Renaming file problem

Question

hi
i'm having a problem renaming a file in java.
i'm trying to delete a string from a file and the only thing that seems rationaly to me is to search the string out take the strings before and after and concatinate them into a new file. i'm not sure if this is the best way or the easiest but it seems the most logical to me right now.
the problem now is renaming the temp file into the original file name. how do i do that properly? i've tried renameTo(); but i'm having problems with that i'm getting an invalid IO error.
Please help
Thanks a lot

Answer 1

Hi
I normally use a replace function that I found on this forum earlier this year. If you want to use it on a file you can do it as follows and then there is no need to work with 2 files. (You see that the string that I use for replacement is empty, so in effect it deletes the strings that you don't want.).
import java.io.*;
public class FindReplace {
public static void main (String args[]) {
try {
RandomAccessFile file = new RandomAccessFile("testfile", "rw");
String oString;
String nString;
long len = file.length();
byte[] b = new byte[(int)len];
file.readFully(b);
oString = new String(b);
nString = replace(oString, "old", "", true);
file.seek(0);
file.writeBytes(nString);
// in case the "new file" is shorter than the old one
// truncate the rest of the file, this ensures we don't
// have duplicate content at the end of the file
long nlen = file.getFilePointer();
if (nlen < len) {
file.setLength(nlen);
file.close();
} catch (IOException ioe) {
System.out.println("Error during processing: " + ioe);
public static String replace(String str, String o, String n, boolean all) {
if (str == null || o == null || o.length() == 0 || n == null)
throw new IllegalArgumentException("null or empty String");
StringBuffer result = null;
int oldpos = 0;
do {
int pos = str.indexOf(o, oldpos);
if (pos < 0)
break;
if (result == null)
result = new StringBuffer();
result.append(str.substring(oldpos, pos));
result.append(n);
pos += o.length();
oldpos = pos;
} while (all);
if (oldpos == 0) {
return str;
} else {
result.append(str.substring(oldpos));
return new String(result);
}