Writing to a file using DataOutputStream

the goal is to write an object named cd1 to a file data.dat using a method writeData.
writeData is defined as:
void writeData(DataOutputStream out), which writes an object, field y field to a DataOutputStream. (plus some other blah blah).
so here's what I have so far (only pieces of code are posted)
File dataFile = new File(ioDir, "data.dat");
               dataFile.createNewFile();
               DataOutputStream out1 = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(dataFile)));
               cd1.writeData(out1);
     public void writeData(DataOutputStream out) {
          iWritten = true;
          try {
               out.writeInt(iNumTracks);
               out.writeBoolean(iWritten);
               out.close();
          } catch (IOException xcp) {
               System.out.println(xcp);
     }but when I open the file data.dat it seems to be totally empty, doesn't seem like anything gets written to it.

have to check the file size ?
the data you write to the file maybe not displayable on screen. example, all character/byte < 32

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Writing to a file using log4j

Hi ,
I am facing an issue in rolling out file on an hourly basis. I have a source file , say usagelog_date.log which records logging, then after an hour an hour I have to separate that file , give it a different name say usagelog_date.10.log , I copy the contents of the source file into the rolling file, and make that source file empty. But after making that file empty when I am writing to the file using some threads simultaneously, I get some blank characters first and only after that the logging starts, that increases the file size to a large extent.
My java code which does this separation is as follows.
package com.proquest.services.usage.helper;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.nio.channels.FileLock;
import java.util.Calendar;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class UsageRotator {
     private Log scpLog = LogFactory.getLog("SCPLog");
     public String rotateAndReturnFilename(String rotationdate, String location) throws Exception {
          Calendar calendar = Calendar.getInstance();
          int hour_of_day = calendar.get(Calendar.HOUR_OF_DAY);
          String rotationalTime = ((hour_of_day < 10) == true) ? "0" + hour_of_day : "" + hour_of_day;
          String rotatedFileName = null;
          File usageLoggingLogFile = new File(location + "usagelogging." + rotationdate + ".log");
          if (usageLoggingLogFile != null && usageLoggingLogFile.exists()) {
               File usageLoggingRotatedFile = new File(location + "usagelogging." + rotationdate + "." + rotationalTime + ".log");
               copyFile(usageLoggingLogFile, usageLoggingRotatedFile);
//copying the contents of source file to a rolling file
               FileOutputStream fout = new FileOutputStream();
// making the source file empty fout.flush();
               usageLoggingLogFile.setWritable(true);
               boolean isEmpty = isFileEmpty(usageLoggingLogFile);
               if(isEmpty)
                    scpLog.info("Existing file has been empty so it's good to proceed for looging next occurances");
               rotatedFileName = usageLoggingRotatedFile.getName();
               scpLog.info("Log file has been rotated to "+rotatedFileName);
          } else {
               throw new Exception("File rotation failed : UsageLogging file couldn't be found for the supplied date");
          return rotatedFileName;
     private void copyFile(File source, File destn) throws Exception {
          FileInputStream fis = new FileInputStream(source);
     FileOutputStream fos = new FileOutputStream(destn);
     try {
     byte[] buf = new byte[1024];
     int i = 0;
     while ((i = fis.read(buf)) != -1) {
     fos.write(buf, 0, i);
     catch (FileNotFoundException e) {
     throw new Exception("[ERROR] File copy failed");
     finally {
     if (fis != null) fis.close();
     if (fos != null) fos.close();
     private boolean isFileEmpty(File file) throws Exception {
          FileReader fr = new FileReader(file);
          BufferedReader br = new BufferedReader(fr);
          boolean isEmpty = true;
          while (br.readLine() != null) {
               isEmpty = false;
          return isEmpty;
And my log4j file with which I am writing is
# Default is to send information messages and above to the console
log4j.rootLogger = DEBUG, DailyLogFileAppender
# Logger configurations
#log4j.logger.com.proquest.services.usage=DEBUG, DailyLogFileAppender
log4j.logger.com.proquest.services.UsageLog=INFO, UsageLogFileAppender
# Appender configurations
# Define an appender which writes to a file which is rolled over daily
log4j.appender.DailyLogFileAppender = com.proquest.services.log.PqDailyRollingFileAppenderExt
log4j.appender.DailyLogFileAppender.File = logs/usagelogging/usagelogging-error.log
log4j.appender.DailyLogFileAppender.DatePattern = '.'yyyy-MM-dd
log4j.appender.DailyLogFileAppender.Append = true
log4j.appender.DailyLogFileAppender.layout = org.apache.log4j.PatternLayout
log4j.appender.DailyLogFileAppender.layout.ConversionPattern=%d{ISO8601} %m%n
log4j.additivity.com.proquest.services.usage = false
log4j.additivity.com.proquest.services.UsageLog = false
log4j.appender.UsageLogFileAppender = com.proquest.services.log.PqDailyRollingFileAppenderExt
log4j.appender.UsageLogFileAppender.File = logs/usagelogging/usagelogging.log
log4j.appender.UsageLogFileAppender.DatePattern = '.'yyyy-MM-dd
log4j.appender.UsageLogFileAppender.Append = true
log4j.appender.UsageLogFileAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.UsageLogFileAppender.layout.ConversionPattern=%d{ISO8601} %m%n
Can somebody please suggest me what to do, as I have been badly deadlocked into the problem.
Thanks
Suman

neoghy wrote:
... rolling out file on an hourly basis.
And my log4j file with which I am writing is
# Default is to send information messages and above to the console
log4j.rootLogger = DEBUG, DailyLogFileAppender
# Logger configurations
#log4j.logger.com.proquest.services.usage=DEBUG, DailyLogFileAppender
log4j.logger.com.proquest.services.UsageLog=INFO, UsageLogFileAppender
# Appender configurations
# Define an appender which writes to a file which is rolled over daily
log4j.appender.DailyLogFileAppender = com.proquest.services.log.PqDailyRollingFileAppenderExt
log4j.appender.DailyLogFileAppender.File = logs/usagelogging/usagelogging-error.log
log4j.appender.DailyLogFileAppender.DatePattern = '.'yyyy-MM-dd
log4j.appender.DailyLogFileAppender.Append = true
log4j.appender.DailyLogFileAppender.layout = org.apache.log4j.PatternLayout
log4j.appender.DailyLogFileAppender.layout.ConversionPattern=%d{ISO8601} %m%n
log4j.additivity.com.proquest.services.usage = false
log4j.additivity.com.proquest.services.UsageLog = false
log4j.appender.UsageLogFileAppender = com.proquest.services.log.PqDailyRollingFileAppenderExt
log4j.appender.UsageLogFileAppender.File = logs/usagelogging/usagelogging.log
log4j.appender.UsageLogFileAppender.DatePattern = '.'yyyy-MM-dd
log4j.appender.UsageLogFileAppender.Append = true
log4j.appender.UsageLogFileAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.UsageLogFileAppender.layout.ConversionPattern=%d{ISO8601} %m%nCan somebody please suggest me what to do, as I have been badly deadlocked into the problem.I assume you mean [DailyRollingFileAppender ^apache^|http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/DailyRollingFileAppender.html]
log4j.appender.DailyRollingFileAppender.DatePattern = '.'yyyy-MM-dd-HH

Writing into Excel file using PL/SQL and formatting the excel file

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I was trying to write nos. from 1 to 8 into a text file using the below program.
process
type IntegerFileType is file of integer;
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hello,
so i wrote this vi to write some data to a text file and that part works correctly.
the problem i'm having is that, it doesn't append to the file. so for each data point that it writes it requires a new file.
in otherwords, if i need to write 10 data points the program prompts each time for 10 different file names.
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Attachments:
Untitled 7.vi ‏75 KB
Untitled 7.JPG ‏99 KB

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import javax.servlet.http.*;
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Yes, in fact what I want is the file to be in the server, now, I modificated my code to the following:
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
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writer.write("<tlf>" + cadenanumero + "</tlf>");
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Writing to remote files using an applet.

I programmed a basic game as an applet for a web site, but it really needs some kind of high score functionality.
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package MyTest;
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Is there anyway I can write correct data into a file?
My output needs to be a readable text format file.
Can anyone help please?

obj1.writeExternal(oOut);This should be
oOut.writeObject(obj1);However,
The output I get in test.bin contains some junk ascii
codes. The only item that is written correctly in the
file is the string.If you don't want 'junk' don't use Externalizable and ObjectOutputStream at all, just use PrintStream/PrintWriter.println().

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