I/O / Streams :: How To Read In A Binary File Correctly
Nov 8, 2014
I have a binary file that has identifiers for the start of each record
You can see here that the record starts with 00 00 and the next record starts with 00 00 etc...
How do I read between these two points throughout the file?
RandomAccessFile database = new RandomAccessFile(databasePath, "r");
int start = 0;
int end = 0;
database.setLength(start);
database.seek(end);
The first start would be the start of the file, the next start would be the end of the first start and so on..
I'm just not sure how to put that into a loop.
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Feb 13, 2014
So i am creating a File object which has a text file passed to it. I then try to do logic with it using a BufferedReader. However, I get a FileNotFoundException on the using my code below. The Error is on the BufferedReader line. I
Java Code: System.out.println("--Reading text file--");
File file = getFile(c,fileName) // Returns a File object.
System.out.println(file); // Shows me the file is looking correct. Displays contents to console.
BufferedReader br = new BufferedReader(new FileReader(file));
System.out.println("BUFFERED");
while((line = br.readLine()) != null) {
try {
// Do Logic
}
catch(Exception ex){
ex.printStackTrace();
}
br.close(); mh_sh_highlight_all('java');
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Aug 25, 2014
I have a problem with € symbol ... an application write a String content on the file system with following code:
out = new FileOutputStream(strPath + "import.xml");
out.write(trp.getTrpXMLModel().getBytes("ISO-8859-1"));
It's correctly wrote on the file system:
TT;Pierre-H€enri;;Orange Grove;zefezfezfez, Directeur Juridique;TT;;azdaz;01 53 33 56 87;ezfezfez;01 53 33 51 59;.....&ée&ée;;;;;;132;CORDIAL;aaa
But when the application try to read the previous file with following code:
BufferedReader in = new BufferedReader(new InputStreamReader(inStream,"ISO-8859-1"));
String line = in.readLine();
The application isn't able to properly read the symbol ... and return following line, without "€":
TT;Pierre-Henri;;Orange Grove;zefezfezfez, Directeur Juridique;TT;;azdaz;01 53 33 56 87;ezfezfez;01 53 33 51 59;.....&ée&ée;;;;;;132;CORDIAL;aaa
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May 13, 2012
I am looking for a pure java api that can read metadata from an mp4 file, I have looked online but all apis I found are wrappers to native code. How to read mp4 with java .....
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Oct 11, 2014
I'm having a bit of trouble with using the Scanner and the Printwriter. I start with a file like this (1 = amount of Houses in the file)
1
FOR SALE:
Emmalaan 23
3051JC Rotterdam
7 rooms
buyprice 300000
energylevel C
The user gets (let's say for simplicity) 3 options:
1. Add a House to the file,
2. Get all Houses which fullfil requirements (price, FOR SALE / SOLD etc.) and
3. Close the application.
This is how I start:
Scanner sc = new Scanner (System.in);
while (!endLoop) {
System.out.println("Make a choice);
System.out.println("1) Add House");
System.out.println("2) Show Houses");
System.out.println("3) Exit");
int choice = sc.nextInt();
Then I have a switch for all of the three cases. I keep the scanner open, so Java can get the user input (house = for sale or sold, price = ... etc). If the user chose option 1, and all information needed is inputted and scanned, the House will be written to the file (which looks like what I typed above).
For this, I use try (PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("Makelaar.txt", false)))). This works perfectly (at least so it seems.)
If the user chose option 1, and all requirements are inputted and scanned, the Houses will be read (scanner) from the file and outputted. For this I use the same Scanner sc. This also works perfectly (so it seems atleast).
My problem is as follows: If a House has been added, I can only read the House(s) which were already in the file. Let's say I have added 2 houses, and there were from the start 3 houses. If option 2 is chosen, the first 3 houses will be scanned perfectly. An exception will be caught for the remaining 2 (just added) Houses. How can I solve this? I tried to close the Scanner, and reopening it, but apparently Java doesn't agree with this
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Jan 24, 2014
I have a unix program that simulates an accident evolving as a function of time and produces two files. I will focus on the first file before getting to the second. This first file has five output variables/vectors (velocity vs time, pressure vs time, etc), which are selected as part of the simulation input. These are the variables I have to put into Excel if I want to view the transient graphically. Where it gets tedious is that, if I want to view a different set of five variables, I have to rerun, extract, put these in Excel to plot. There can be lots of variables needed to properly characterize the accident.
The second file produced is a really large binary file. This file contains all the information that I'd need, precluding the need to rerun to view a different set of output variables. This is the file that seems tailor-made for a Java or something to be able to extract the information. That is, it seems like Java could be used to do this work: extract variable information from the large binary file. Eventually, I would like to plot it too and I know I could use Java there.
I think my steps are:
1) understand the format of my binary file
2) reconfigure the binary file for use with java (is this demuxing?)
3) learn java programming for this application: extracting information to produce something like a .csv file with time on the leftmost column and variable information populating the rest of the columns.
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Jun 25, 2014
I'm getting an IllegalArgumentException returned when I try to get a file using guava library.
I previously had the function working when the file was in a different location, before I switched to running JBehave, my steps run but it fails to find the resource, even after I've moved it.
The code being executed is (this worked previously before using JBehave):
String xMLTemplateFileName = "OBOE-confirmation"
public static void setXMLTemplateFile(String xMLTemplateFileName) throws IOException {
URL url = Resources.getResource(xMLTemplateFileName+".xml");
The file I'm looking for is in the root folder for src/main/resources and also src/test/resources, previously I had it within a completely different location before I switched over to JBehave. I've tried it within a subdirectory in the same locations too.
I've recently updated the pom.xml to try to include the location required.
Extract from pom is below:
<!-- JBehave Build Details -->
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>jaxb2-maven-plugin</artifactId>
<version>1.6</version>
[Code] ....
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May 10, 2014
i m working on the SMS receiving using AT Commands using JAVA. i m getting the message of one page correctly using AT commands, but as i increase the size of SMS as 2, 3 or bigger pages the alphabets are converted to some thing like this
+CMGL: 0,"REC UNREAD","+923028910082",,"14/05/10,19:32:40+20"
4469616C202A3334352A393333232061757220536972662052732E3230206D65696E2
0332064696E206B6120696E7465726E65742028333030204D422920686173696C206B
6172656E21207777772E776170747269636B2E636F6D2070657220736F6E6773206175
722067616D657320656E6A6F79206B6172656E212042616C616E636520636865636B2
06B206C7965202A39393923206D69
Whats the problem i m not getting the right text which i have sent through my mobile phone.
My function of receiving SMS is as follows :
public void send(String cmd) {
try {
outputStream.write(cmd.getBytes());
} catch (IOException e) {
e.printStackTrace();
[Code] .....
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Jun 6, 2014
I am creating an application with having a callerID module. This module is to read calling phone number from modem. I have googled and reference many SerialPort related stuff but could not find a concrete solution. I am able to detect phone ring using serialEvent with javax.comm jar.
I am wondering if AT commands can be used to read/get calling phone number. I also referred following AT commands:
AT+CLIP
AT+VCID
AT+CNUM
1. Is it possible to read calling phone number using AT commands or any other alternative
2. Which AT command can be used and how to send from java application..
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Oct 14, 2014
I am developing a program that reads a digital certificate in a USB token, but can not cause the program to access the token.
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Apr 25, 2014
We're learning how to use Binary I/O commands...which equates to....
My issue is trying to relate the Fraction objects (which we are to create using a loop) with the read/write methods used in Binary I/O (input/output streams). I left a blank after the output.write(), so you can see where the issue exist.
Java Code:
import java.io.*;
public class FractionTest {
public static void main(String[] args) {
int [] fraction = new int[3];
for(int i = 0; i <= fraction.length; i++){
Fraction numbers = new Fraction();
[Code] ....
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Apr 22, 2014
I am creating a web application that runs on server X(unix) and it has another unix system mounted on it. I want to generate the file tree structure of this mounted unix file system and show it on to a web application so that users can select a file and move it onto this current unix machine.
I know this sounds stupid and you may want to say why cant we directly copy the file, I am doing a proof of concept and using this as a basis.
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May 7, 2014
I cannot get the data file to print out correctly when I go to the display case. It only prints one name three times.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.lang.*;
import java.util.Scanner;
import java.io.*;
import java.text.*;
import java.math.*;
import java.util.StringTokenizer;
[Code] ....
Output when I choose Case 1:
Minia
Minia Jane
Minia Jane
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Jun 25, 2014
Let's say I have a text file and in the text file exists file directories as such:
'assets/picture1.png'
'assets/picture2.png'
And so on...
How would I then read from this text file and then create those files using 'new File()'?
Here is my code:
private void getFiles() throws IOException{
files = new File[10];
Scanner scan = new Scanner(new File("files.dat"));
int count = -1;
[Code]....
It does print out those files, but it doesn't create them.
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Sep 22, 2014
I know that it's possible to retrieve a line from a txt file but say for example my file looked like this:
staff id = 1
firstname
surname
age
staff id =2
firstname Kate
surname Hollar
age 33
staff id =3
firstname Daniel
surname Hong
age 21
It is possible to retrieve just the staff id's?
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Aug 12, 2014
I have a code that clear old text then add new text to text file afterthat download the file but the problem my code dose not add new text
FileInputStream fileToDownload ;
private static final int BYTES_DOWNLOAD = 1024;
response.setContentType("text/plain");
String name = request.getParameter("n");
String text = new String(request.getParameter("text").getBytes("iso-8859-1"), "UTF-8");
[Code] ....
How to clear old text then add new text to text file
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May 20, 2014
I would like to create a component to detect the file being modify before process.is it the right way to detect the file modification based on file size value?
Below are the flow:
1. Get the file size of a file
2. Used file size value encrypt it with MD5 algorithm, and say it generated us encrypted value "0123sdf"
3. to avoid user modify the file content, before file process, we take the file and do the encryption with md5 again, if it return value "0123sdf", then we are sure it doesn't have modification.
my question:
a. is it the right approach to detect file modification?
b. what the library advise to use or using java.security.DigestInputStream will do?
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Jul 30, 2006
I want to create hidden files, some sample code for doing this.
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Nov 14, 2014
I upload a file and save it like the following
byte[] uploadedFileBuf = new byte[(int) uploadedFile.length()];
saveFileSystem(excelUpload + getLocalFileName(acad_year, stuid), uploadedFileBuf);
private boolean saveFileSystem(String filename, byte[] data){
try{
FileOutputStream fos = new FileOutputStream(filename);
fos.write(data);
fos.close();
[Code]...
I can not read it use
HSSFWorkbook WorkBook = new HSSFWorkbook(new FileInputStream(filename));
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Jul 17, 2014
I have a log file which goes like this..
INFO: Jul 07 00:00:15 DataSource 2zvw8p93107gev14wko86|34e51ca2: Total connections 4 idle 4 busy 0 unclosed orphans 0 pool unknown
PERFORMANCE: Jul 07 00:00:15 Garbage Collection: ParNew 5 51ms in 59 seconds. [SpeedoLoggingBean] Thread SpeedoBean
INFO: Jul 07 00:00:15 Speedo: 2,222,786K of 4,054,528K - 1,831,741K free, 4,952epm, 1 buffered, 216 threads, 49.1% CPU, permgen 173,731K of 262,144K - 88,412K free
Jul 7, 2014 12:00:15 AM org.geotools.data.wfs.v1_0_0.WFSTransactionState commit
SEVERE: number of fids inserted do not match number of fids returned by Transaction Response. Got:1 expected: 0
[code].....
What I need is to grab only the last hour data from this log file?
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Aug 28, 2014
I have been going over my code line by line, over and over again for nearly and hour now...When I execute method `file.createNewFile()`, the method returns true and throws no exceptions. It even says that the file exists. However, the file is not created and cannot be accessed until the program has exited.
File portLib = new File("");
private class RememberPortAction extends AbstractMenuItemAction
{
methods...
protected void actionPerformed() {
LibraryCreator creator = new LibraryCreator(self, logger);
File newPortLib;
[code]....
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May 25, 2014
My program creates a file but cannot write to it and i cannot figure out why.
How can i fix this code so that the FileOutputStream writes the String "Output" to the file HighScore.
public boolean ScoreWriter(int HighScore, int ScoreNum){
boolean writ = true;
System.out.println(HighScore + " " + ScoreNum);
try{
File ScoreFile = new File("HighScore");
if (!ScoreFile.exists()){
ScoreFile.createNewFile();
}else if (ScoreFile.exists()){
ScoreFile.delete();
ScoreFile.createNewFile();
[code].....
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Jul 24, 2014
I do most of my file I/O with {Scanner} for input and {PrintWriter} for output. I've got lots of places in my code that looks like:
Scanner source = new Scanner( new File( sourceName));
PrintWriter dstntn = new PrintWriter( new BufferedWriter( new FileWriter( dstntnName)));
But when I call the constructor for {PrintWriter} up above, it overwrites whatever the original contents of the file designated by {dstntnName} were, doesn't it? Is there a way to call the constructor so that any future writes to it simply append to the original contents, instead of overwriting them?
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Oct 23, 2014
When my app starts up is it possible to create a blank xml file in the c drive? so I can use it later on down the line
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Feb 7, 2006
I have to divide a text file into blocks of 128 bits. I think i must use the ByteArrayInputStream and ByteArrayOutputStream classes. is there any website showing how to user these two ByteArrayInputStream and ByteArrayOutputStream classes in detail. or it would be much better if you could show me a portion of the code.
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Jul 16, 2014
When I am trying to read data from BufferedReader and writing into excel using FileOutputStream object with POI APIs then i am getting the data in excel file in bad formats. you can check the log file and excel file attached for more information.
Here my problem is I cannot use BufferedWriter in place of FileOutputStream because POI class XSSFWorkbook only have one write method and we can only pass FileOutputStream class object there.
public void readFile()throws IOException {
BufferedReader inputStream = null;
FileInputStream fis=null;
InputStreamReader isr = null;
//Blank workbook
XSSFWorkbook workbook = new XSSFWorkbook();
[Code] .....
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