How to Merge and split a file

[kewlkeny]

Hello, Can any one please tell me how to merge two text files into a another text file and how to split a huge data text file in to small chunks ? Thnank you :)

[ozzyman]

Read both files, create a new file and write the content from both to it.

Or in the second case, read the content of one file, query the length, copy the first half to one string and the second half to another string and then write both strings to separate files.

You could use FileReader and FileWriter to read and write to a file.

[Tolls]

For the second case, assuming you have some sort of idea of where you are breaking (some specific bit of text to look for, or number of lines) then read and write at the same time. There is no need to store more than a single line in memory for that job.

Open file reader
Open file writer
for each line {
    write line
    if current output is complete {
        close file writer
        open new file writer (to new file)
    }
}
close file writer
clode file reader

[kewlkeny]

Thank you for the reply .

Can you please tell me how to merge and split the files with the same memory size, for example i have a few no of file with different sizes, now i want merge and split them into same memory !!!

Thank you

[Tolls]

Without knowing why, or what it is you are actually trying to do, or the contents of the files, that's almost impossible to answer.

You can get the size of a file (length()) and use that if you read byte by byte. However, that'll probably destroy any useful information in the file as few things neatly fit into a single byte.

[clydedoris]

this is some kind of weird programming task. would you also mind sharing what you are trying to accomplish?

[kewlkeny]

public class FileSpltr {

static Logger logger = LoggerFactory.getLogger(FileSpltr.class);

public void FileSplitter(String source, String destination, long size) throws IOException{

File file = new File(source);
FileInputStream fis = new FileInputStream(file);
long fsize = file.length();
logger.debug("main file size is" + " " + fsize);

long sepsize = fsize / size;
long mod = fsize % size;
if (mod != 0) {
sepsize++;
}
for (int i = 0; i < sepsize; i++) {
String str;
str = i + " ";
FileOutputStream fos = new FileOutputStream(
destination + str + ".");

logger.info("FOS" + destination);

out: for (long j = 0; j < size; j++) {
int ch;
ch = fis.read();
if (ch == -1)
break out;
fos.write(ch);

}
fos.close();
}
fis.close();

logger.info("Splitted the file to splitted Folder");
}
}


This is the code it will work to split the file in equal size of chunks

[kewlkeny]

And for merging of files

public class FileMergr {
static Logger logger = LoggerFactory.getLogger(FileMergr.class);

public void mergeFiles(String source, String destin) throws IOException{
PrintWriter pw = new PrintWriter(new FileOutputStream(
destin));

File file = new File(source);
File[] files = file.listFiles();
for (int i = 0; i < files.length; i++) {

logger.debug("Processing " + files[i].getPath() + "... ");
BufferedReader br = new BufferedReader(new FileReader(
files[i].getPath()));
String line = br.readLine();
while (line != null) {
pw.println(line);
line = br.readLine();
}

br.close();
}
pw.close();
logger.info("Merged the files of temporary folder to Merged Folder"
+ destin);
}
}