file-io

work with text files in java

hi all. I have just started learning java after C + +. but so far nothing is clear. especially the work with classes. tell me please how to open a file for reading or writing? it is desirable to provide the code completely. Thanks. sorry for bad english. upd: I started to learn java hour ago, but has not yet written a working program....

Automatically create directories from long paths

I have a collection of files with fully qualified paths (root/test/thing1/thing2/file.txt). I want to foreach over this collection and drop the file into the location defined in the path, however, if certain directories don't exist, I want them to great created automatically. My program has a default "drop location", such as z:/. The ...

Deleting a line from a file, reading and rewriting is very inefficient ... can someone come up with a better algorithm?

Hi, Deleting a particular line/certain bytes from a file is very inefficient as there is a lot of reading and writing(re-writing) to be done. Is there anyway we can minimize work in such a process? Imagine if an entire file is a set of linked lists and as a user we know the structure of these linked lists then wouldn't it be wonderful a...

File IO doubt in the following code

import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; public class CopyBytes1 { public static void main(String[] args) throws IOException { FileInputStream in = null; FileOutputStream out = null; try { in = new FileInputStream("c:\\aaa.txt"); out ...

c++ fstream concurrent access

What will happen if files are accessed concurrently from different processes/threads? I understand there is no standard way of locking a file, only os specific functions. In my case files will be read often and written seldom. Now if A open a file for reading (ifstream) and starts reading chunks. And B opens the same file for writing (o...

Exception is printed twice

class Patmatch { static String strLine=""; public static void main(String [] args) { try { FileInputStream fstream = new FileInputStream("c://abc.txt"); DataInputStream in = new DataInputStream(fstream); BufferedReader br1 = new BufferedReader(new InputStreamReader(in)); while ((strLine = b...

How to retrieve file names and subdirectory names from a directory in C?

Ok I have something like this: struct dirent *dp; DIR *dir; char fullname[MAXPATHLEN]; char** tmp_paths = argv[1]; //Not the exact code but you get the idea. ... while ((dp = readdir(dir)) != NULL) { struct stat stat_buffer; sprintf(fullname, "%s/%s", *tmp_paths, dp->d_name); if (stat(fullname, &stat_buffer) != 0) ...

Groovy (File IO): find all files and return all files - the Groovy way

Ok, this should be easy... I'm new to groovy and I'm looking to implement the following logic: def testFiles = findAllTestFiles(); So far, I've come up with the code below which successfully prints all files names. However, instead of printing, I just need to put them into a collection. Of course, I could do this the old java way: ...

Smalltalk: Writing output to a file

Usually with my output I am writing it to the Transcript with... Transcript show: How does one write the output to a file instead? ...

php file random access and object to file saving

Hello everyone, I have a csv file with records being sorted on the first field. I managed to generate a function that does binary search through that file, using fseek for random access through file. However, this is still a pretty slow process, since when I seek some file position, I actually need to look left, looking for \n charact...

Odd output from a redefined << operator in c++

Hi all, I am having a runtime error that I can not for the life of me figure out. My program almost does what I want it to, but there are some corrupted characters that print out as gibberish. The program is supposed to take in a text file that represents a forest of trees, build the forest of trees, then traverse the forest to print i...