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Java I/O Q&A » Operation » check 1 




1. check file exists java    stackoverflow.com

i want create text file but if the file already exists it should not create new file but should append the text to the content (at the end) of the existing ...

2. Java: Check if file is already open    stackoverflow.com

I need to write a custom batch File renamer. I've got the bulk of it done except I can't figure out how to check if a file is already open. I'm ...

3. How to check whether the file is using/reading or not in JAVA?    stackoverflow.com

I am using Java to develop an application, it needs to manage the file on the computer. The application have the ability/function to delete the file on the system. But I ...

4. How to check for a dynamically created file in Java?    stackoverflow.com

I have an application where I need to check for a file which may be created dynamically during my execution, I will give up after some MAX time where the file ...

5. How to efficiently check for a proper sequence of files?    stackoverflow.com

I need to check a directory for the presence of a sequence of files. For example at the root directory, the requirement is that if there's a file named: love.dat, then there ...

6. how to check if a Java program is keeping open a handle to a file?    stackoverflow.com

I have a Java program running under Windows XP. It reads a file and closes the file, or at least that's what it's supposed to do. Sometimes the file remains locked ...

7. How to check if a file can be deleted?    stackoverflow.com

How can I check that I can delete a file in Java? For example, if a file test.txt is opened in another program I can't delete it. And I have to know ...

8. Checking if a number entered is odd    stackoverflow.com

`I'm not sure what code to insert or even where, but I would like to check the number I enter is an odd number.

    import java.io.*;

import javax.swing.JOptionPane;

public class ...

9. Check if a file exists, and if so create a new file with a higher number    stackoverflow.com

I'm trying to output a set of points that my program creates, and I would like to be able to run it multiple times without having to manually move the files ...





10. Magic number file checking    stackoverflow.com

I'm attempting to read magic numbers/bytes to check the format of a file. Will reading a file byte by byte work in the same way on a Linux machine? Edit: The following ...

11. Checking file size always    stackoverflow.com

Possible Duplicate:
Size of folder or file
How to do such a loop that will check the file size, and if it change then output something ...

12. Reading characters and checking if they're a number    stackoverflow.com

I am trying to get a method that checks if character after the symbol & is a number or a letter; if a number, it is translated into binary; and if ...

13. Check statically a file existence    stackoverflow.com

I'm wondering if exist some way to check if a file exist without create an instance of java.io.File Always I have used the following way:

File f = new File("./path/to/file");
if (f.exists()) {
  ...

14. How to check if a file is being read    stackoverflow.com

Could someone tell me whether it is possible to check if a file is being read. If it is being read then how do I make my program wait, till the ...

15. Java, how to check the existence of file    stackoverflow.com

I have this small code

    File source;
    if ( !source.exists() ) {
        source = new File("instances/student"+student.getStudentID()+".data");
  ...

16. Is there a proper way to check for file/directory existence in Java?    stackoverflow.com

Code:

String dir = //Path to the  directory
File saveDir = new File(dir);
//Here comes the existence check
if(!saveDir.exists())
  saveDir.mkdirs();
This part of code is used to save files with a given directory ...





17. Check file exists by its part name    stackoverflow.com

How to check file exists by its part name gracefully in Java? File should be created once a Day with name as Timestamp and further should be appended. Writing to file performed multiple ...

18. to check the modem    coderanch.com

hai , i want to check whether the modem is working or not. i use java with linux. i send a string "AT" to /dev/modem (i am write to the file /dev/modem and wait and then read out from the file /dev/modem) it responds with OK. after that i send "ATDT," this works fine for sometimes but othertime , i am ...

19. How to check for the changed file    coderanch.com

Hello Everyone I have a file/folder which needs to be monitored for period of time. How can i check to see if the new files have been added or deleted or changed in the directory? can i use XML with java to take a snap shot of the file and compare when it changes? if so how do you do it? ...

20. How to check EOF in Java??    coderanch.com

This depends on the InputStream or Reader object you are using and the method you are using from that object. If you are using the readLine method of BufferedReader, it returns null on the next read after the last data is read off the stream. If you are using the read(byte[], int, int) of FileInputStream, it returns -1 when there is ...

21. file checking in the remote machine    coderanch.com

22. Checking for a file name with a date/timestamp mask    coderanch.com

I have files posted to a directory on a daily/weekly basis that have a date and/or timestamp as part of the filename. For example, myfile02142002.txt. The file name will always have the same "stem" (i.e., myfile in this case) but the date/timestamp will be different. In my database, I have 2 fields that are used to build the file name format ...

23. How to check if I'm reading the same file    coderanch.com

Say I open a file, do some stuff w/ it, and exit the application and the file is closed. After couple of days, I want to read the same file(same path) but not sure if that file is newly created or is the same old file, can anyone tell me how do I check that in JAVA? thanks

24. Checking for EOF    coderanch.com

25. Checking if file is in use    coderanch.com

If you are using a JDK version prior to 1.4, what is the best way to check if a file is being used by another application? For instance, a VB application creates and writes to FILEA in a directory. At the same time, a Java program tries to open and read FILEA from the same directory. What is the best way ...

26. checking file extension    coderanch.com

Hi guys, how can I check if the extension of a file is valid? What I mean is, someone could just change the extension of a file to an invalid one. Or the file might be corrupted. And if it's not valid, how can I know the real extension? I need to do this with Java code.

27. how to check if a string exists in a file    coderanch.com

Hi AJ, Well, there's more than one way you could do this, but general, you need to: 1) Read in the file, line by line 2) Check each line for the pattern 3) If you find the pattern, print the "found" message 4) At the end, if you never found it, print the "not found" message. You can do 1) using ...

28. how to I check when a file was last modified ????    coderanch.com

Hello, I cant seem to get this to work: this is a JSP page: ----------------------------------------------- <%@ page import="java.io.*" %> <% //this is the folder I am trying to get info on //i want to find out when it was last modified File dir = new File("/usr/local/test"); String lastmod = dir.getLastModified(); %> ------------------------------------ I get this error: cannot resolve symbol symbol : ...

29. Reality Check    coderanch.com

Returning to a question that I posted a while ago (see http://www.coderanch.com/t/276466/Streams/java/IO-Tiger is there any "scanf"-like feature in Java beta SKD 1.5? In particular, is there a way to input say, an int value, with just one or two lines of code? [Is there a scanf("%d", n) or maybe a getInt() that takes keyboard input?] I wouldn't ask this question a ...

30. How to check file is in use.    coderanch.com

That will be a hard work - if not impossible at all. Can you define, what you mean with 'in use'? When I open a small file in an editor, the editor may close the file after reading. When I save it to disk, the file can be reopened again - or a new file is written with the old name, ...

31. Duplicate file (contain of the file, not the name!) checking    coderanch.com

I'd probably use a stream of some sort to read byte arrays and compare one byte at a time. Check that the file length is equal first. If you want to ignore the difference between Unix & Windows newlines you could use a reader instead of a stream and read lines, or just skip all \n and \r when comparing bytes. ...

32. Duplicate File Checking.    coderanch.com

Hi All, I am describing the scenario where I have to check the file duplicity. I upload a file in client site(internet-explorer) and sent to server and again when I upload any file that contain the same date, then at server side some validation should be imposed such that the latter uploaded file can not be processed further. One solution that ...

33. check file whether it contains valid data    coderanch.com

Hello, I'm using Apache-FileUpload to get all the datas. One of the data is my image file. I have an image file of size 6 bytes but it is corrupted one..On reading(InputStream.read()) I can get the bytes. But on opening the file manually it's showing "PNG Decode" error. Are there any code to check whether the file contains proper image or ...

34. Check whether Direcotry Exist..    coderanch.com

35. Checking if file is open in Java    coderanch.com

Hi there ! I am doing the exception handling in a java program. I don't want to copy, transfer or delete a file if it is open. The trouble is: I can't find in the java API's any method that would check if a file is open. Can anyone help ? Cardoso

37. how to check a file is writing or finished    coderanch.com

I don't think there's any easy way, if there isn't some specific feature in the file format you can discern. What I usually do is write files to a temp directory and after that succeeds, the writing app renames the file to the proper target directory. That way, if another app can see it, it's all there. This is a good ...

38. File length check - Help    coderanch.com

I have to do check the file length from the passed InputStream. And after that, it has to be passed to another class. But after checking length of inputstream, getting file length as 0. anything wrong in this method to check the file length: checkFileLength(InputStream inpStr){ BufferedInputStream bufInput = new BufferedInputStream(inpStr); int data, len = 0; try { do { data ...

39. Checking Printable Characters    coderanch.com

Hi there, I am a student and a Java newbie. What I am trying to do is write a program that does a hex dump of an input file and also print out the contents of the file in regular ASCII text. It mostly works except the output file contains some garbage characters so I figure I have to check each ...

40. how to check non english string    coderanch.com

I don't think there's a perfect answer to this question, because many languages besides English are written using the same alphabet as English. I'm no expert on this topic, but I think the first thing I would try would be checking for Java char values greater than 127 (the upper limit of the ASCII set). For strings written entirely in non-Roman ...

41. Checking a file has been split properly    coderanch.com

Hi, I am writing a program which will split a file into multiple smaller files. Following this I then need to make sure that all of the data is in the split files. Following the splitting operation I was thinking about counting the number of lines in the master file and then counting the number of lines in each of the ...

42. check if a file exits    coderanch.com

43. Checking File Type    coderanch.com

Hi, I am uploading a file, how can I ensure that the file being uploaded is only in text format. i.e if the user changes the file extension of exe to txt, still then , my program should point out that this file is not a txt it is an exe. any one have any idea. My requiremtn is to allow ...

44. how to take and check input in Java    coderanch.com

45. Checking for File Open or Closed state    coderanch.com

Hello, I am working on project that requires checking to see if a file is open or closed. The application takes the information in the file on one system and places it on another system to modify. I have tried setting up a file lock so that I can lock the file using the FileChannel and FileLock api's. I am in ...

46. Checking Package Hierarchy    coderanch.com

How to check package hierarchy? Suppose I have to display all classes contains in a Package P1, and P1 contains 2 sub Package P2 and P3. P2 and P3 have also few classes. So how we can check the folder hierarchy? I have used this - if (directory.exists()) { // Get the list of the files contained in the package String[] ...

47. Checking empty file    coderanch.com

Hi Friends, 1. I want to upload various file formats like TXT,CSV, .XLS in our web application from browser. But before that I want check whether file is empty or not. Can anyone suggest best practice to check file is empty or not. 2. When I use length() function for File object it provides required result. But when I use "%" ...

49. check File Existence and display alert message    coderanch.com

Hi, I have a servlet which uploads file to server. Below is my code and is working file. Now, I want to check if the file uploading by the user is already exists. If so , I have to display a message to user "The file you are trying to upload already exists. Do you want to overwrite" with YES or ...

50. Checking for a Modified File    coderanch.com

I have an homework organizing application in which you can save you assignments to a file. I want to be able to, when the users exits, and if the document is modified, prompt to save changes or not. How would I go about calling a function to do this on a person choosing to close (I would know how if they ...

51. checking to see if a file write is successful    coderanch.com

Hi, I am writing a program that takes in a file, sorts it, and then writes it back to another file. What I want to do is, check to see if the file is written successfully, and then display the message "File written successfully" out, because I have no other screen output as of now. Is there a condition to check ...

52. Checking if a file is binary/ascii in Java    coderanch.com

A quick look at the ASCII character set shows it only uses the first 127 byte values. You could read with a stream and see if you find any bytes with value over 127. That would make them negative in Java, wouldn't it. Uh oh, the "extended ascii" set uses all 255 values. With that, you're out of luck. Can you ...

53. check if File is hidden or system file    coderanch.com

Hi, Let me explain my concern: I'm filling a JTree with user system files/folders and I'm using the File class for this purpose. I noticed the JTree displays also hidden & system files which will confuse the user of my application. I first thought to use some File method & isHidden() was first candidate.I first tried return file.isHidden() but that's not ...

54. Check whether a file is being read while trying to overwrite it.    coderanch.com

Hi, In JAVA, is there anyway I can check whether a file is being read while trying to overwrite it. I have a JAVA program that overwrites a huge file every 5 minutes, but it seems to give problems to our clients when reading the file exactly the same time when it is being overwritten. Thanks in advance for all the ...

55. Check if file Exists    coderanch.com

My class makes a remote connection to an iseries machine. I need to check the existance of a file. I use SQL Select to do that. If the file exists I stop my code and tell the user to wait until this file has been processed by accounting. The code needs to proceed if the file does not exist. My code ...

56. checking for existence of file    coderanch.com

hi friends, if i wanted to check if to see if a file exists in certain directory do i just use the .exists()? for example on a good day there should be only one file in C:\stuff\ called download1.txt, on bad days there are 2 files a download1.txt and download2.txt , so i guess i should just check initially are there ...

57. How to check if a file contains a given string?    coderanch.com

import java.io.*; public class Grep { public static void main(String[] args) throws IOException { Reader in = new FileReader(args[0]); char[] data = args[1].getChars(); // <--- // there should be a method something like this in there. // I don't have specs with me int place = 0; char c; while ((c = in.read()) != -1) { if (c == data[place]) { ...

58. how to check if file is empty    coderanch.com

59. checking for file existence    coderanch.com

Dear All, Thankyou for your most useful responses to date. I have another question: I would like to know how to determine whether a file EXISTS in a specified folderpath. I have attempted to do it by writing this function:- private boolean check_file(String path, String fname) { boolean status = false; File dir = new File(path); File fil = new File(dir, ...

60. Check for invalid file name    coderanch.com

something like this might be all you need to do import java.io.*; class Testing { public Testing() { boolean validFileName = false; do { System.out.print("Please enter filename: "); try { BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in)); File filename = new File(stdin.readLine()); if (filename.exists()) { System.out.println("\n** RECTANGLE SAVED **"); validFileName = true; } else System.out.println("file does not exist, try again\n"); } catch(Exception ...

61. check whether files are in use    coderanch.com

I have a folder which consists of few folders which in turn consists of .tiff images files. I want to show the folder to the user only when these tiff files are not being used by some other processes. How do I check that? how to check whether the files are being used by some other process? Thanks.

62. how to check the channel count    coderanch.com

63. How to check the file size?    coderanch.com

64. Program to check whehter a file is read-only / write    coderanch.com

import java.io.*; public class FileTest { public static void main(String[] args) { File f = new File("file-name"); if(f.canRead() == true) System.out.println("Read Only"); if(f.canWrite() == true) System.out.println("\nWrite Only"); } } Using this program you can able to check whether file is read-only or write-only. File class has many properties for that you can check it.

65. utf-8 character file -check    coderanch.com

66. How to check if file contents read matches what was written    coderanch.com

A friendly place for programming greenhorns! Register / Login Java Forums Java Java in General How to check if file contents read matches what was written Post by: John Vorwald, Ranch Hand on Sep 27, 2010 20:37:22 I would like to check if the data read from a file is the same as what was written. Does the following ...

67. Not able to check-in the files to CVS using JCVS api    coderanch.com

Hi, I am creating the component for check-in the files to CVS using JCVS api for one of my project. I was not able to check-in the files to CVS using the newly created component . Would be appreciated if anyone post the working code for the check-in and check-out operations using JCVS api. Here is the code which i have ...

68. check PGP in downloaded files    coderanch.com

69. Check File Exist using javascript    dbforums.com

Hello. I am new in this forum and i face some problem in my school project. i would like to know the javascript without using Active X on how to check file exist in a local drive. Because using active X , i unable to run my script on Mozilla firefox. Thank you

70. checking file extensions    java-forums.org

Hi, The code i have made i believe should check for a certain file extension and then send it out the socket. Java Code: public void run() { Server sv = new Server(); File folder = new File(sv.getFilePath()); File[] listOfFiles = folder.listFiles(); out.println(listOfFiles.length); for (int i = 0; i < listOfFiles.length; i++) { if (listOfFiles[i].isFile()) { //make sure its a file ...

71. How to check file existence and rename file with little modification    java-forums.org

Hi, Hope you all will be fine. I want to ask i created a file named msg0000.wav in a directory named 220. Now i want to check if msg0000.wav already exist in the director then make a new file but with name msg0001.wav in the same directory and after reaching to number 9(msg0009.wav) it becomes msg0010.wav, msg0011.wav and so on. Means ...

72. Checking for a file till a particular time    forums.oracle.com

73. Checking whether a file is empty or not    forums.oracle.com

You could do the following. You open the file, append x bytes to the end of the file. Then you close it, open it again count the total number of bytes you can read from the file, substract the number of bytes you wrote to the file and if the result is zero the file originally was empty. Or you just ...

74. Help me on this checking modified files.    forums.oracle.com

Hi, This is regarding about handling files in java. My application is accessing by different user and they are changing the configuration files in the deployment folder. I have to check the modified files in the particular folder and that changed files data should be write it into new log file. So that I can find it in the log file ...

75. Checking if a file is finished writing (lockable?)    forums.oracle.com

Hi all - I need help to find a method/class/code that can check if a file (.txt or .doc or .dat, etc) is still being written by an outside application before I move it to another location. A simple example situation is: 1) An application is writing a large file to a shared drive. 2) My java code needs to move ...

76. Checking for a valid file name    forums.oracle.com

and you should define the concept of a "valid filename" as well. Depending on your operating system and what you want your application to be capable of a lot of things may or may not be valid. If a directory does not exist, it can still be valid if it can be created for example, but you may decide that you ...

77. To check that a JPG-file is a valid JPG-file ???    forums.oracle.com

My requirement is such that Uploading permits only the graphic files (such as .jpg,.gif,.bmp,etc's). So during uplaoding i need to check whether the file.endsWith() jpg or etc's to go further where this is the normal way. Then i read the Bytes of the graphic file through DataInputStream.readByte() to find whether it is a valid graphic file . he problem is that ...

78. Checking if filenames are present inside a set of files    forums.oracle.com

NullPointerException is different from simply getting null as output. In your catch block add ioe.printStackTrace(); Then, find the line number referenced in this stack trace and post that line here again. Edit: And of course both files are getting emptied out. After the exception the temp file is closed without it having been written (or at least not completely) and yet ...

79. How will i check the extension of the file.    forums.oracle.com

81. Check file exists    forums.oracle.com

82. How to check if a file exists?    forums.oracle.com

I have a program that writes to a text file whose title is given by the user. I need to change the program so that it checks to see if the file name already exists before it changes anything. How would I go about doing this? Edited by: Freddy7777 on Jul 24, 2009 2:52 PM

83. check a file exists on a remote machine    forums.oracle.com

The only way to do this if the remote machine somehow supports remote file access via a protocol such as FTP, SMB, NFS, ... And even then, you usually can't check for some physical location on the filesystem but only see the logical view that those filesystems present (which may or may not differ from the organisation on the physical storage). ...

84. checking file write completion    forums.oracle.com

Well, there are sort of two issues: 1) Knowing when the file has been completely written. 2) Informing the second thread that something has happened. Given that he wants to have one thread write the file completely and then have the other thread read it, it doesn't really sound like something that should be multithreaded in the first place. However, ignoring ...

85. File extension check    forums.oracle.com

86. Check filename structure    forums.oracle.com

87. How to check data file was created?    forums.oracle.com

88. Anyway to check end of a music file?    forums.oracle.com

I've got some code to play a music file. i wanna create a loop. Is there anyway to check if the music file has reached end of file. The code is actually using an AudioStream object to play the file. Is there anyway to check if the stream has ended so the loop can start its next iteration. Here is the ...

89. how to check whether a file is empty or not    forums.oracle.com

if i create a file File f = new File("path"); f.createNewFile(); Now i have created this file.. but i havent wrote any thing to it.. how can i determine that whether this file is empty or not.. Secondly, once i write some thing to file.. how can erase all the data from file ?

90. Check if file is opened    forums.oracle.com

But if the locking mechanisms are used then only the java vm takes it into consideration for all the running java processes, isn't it? As far as I read these mechanisms are not handed over and read from the underlying operating system. So if other system processes involved into the workflow then the java locking mechanisms cannot be used. - However ...

91. Tool for checking file handles    forums.oracle.com

Not directly related to Java, but does anyone know a good tool for checking which files are opened by an application? Not closing an InputStream is a very common mistake unfortunately, so it would be great if I would be able to see which files handles are being held by an application.

92. Check if a file is open or not    forums.oracle.com

I am trying to check if a file is open or not using Java. I did get a partial solution. It is: Take the filename. Rename the file to a different name If the new filename exists, then it is not being used by another program( which in turn means that the file is not open). If the file is accessed ...

93. How to Check whether the file object is a System file in Java ???    forums.oracle.com

Hi All, I need to write a logic to retrieve all the files other than System files from the given folder. Currently when i give C:\ it moved all the files including System files. Can anyone please tell me is there is any way in Java to check whether the current file object is a System file or not? Thanks, Kathir ...

94. How to check existing time for a file    forums.oracle.com

Hi Friends, I have a JSP program which will generate some image files to display on the web. I would like to check those files for their existing time. Like as if file existing longer that 5 minutes I will delete it. Does anybody know how to do it in Java? Thanks.

95. Checking status of a file    forums.oracle.com

Hi guys, Need help for this problem. Is there a way in java to know the status of the file? Here is the scenario of my problem. My program doesnt need to allow the user to open a file if the file is still on writing process. Thanks... just let me know if you don't understand my question. Thanks in advance. ...

96. how to check if a file is open    forums.oracle.com

97. Checking for File Open or Closed state    forums.oracle.com

Hello, I am working on project that requires checking to see if a file is open or closed. The application takes the information in the file on one system and places it on another system to modify. I have tried setting up a file lock so that I can lock the file using the FileChannel and FileLock api's. I am in ...

98. How to check file integrity    forums.oracle.com

Why do you think you need to "check file integrity"? What does "checking file integrity" mean to you? The file system, disk controller, etc. are responsible for making sure that the bytes that you try to write get written correctly. Assume that they work. If you have reason to believe otherwise, you need a diagnostic tool, maybe a new disk, not ...

99. Check if file is being accessed    forums.oracle.com

Warnerja: Just because something like Notepad is displaying what it saw in the file doesn't mean the file is being accessed by anything. You have a weird 'requirement'. If you "print" the contents of the file and hand out copies to people to look at, do you need your application to know if anyone is currently looking at the paper too? ...

100. How can I check if a file exists?    forums.oracle.com

hmnn maybe someone more knowledgeable will chime in, but I'm not sure that you can do that directly using the .exists() method. My assumption would be that you would have to get a directory listing of where you want to create this file and compare the new file name against the filenames returned in the directory listing...

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