1. random access file in java stackoverflow.comI have the following fields:
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2. Java RandomAccessFile stackoverflow.com |
3. Clean a RandomAccessFile stackoverflow.comI have a code: |
4. Java RandomAccessFile - dealing with different newline styles? stackoverflow.comI'm trying to seek through a RandomAccessFile, and as part of an algorithm I have to read a line, and then seek backwards from the end of the line E.g |
5. deleting random access file in java stackoverflow.comI've created a random access file as follows: |
6. Delete The First Bytes of a Random Access File in Java stackoverflow.comI'm writing bytes to a random access file. After completing the operation, I want to delete the first 100 bytes from the file. How can I achieve this? Thanks in advance. ... |
7. RandomAccessFile readInt stackoverflow.comhow to read numbers from a file??? when i use readInt method i get big number, and it not equals number from a file. how to fix it??? Scanner is not good idea, becouse ... |
8. java.io.RandomAccessFile Invalid Argument for large files on mac stackoverflow.comI'm running a program which needs random access to a very large file (approximately 151 gigabytes). I've found that whenever it runs on one of the MacPro machines in the ... |
9. Is it possible to set a speicifc byte in a RandomAccessFile back to null? stackoverflow.comOrigianlly, when I created the RandomAccessFile, I skipped over some bytes so those stayed as null, but now I need to delete some of the bytes I wrote. Right now, what ... |
10. Closing a RandomAccessFile sometimes takes exactly 45 seconds stackoverflow.comIn my program, closing a java.util.RandomAccessFile sometimes takes exactly 45 seconds (well, almost exactly: between 44.998 and 45.003 seconds). The program creates and closes lots of small files. Usually closing the ... |
11. RandomAccessFile over HTTP stackoverflow.comIt's easy to open a connection to a remote asset using URL.openStream() which returns an InputStream. What about random access? |
12. RandomAccessFile read/write start-finish position problem stackoverflow.comI've searched this a lot but still can't find... So I hope you can help me to understand :) The question is... I have big file A.dat and I want
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13. How do I delete a record from my random access file? stackoverflow.comI was wondering how I could delete a record from my random access file. Here's how I add to my RAF, not sure how to delete it though :X |
14. RandomAccessFile cannot be found by compiler after being declared stackoverflow.comThe code below produces the following error when I try to compile it:
cannot find symbol |
15. Why no readUnsignedInt in RandomAccessFile class? stackoverflow.comI just found there is no |
16. How to save string with code page 1250 into RandomAccessFile in java stackoverflow.comI have text file with string which code page is 1250. I want to save text into RandomAccessFile. When I read bytes from RandomAccessFile I get string with different character. Some ... |
17. Question about RandomAccessFile in Java? stackoverflow.comI am reading some Java text about RandomAccessFile, in the text, the author says:
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18. Are RandomAccessFile writes asynchronous? stackoverflow.comLooking at the constructor of RandomAccessFile for the mode it says 'rws' |
19. input/output stream on random access file, does close propagate? stackoverflow.comI am creating file input streams/file out streams from a random access file via the following API: |
20. How to choose RandomAccessFile dynamically? stackoverflow.comI had written a program using |
21. In java is there a readObject() alternative for RandomAccessFile stackoverflow.comI'm trying to save a couple of Strings but I'm currently using ObjectInputStream, which apparently doesn't save my data in a permanent manner. Here is the code which I commented in ... |
22. Opening and Closing a File in RandomAccessFile stackoverflow.comI have a program which has to create an empty file with a specific name, write output to it and then close it (not delete it). If the program is run ... |
23. how to Lock the File using RandomAccessFile coderanch.comI am using the RandomAccessFile since there are 2 procress . one process will write in a.txt file and 2nd process will read from a.txt simultanously. i found that data get lost so i would like to set the lock on file that is while reading and writing the file.But locking faclilty is in reader and writer class so whether there ... |
24. RandomAccessFile coderanch.comI don't think this is a correct reason. A URL may not necessarily use HTTP. The reason you cannot have random access to a URL is: There is no concept of a "File Pointer" that you can move around in a URL. All you have is a stream of data. You do not have a "chunk" of data. Furthermore, you can ... |
25. RandomAccessFile.seek() coderanch.com |
26. RandomAccessFile(urgent) coderanch.comHi It depends on what exactly you are trying to do! If you simply wants to read contents of a file, you can use RandomAccessFile no need to use any other classes along with this. You can read any data type with this class. It has wide range of read methods. HtH SivaPrasad |
27. RandomAccessFile coderanch.com |
28. Random Access File - Overwrite Contents coderanch.comhi friends, Thanx friends,let me make my requirement very clear, i am running through the file until the exact book code is found, then i want to overwrite the bookName public void modifyBookDetails(String str){ try{ String bookCode="B0000002"; String bookName= "MasteringJSP"; File f=new File("F:\\javapro\\BookMaster2.txt"); RandomAccessFile raf=new RandomAccessFile(f,"rw"); String line=raf.readLine(); while( line != null){ line=raf.readLine(); if (line != null){ String s=line.substring(0,8); if (s.equals(bookCode)){ ... |
29. RandomAccessFile coderanch.comAlthough we can seek N bytes in a RandomAccessFile and read/write at the N+1 bytes, can we also do the same with lines? Can we skip the N lines and read/write directly at the (N+1)th line? I know we can use the readLine() method and keep a count of how many lines we have read, uptill the point count reaches N. ... |
30. why use RandomAccessFile coderanch.com |
31. RandomAccessFile - overwrite or insert? coderanch.comHi, I would be grateful if someone who has done this sort of work could clarify something for me. I want to use RandomAccessFile to insert new data values into an existing file. If I use something like raf.writeShort() can you tell me whether it will overwrite the existing data at the current byte position, or will it insert new data ... |
32. Restart in a RandomAccessFile coderanch.comI've been looking at the posts in the I/O forum and think I've got the basics of an answer, but wanted to walk this thru with someone. I have to take an existing program that has a property file and input file & process the input file run thru some complex logic. As I process the records in the file (fields ... |
33. RandomAccessFile not fast enough?! / Wait for a stream coderanch.comHello, i am developing an application which processes a file multiple times. At first I generate a TIFF Image with Java Image I/O API which works perfectly well. Then I am re-reading the file to modify some pointers and stuff and this is where my problem starts: The RandomAccessFile used for writing the file to the HD is still writing down ... |
34. java io/reading from Disk file using RandomAccessFile class coderanch.comjava io/reading from Disk file using RandomAccessFile class (I/O and Streams forum at JavaRanch) A friendly place for programming greenhorns! Register / Login Java Forums Java I/O and Streams java io/reading from Disk file using RandomAccessFile class Post by: C.R.Muthukumar , Ranch Hand on Dec 03, 2004 03:09:00 import java.awt.*; import javax.swing.*; import java.io.*; import java.util.*; import java.awt.event.*; import ... |
35. Help In RandomAccessFile coderanch.comHello javaranch members. I have a problem with java.io import java.io.*; class TestRandom { public static void main(String[] args) { String s ="1234567"; String s1="HelloWeee"; String re=null; try{ RandomAccessFile f = new RandomAccessFile("file.dat","rw"); System.out.println("File Pointer "+f.getFilePointer()); re=f.readLine(); while(re!=null) { System.out.println("File Pointer "+f.getFilePointer()); if(re.equals(s)) { System.out.println("After read match lin file pointer" +f.getFilePointer()); f.seek((f.getFilePointer()-re.length()-1)); System.out.println("REpositioned file pointer" +f.getFilePointer()); b = s1.trim().getBytes(); f.write(b); System.out.println("AFterwrite ... |
36. RandomAccessFile not erasing contents of old file coderanch.comI am creating a "testfile" using RandomAccessFile like this: RandomAccessFile raf = new RandomAccessFile("testfile", "rw"); raf.writeInt(2); raf.writeChar('f'); raf.seek(0); System.out.println(raf.readInt()); System.out.println(raf.readChar()); raf.close(); When I ran first time, it created the file with 2 and f and printed properly. Next time, I commented line no. 3 (i.e no writeChar('f')) and ran the program again and again it printed 2 and f. I looked ... |
37. Problem with RandomAccessFile coderanch.comBecause an ObjectOutputStream writes a header, too. Take a look at the size of the file that's been written - it's bigger than just the 4 bytes that writeInt() would give you. You really don't want to read this with anything other than an ObjectInputStream. Or in this case, if you're not going to use writeObject() and readObject() at some point, ... |
38. what's the different between random access file and sequential access file? coderanch.comSequential file access allows data to be read from a file or written to a file from beginning to end. It is not possible to read data starting in the middle of the file, nor is it possible to write data to the file starting in the middle using sequential methods. The input and output streams in Java are sequential. A ... |
39. mode for the RandomAccessFile coderanch.com |
40. Does RandomAccessFile need a bufffer class? coderanch.comIn the case of reading from and writing to a text file, it is helpful to use a buffer class, so that the program stores up the data in a buffer before reading and writing, and does not have to open up the file on the hard disk every time a few characters are added to the file. How about the ... |
41. About RandomAccessFile coderanch.comIs there some ThreadLocal variables in RandomAccessFile, because following won't do nothing: final RandomAccessFile raf = new RandomAccessFile(f, "rws"); Thread t = new Thread() { public void run() { try { raf.write("test".getBytes("ascii")); } catch(Throwable t) { t.printStackTrace(); } } }; raf.close(); .. but if i do write in Thread, which creates RandomAccessFile instance, then it works.. I don't get any exceptions, ... |
42. Random Access File Question coderanch.comhi all ,i was wondering that if i use a RandomAccessFile to save data, should i save empty objects (say 100,000 object) and then for every object that i need to insert ,i seek it's position and then modify the value of the empty object. that i have read in a book (Java2 how to program) is there another way to ... |
43. RandomAccessFile and the lost space coderanch.comAh ha, I see what you mean. I suppose you would have to create the file using dummy entries, yes, as Cay suggests. I think whether this is viable would therefore rely on how large the file would be (and hence how long it would take to create) and also how often you would need to do this (i.e. is the ... |
44. RandomAccessFile coderanch.comOk, im very new at this, and i've hit a road block. In a RAF i am holding data such as Name, address, DoB, phone number... etc. I have worked a way of navigating and adding the data into the file. The method of adding is shown below. Now i've come to a point where i want to ammend or change ... |
45. RandomAccessFile problem during modification coderanch.comThere's no operation for replacing different-sized data in a RandomAccessFile, therefore you have to do it yourself. If the data you are replacing is a different length to the new data, you must move the rest of the file contents appropriately. If the file is known to be small, this is pretty easy. If it could be big, you need to ... |
46. RandomAccessFile Help coderanch.comI have a text file with a path of another file on each line. I have a Java code that reads this file searches for the file on the particular line and takes it's contents. But in case of an error, it writes the line number to a temporary file so i can start exactly where i left. My problem is ... |
47. RandomAccessFile coderanch.comHello everyone! I have the following problem I'm trying to solve: I have a .txt file of data that needs to be read to a mySQL database. The way the data is structured, some "fields" are blank and others are filled with data. I figured a Random Access File would be ideal for this situation. I have never used this class ... |
48. RandomAccessFile() coderanch.comOk fellas, come a long way and i have learned a ton. The two files that I am putting together one after another in the new file is working but...the second file contains several lines at the begining that are contained at the end of the first file so i have duplicate records in the middle of the new file!! Im ... |
49. random access file coderanch.comHi, I have a program that writes to and reads from a random access file. That is, it's trying to... The program loops around (it has a menu that runs in a loop until user chooses to quit), and one of the operations is to read from the file what is in there. The file contains records of an ADT I ... |
50. Deleting from a RandomAccessFile coderanch.comHi, I have a program that writes fixed length records to a RandomAccessFile using a hashing algorithm on a key field. This works fine, but I'm unsure how best to implement deletion of records. People have suggested different ways to deal with this, but I'm unsure which one is best, or if there is an even better method. What are the ... |
51. Creating Random Access File coderanch.comIt is a matter of scope and visibility. The variables you declared in your constructor are not visible to other code, and they become eligible for garbage collection when the constructor exits. Move them to member variables to make them visible to other methods. Here's one way to change things: class TestRaf // cap first letter, not all letters { BufferedReader ... |
52. RandomAccessFile: backspacing and inserting coderanch.comYes, unfortunately RAF really isn't good for this sort of thing. If you want to replace one region with another string with a different length, you need to shift all the subsequent bytes in the file to accommodate the new length. There's no simple method call to do that, and it's a fairly ineffecient process - especially if you still plan ... |
53. problem with random access file coderanch.comI have to append some content to each line in a text file. But when i use random access file and write contents to the file.. the content in next are getting over writed. Is it not possible to write in the middle of a file using random access file without getting the contents next to it overwritten> i have a ... |
54. using a RandomAccessFile coderanch.com |
55. Getting filename of open file (RandomAccessFile) coderanch.comHi, I'm sure that this has been covered somewhere, but I've been unable to find it. What I want to be able to do is create a list of RandomAccessFiles (I'm using them for doing binary searches on sorted, fixed record length, text files). But since I will have a list of them, I'm trying to figure out how to get ... |
56. RandomAccessFile : What is rws and rwd mode? coderanch.comAs explained in the text the changes updated to the physical file before the I/O call returns if the file resides on the local device. The difference between the two modes is that "rws" will write both changes to file contents and file metadata while "rwd" will update only on changes to file contents. |
57. Access Denied Error with RandomAccessFile coderanch.com |
58. RandomAccessFile Modify Help coderanch.comHi all. I have used the following code to create the file. It works. import java.io.*; public class RandAccessFile{ public static void main(String[] args) throws IOException{ BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); System.out.print("Enter File name : "); String str = in.readLine(); File file = new File(str); if(!file.exists()) { file.createNewFile(); file.canRead(); file.canWrite(); // System.exit(0); } try{ //Open the file for both reading ... |
59. RandomAccessFile help coderanch.comI am working on a program and am 95% done, but am stuck. My program creates a file and the user can file it with account ID's and balances. The issue I am having is that when a user enters a duplicate account ID it needs to throw an error and I am thinking after the error it should then ask ... |
60. RandomAccessFile and a big file read/write problem coderanch.comI still don't see the code I asked for. Anyway, if you need to write a 67MB file into 4MB chunks, that should require 16 files of 4MB each and one file with the remaining 3MB. I get a feeling that you're forgetting that last file. 17.3MB gives you 4 files of 4MB which merged together gives you the 16MB from ... |
61. RandomAccessFile coderanch.comWell, it would depend if your file was plain ASCII text or Unicode characters, but the basic idea is the same. Open up the file in read or read write mode, seek() some number of bytes (there is no fseek) then read the three bytes or three characters you need. Where are you running into a problem? |
62. How to update randomaccessfile coderanch.comI'm studying Java, I wrote a Address book for practice. Actually I follow a sample and finally finish. It work fine. It has Add new, Move Next, Move Last, Move First, Clear Buttons. I need to add UPDATE Button. I already Add that button. How can I do the coding? I don't know how to play with " seek(position)" Can anybody ... |
63. Question about RandomAccessFile and MappedByteBuffer java-forums.orgAbout RandomAccessFile's pointer. Lets say I have 5 int values in a text file. I want to the 2nd int in my java program. Then I jump 4 bytes forward (x.seek (4))(the pointer start at 0), because a int is equal to 4 byte. If its a long value, I jump 8 byte forward, and so on for the rest of ... |
64. Random Access File creator errors forums.oracle.comMy main question is is it possible to create and use a Random Access File as part of a class, but outside of any of the classes methods? I have written my code that way, but when I compile, I get an error about the syntax. Below is the code and error message: |
65. Problem with RandomAccessFile forums.oracle.comI am assuming dos.txt is a normal text file, containing some lines of text. Have you tried readLine() method of RandomAccessFile ? It returns a String, so you can read each line using a loop and append the read string to the string in which you want to store your file's contents. For checking if "str" is contained in the file, ... |
66. How To Using A Random Access File forums.oracle.com |
67. NoSuchElementException while making random access file forums.oracle.com |
68. HELP!Random access file forums.oracle.com |
69. RandomAccessFile help forums.oracle.comseek(1) will set the file-pointer offset to 1 past the beginning of the file. writeUTF ("test") will output output six bytes. So won't seek(1) go to to 1 past the beginning write 6 bytes and if you then seek(1) and readUTF() you will read 6 bytes "test". If you do it again for seek(2) writeUTF("test") it will write 6 more bytes, ... |
70. RandomAccessFile readWrite forums.oracle.comIn a text file I have: 56 Jones 33 64 59 barry 66 367 34 scott 88 100 etc I want to remove a line based on the user input - barry removes the whole line - 59 barry 66 367 the pointer is set at 0 How do I find the line and then remove it and write back to ... |
71. Using RandomAccessFile forums.oracle.com |
72. random access file forums.oracle.com |
73. RandomAccessFile problem forums.oracle.comHard to say what is happening. It is even hard to say where the problem might originate: it might be a code problem, but more likely it is a configuration problem in the environment (OS) that Java is running in. One thing you can try is using a profiler to seek slow parts in the application. Perhaps that will help you ... |
74. RandomAccessFile help please,thank you forums.oracle.comtwo bytes are written to the file, starting at the current file pointer, as if by the writeShort method giving the number of bytes to follow. This value is the number of bytes actually written out, not the length of the string. Following the length, each character of the string is output, in sequence, using the modified UTF-8 encoding for each ... |
75. Random Access File forums.oracle.comhere is what is listed as what i'm supposed to do with this portion, i may be reading wrong as well you will write a separate class file called SeekFile.java that access the file as a Random Access File. You will index the position of each of the lines and their PMIDs, and create a hash of that data. Again, you ... |
76. Working with RandomAccessFile forums.oracle.comHi everyone, I am in great trouble. I have got an assigment for school and i am not getting any idea how to do it. I would like to manipulate records file so that to be able to add,delete,modify and search. It says: 1). Adding data to an instace of Random Access File class by direct manipulation of the file pointer ... |
77. Binary IO in RandomAccessFile super slow ? forums.oracle.comYou should carefully read the API documentation is the problem here. The issue is what s does in that constructor. And what it does is cause the program to halt and wait for the changes to be flushed to disk fully before continuing. Which means it is extremely slow. I reworked your code into two tests (each wrote 20,000 floats) but ... |
78. What happens to RandomAccessFile when seek operation fails? forums.oracle.com |
79. Dealing with RandomAccessFile, Questions? forums.oracle.com |
80. RandomAccessFile seek question forums.oracle.comWhat in Pattern or Matcher allows you to take a Reader as source and then get the index of the position of a match. You would have to load the whole of the file into memory and work with that which would seem to defeat the point of working with a RandomAccessFile. |
81. Java i/o performance - RandomAccessFile forums.oracle.comI want to improve the RandomAccessFile.write(byte[],int,int) .I don't really know how is implemented by the java sun and how to implement myself to get better performances. All i know(i think i know)is that the java implementation calls the function writeBytes(byte[],int,int) so is somethink like this: public void write(byte[] b, int off, int len){ writeBytes(b,off,len); } I know this because I'm doing ... |
82. Random Access File forums.oracle.comThanks Hunter, I will play around with skpBytes(). Dr, honestly, I really dont want to use random access file. My problem is, i have one big file( > GB), and I was trying to use arrays for that ( if you could recall :)). Then I moved to manupulation with files. The procedure is: big file chunked into number of splits ... |
83. Problem with RandomAccessFile forums.oracle.comcalypso wrote: Im not sure what "raf" is but why not just use FileWriter and FileReader, check this example out below, it uses string but as im sue you know you can convert strings to ints/floats and visa versa.. So now you're advocating that newbies: * use non-standard naming convention: "class fileReaderWriter" * write to file without buffering * close the ... |
84. RandomAccessFile and Cp850 forums.oracle.com |
85. How does a RandomAccessFile work? forums.oracle.comHi everybody, I've read the RandomAccessFile API, and I've never used it before, so there are a few things about it I don't understand, and I'd like to make sure I do before I risk overwriting important bytes or something like that on my computer. So, here are my questions, if anyone would mind answering them. 1. How exactly does the ... |
86. Random Access File forums.oracle.com |
87. Using RandomAccessFile class... forums.oracle.comI want to include the following strings "002, Simon Marshall" and "001, Jackson" into the file and write them on separate lines, instead this is the following output when I write to the file 001, James Smith 002, Stephanie Macintosh 004, Stephanie Macintosh 001, Jane Jones 002, Katrina Martin 002, John Lewis 001, Brenda Jackson 002, Brenda Jackson 002, Lucy Hill002, ... |
88. Read/write On RandomAccessFile .... forums.oracle.comhi i am using a Random Access File as a data storage ... Thus i need to do read and write as well as the delete operations simultaneously... when using synchronized methods no problems at all since only one thread will access at a time ... but when multiple threads will access without synchronized blocks then all will use the same ... |
89. random access file scenario: stuck on how it works? forums.oracle.comIndex File: Assume the hash table will be saved on file when processing is complete and will be entirely restored into memory when processing begins again. Don't use a Random Access File for this. Now what I'm having trouble with is this idea of writing an index file and a data file. So far i've implemented a hash table, which is ... |
90. RandomAccessFile forums.oracle.com |
91. Using RandomAccessFile forums.oracle.com |
92. randomaccessfile or bufferedreader forums.oracle.comHow long does that loop take as opposed to that loop plus your processing? IOW have you established where the bottleneck actually is? - in that loop or in your processing code? I am guessing the latter, and I am further guessing that a judicious use of StringBuffer or StringBuilder will fix it. |
93. File pointer for RandomAccessFile forums.oracle.com |
94. usage of RandomAccessFile. forums.oracle.com |
95. Deleting part of Random Access File in Java forums.oracle.comHey; I am making a program that asks the user all sorts of things about their friends and then stores it in a Random Access File. Then I need to add a delete function that asks for a friend to be deleted and for this I need to know how do I delete an entry if I know where does the ... |
96. RandomAccessFile VS File forums.oracle.com |
97. RandomAccessFile addtion forums.oracle.comHello all, I have a RandomAccessFile of integers. I learnt that when I add a particular integer at a particular position, the number existing at that particular position is being over written with the new one. Isnt there any way to just add the new interger at the position specified without deleting the existing one? Any help would be greatly appreciated ... |
98. RandomAccessFile forums.oracle.com |
99. RandomAccessFile question forums.oracle.comYes, sort of. Or not. In both of them what happens is that bytes are transferred from a piece of hardware (a disk drive) into your program's memory. Or vice versa. At the lowest level there isn't going to be much difference in which tool you use to do that byte-moving. However in sequential reading and writing you may have the ... |
100. ByteInputStream and RandomAccessFile forums.oracle.commy objective is write and read the object to a file using RandomAccessFile concept i can only write the object to a file but i can't read it back please help me... this file(logInfo.log) contain collection of object i want to read all object and my code is private static File file = null; static RandomAccessFile raf = null; . . ... |