
b = this.ois.readByte();
System.out.println("Byte = " + b);
b = this.ois.readByte();
System.out.println("Byte = " + b);
b = this.ois.readByte();
System.out.println("Byte = " + b);
b = this.ois.readByte();
System.out.println("Byte = " + b);
catch (IOException e) { e.printStackTrace(); }
return Constantes.PORT_DATA;
}The receiver function :
public class ClientClient implements WindowClient {
// This 3 attributes are initalized correctly.
private Socket comSocket;
private String comPort;
private String userName;
public ClientClient() {
try {
comSocket = new Socket(ipToJoin, Integer.parseInt(comPort));
oos = new ObjectOutputStream(new DebugOutputStream(comSocket.getOutputStream()));
ois = new ObjectInputStream(comSocket.getInputStream());
oos.writeObject(userName);
oos.flush();
ThreadInputListener til = new ThreadInputListener();
til.start();
catch (UnknownHostException e) { e.printStackTrace(); }
catch (ClassNotFoundException e) { e.printStackTrace(); }
catch (IOException e) {
e.printStackTrace();
JOptionPane.showMessageDialog(null, ("Auncun serveur n'a été trouvé sur l'adresse indiquée :\n" + ipToJoin), "Erreur", JOptionPane.ERROR_MESSAGE);
public class ThreadInputListener extends Thread {
@SuppressWarnings("unchecked")
public void run() {
try {
while(true) {
Object receivedObject = ois.readObject();
// Si l'objet reçu est un OBJ2InfosOnAsker => Renvoyer le port.
// If received Object is an integer
if(receivedObject instanceof Integer) {
System.out.println(userName +" a bien reçu l'objet OBJ2InfosOnAsker...");
System.out.println(userName +" a bien reçu int." + receivedObject);
System.out.println("On lance les 4 int :");
// Send 4 bytes to the sender (control bytes, just for solve the problem)
oos.writeByte(7);
oos.writeByte(8);
oos.writeByte(9);
oos.writeByte(10);
oos.flush();
System.out.println("...et a bien envoyé le port");
catch (IOException e) {
// ArrayList<HostClient> temp = new ArrayList<HostClient>();
// temp.add(new HostFictiveClient(userName));
// fenetreprincipale.updateClientList(temp);
fenetreprincipale.addDiscution("Vous avez été déconnecté du serveur.");
catch (ClassNotFoundException e) { e.printStackTrace(); }
}The override function of OutputStream :
public class DebugOutputStream extends OutputStream {
private OutputStream os;
public DebugOutputStream(OutputStream os) {
super();
this.os = os;
@Override
public void write(int b) throws IOException {
System.out.println("ClientClient envoie " + b + " soit " + ((char)b));
os.write(b);
}The sender function says :
Host demande à User1 de démarrer la procédure de réception.
On a bien envoyé OBJ2AskerInfos sur le port 3001
Byte = 4
Byte = 0
Byte = 7
Byte = 8
Byte = 9And the receiver function says :
User1 a bien reçu l'objet OBJ2InfosOnAsker...
User1 a bien reçu int.44
On lance les 7 int :
ClientCLient envoie 119 soit w //
ClientCLient envoie 4 soit // Both of this lines are stranges
ClientCLient envoie 7 soit
ClientCLient envoie 8 soit
ClientCLient envoie 9 soit
ClientCLient envoie 10 soit
...et a bien envoyé le portMinimus wrote:
Ok, but this layer has maid just to print in the eclipse console the bytes written on the stream, With or without this function, the flush() operation generate 2 bytes, I don't know why.
When I want to send manually the byte '7', the result of both lines :
oos.writeByte(7);
oos.flush();is that my writeByte and my flush send 3 bytes :
Byte val = 119 charcode = w
Byte val = 1 charcode =
Byte val = 7 charcode =
Only the 'Byte val = 7 charcode = ' line is good.
Why the flush generate 2 unknown bytes at this code position ?Actually, it's (might be) writing more than two bytes. Run this:
public class OOSTest {
public static void main(String[] args) throws Throwable {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeByte(7);
oos.close();
byte[] bytes = baos.toByteArray();
System.out.println(Arrays.toString(bytes));
//prints "[-84, -19, 0, 5, 119, 1, 7]"
}The explanation is in the Javadoc for ObjectOutputStream:
Primitive data, excluding serializable fields and externalizable data, is written to the ObjectOutputStream in block-data records. A block data record is composed of a header and data. The block data header consists of a marker and the number of bytes to follow the header. OOSs should only be used when the OIS is being used properly on the other end. If you don't want this header, use a DataOutputStream. Is there an actual problem or are you just confused about the extra bytes? If there is a problem in reading, my guess is that you're somehow not reading from your OIS symmetrically with your OOS. Can you post a complete, compilable example that demonstrates the behaviour? There's obviously an issue somewhere, I just haven't spotted it yet.
If there wasn't an actual problem in reading, well: there's your explanation.
Edited by: endasil on 26-Oct-2009 10:55 AM -
Problem with affinetransformOp method...
I have a serious problem with filter method
I Want to make a image flipping or some other filtering by using
AffineTransformOp
but it printouts an erro like this
cannot resolve symbol
op.filter (img, flipped)
(the error pointer shows ".after the op")
a code from my one of the filters
BufferedImage flipped = new BufferedImage(img.getHeight(), img.getWidth(),BufferedImage.TYPE_INT_RGB);
AffineTransform trans = new AffineTransform(0, 1, 1, 0, 0, 0);
AffineTransformOp op = new AffineTransformOp(trans, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);
op.filter(img, flipped); //img is my buffered image source
I used some other ways like (img, null) but always give out error.
thanks..Did you declare "img" as BufferedImage or something else?
What is the full error message?
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