Issue: bunch of files name file_0001.dat, file_0002.dat......file_1000.dat.
I want to change the file names such as the number after file_ will be a
multiple of 4 in comparison to previous file name. So i want to change
file_0001.dat to file_0004.dat
file_0002.dat to file_0008.dat Start from the highest and go to lowest. As
if u go from lowest - there will be conflicts. example u cant rename 001
to 004 if there is a 004 from before ...what if it at first you have
file_0001.dat, file_0001.dat, ... file_0004.dat. import java.util.*;
import java.io.*;
public class RenameFiles{
private Properties props = new Properties();
private String args[];
private TreeMap<Integer, FileRen> ffs = new TreeMap<Integer, FileRen>();
RenameFiles(String args[]){
this.args = args;
start();
}
public static void main(String args[]){
new RenameFiles(args);
}
void start(){
defaults();
load();
scanDir();
renameDo();
}
void renameDo(){
final int ll = ffs.size();
if(ll < 1){
System.err.println( "Nothing to do ffs size " + ll );
return;
}
ArrayList<FileRen> frs = new ArrayList<FileRen>();
frs.addAll(ffs.values());
for(int i = ll - 1;i >= 0; i--){
FileRen fr = frs.get(i);
boolean t = fr.orig.renameTo(fr.renamed);
System.err.println(i + " Result " + t + " " + fr.orig + " to " + fr.renamed);
}
}
void load(){
if(args.length > 1){
}
}
void defaults(){
props.setProperty("dir", ".");
}
void scanDir(){
File f = new File(props.getProperty("dir"));
FFilter ffilter = new FFilter();
String []l = f.list(ffilter);
for(String nn : l){
FileRen fr = FileRen.check(f, nn);
if(fr != null){
ffs.put(fr.idx, fr);
}
}
}
}
class FFilter implements java.io.FilenameFilter
{
public boolean accept(File dir,
String name){
System.err.println(dir + " " + name + " check ");
File f = new File(dir, name);
if(!f.exists() || !f.isFile())return false;
final int i = name.lastIndexOf(".");
final int i2 = name.lastIndexOf("_");
if(i2 < 0 || i < i2)return false;
return true;
}
}
class FileRen{
File orig;
File renamed;
int idx;
FileRen(){
}
static FileRen check(File parent, String s){
final int i = s.lastIndexOf(".");
final int i2 = s.lastIndexOf("_");
//file_0001.dat to file_0004.dat
if(i2 < 0 || i < i2)return null;
String p = s.substring(i2+1, i);
try{
int idx = Integer.parseInt(p);
if(idx > 0){
FileRen f = new FileRen();
f.orig = new File(parent, s);
f.idx = idx;
int nxt = idx * 4;
String pad = pad(nxt, 4);
f.renamed = new File(parent, s.substring(0, i2 + 1) + pad +s.substring(i) );
return f;
}
}catch(Exception e){
System.err.println(e + " " + parent + " " + s);
}
return null;
}
static String pad(int i, int k){
StringBuilder sb = new StringBuilder().append(i);
int ll = sb.length();
for(int c = ll; c <= k; c++){
sb.insert(0, '0');
}
return sb.toString();
}
} touch file_0001.dat
touch file_0002.dat
touch file_0004.dat
touch file_0005.dat
touch file_0007.dat
This version just start the program in the same dir as the files, after compiling and changing the classpathjavac /prog/j/apps/sel2in/ioFiles/RenameFiles.java
java -cp /prog/j/apps/sel2in/ioFiles/ RenameFiles
