Simple find and raplace

Question

Who can please show me the best way to write Say (in /java)
Read a file when java JavaFindReplace.class fileName
is typed in commant line
In JavaFindReplace.class
will be
open file specified
read the file
find everywhere there is "abcd"
and replace with "1234"
End
What is the best way to do this
Thank you

Answer 1

Here's a slightly more complicated search and replace that will replace strings across multiple files of a specified type.
Should serve as a basis for what you want...
package mypackage;
import java.util.*;
import java.io.*;
public class FindReplaceApp
private static void _createFileList(ArrayList list)
File root = new File(ROOT);
File[] files = root.listFiles(new FileFilter());
for (int i=0; i<files.length; i++)
list.add(files);
public static void main(String[] args)
try
java.util.ArrayList files = new ArrayList();
_createFileList(files);
for (int i=0; i<files.size(); i++)
File aFile = (File)files.get(i);
BufferedReader reader = new BufferedReader(new FileReader(aFile));
BufferedWriter writer = new BufferedWriter(new FileWriter(OUTPUT + "\\" + aFile.getName()));
String line = reader.readLine();
while (line != null)
line = line.replaceAll(FIND, REPLACE);
writer.write(line);
writer.newLine();
line = reader.readLine();
reader.close();
writer.flush();
writer.close();
catch (Throwable t)
t.printStackTrace();
private static class FileFilter implements FilenameFilter
public boolean accept(File file, String name)
if ((name.toLowerCase().endsWith(_htmExt)) ||
(name.toLowerCase().endsWith(_htmlExt)))
return true;
return false;
private String _htmExt = ".htm";
private String _htmlExt = ".html";
public static final String ROOT = "C:\\Documents and Settings\\Neil\\My Documents\\webpages\\AdamJoel\\pages";
public static final String OUTPUT = "C:\\Documents and Settings\\Neil\\My Documents\\webpages\\AdamJoel\\newpages";
public static final String FIND = "slide changes every 10 seconds";
public static final String REPLACE = "slide changes every few seconds";