In the program below I'm currently reading files in a directory. However I'd like to only read .txt files. How can I read only the .text files located in the directory.
import java.io.*;
public class Data {
public static void main(String[] args) throws IOException {
String target_dir = "C:\\Files";
String textfile;
File dir = new File(target_dir);
File[] files = dir.listFiles();
for (File textfiles : files) {
if (textfiles.isFile()) {
BufferedReader inputStream = null;
try {
inputStream = new BufferedReader(new FileReader(textfiles));
String line;
while ((line = inputStream.readLine()) != null) {
System.out.println(line);
}
} finally {
if (inputStream != null) {
inputStream.close();
}
}
}
}
}
}
You can use java.io.FilenameFilter to filter files in a directory.
import java.io.*;
public class Data {
public static void main(String[] args) throws IOException {
String target_dir = "C:\\Files";
File dir = new File(target_dir);
FilenameFilter textFileFilter = new FilenameFilter() {
#Override
public boolean accept(File dir, String name) {
return name.endsWith(".txt");
}
};
File[] files = dir.listFiles(textFileFilter);
for (File textfiles : files) {
if (textfiles.isFile()) {
BufferedReader inputStream = null;
try {
inputStream = new BufferedReader(new FileReader(textfiles));
String line;
while ((line = inputStream.readLine()) != null) {
System.out.println(line);
}
} finally {
if (inputStream != null) {
inputStream.close();
}
}
}
}
}
}
Try checking the extension
import java.io.*;
public class Data {
public static void main(String[] args) throws IOException {
String target_dir = "C:\\Files";
String textfile;
File dir = new File(target_dir);
File[] files = dir.listFiles();
for (File textfiles : files) {
if (textfiles.isFile() && textfiles.getName().endsWith(".txt")) {
BufferedReader inputStream = null;
try {
inputStream = new BufferedReader(new FileReader(textfiles));
String line;
while ((line = inputStream.readLine()) != null) {
System.out.println(line);
}
} finally {
if (inputStream != null) {
inputStream.close();
}
}
}
}
}
}
Use Files.probeContentPath() to get a mime of the file.
You can use a FileNameFilter to do that work for you. Your code could look like this:
File[] files = dir.listFiles(new FilenameFilter() {
#Override
public boolean accept(File dir, String name) {
if (name.toLowerCase().endsWith(".txt")) return true;
return false;
}
});
Then you know that files contains only files that end with .txt, or whatever other conditions you need.
I like the DirectoryScanner method which uses ant.jar.
DirectoryScanner scanner = new DirectoryScanner();
scanner.setIncludes(new String[]{"**/*.txt"});
scanner.setBasedir("C:\\Files");
scanner.setCaseSensitive(false);
scanner.scan();
String[] files = scanner.getIncludedFiles();
This is from Misha Here. But as you can see there are many ways to do this.
Write a method that returns all the .txt files in a given directory.
import java.io.File;
import java.io.FilenameFilter;
public class Data {
public File[] finder( String dirName){
File dir = new File(dirName);
return dir.listFiles(new FilenameFilter() {
public boolean accept(File dir, String filename)
{ return filename.endsWith(".txt"); }
} );
}
public static void main(String[] args) throws IOException {
String target_dir = "C:\\Files";
String textfile;
File dir = new File(target_dir);
File[] files = finder(target_dir);
for (File textfiles : files) {
if (textfiles.isFile() && textfiles.getName().endsWith("txt")) {
BufferedReader inputStream = null;
try {
inputStream = new BufferedReader(new FileReader(textfiles));
String line;
while ((line = inputStream.readLine()) != null) {
System.out.println(line);
}
} finally {
if (inputStream != null) {
inputStream.close();
}
}
}
}
}
}
DIR* dir = opendir("."); // to open current dir
entity = readdir(dir);
while(entity != NULL){
sprintf(filename,"%s", entity->d_name);
len = strlen(filename);
if(strcmp(filename+len-4,".txt")) {entity = readdir(dir); continue;}
// operation to execute.
entity = readdir(dir);
}
//like this also we can do this task
Related
So i want my program to write all files containing ".txt" to "out.txt". But wr.close() ends my writer and it only writes the files from one folder and not from all. Need help.
import java.io.*;
public class Prv {
public static void main(String[] args) throws InterruptedException, IOException{
String a=".";
String b="D:\\JavaProjects\\Auditoriski\\.\\Out.txt";
Pomini(a,b);
}
public static void Pomini(String in, String out) throws IOException {
File file = new File(in);
BufferedWriter wr = new BufferedWriter(new FileWriter(out));
if(file.exists()) {
File[] subfiles = file.listFiles();
for(File f : subfiles) {
if(f.isDirectory()) {
Pomini(f.getAbsolutePath(), out );
}
if(f.getName().contains(".txt")) {
System.out.print(f.getName());
System.out.println();
wr.write(f.getName());
wr.newLine();
}
}
}
wr.close();
}
}
You just need to create BufferedWriter and close it outside of your Pomini method and pass it as a parameter.
try (BufferedWriter wr = new BufferedWriter(new FileWriter(out));) {
Pomini(a, b, wr);
}
public static void Pomini(String in, String out, BufferedWriter wr) throws IOException {
File file = new File(in);
if(file.exists()) {
File[] subfiles = file.listFiles();
for(File f : subfiles) {
if(f.isDirectory()) {
Pomini(f.getAbsolutePath(), out, wr);
}
if(f.getName().contains(".txt")) {
System.out.print(f.getName());
System.out.println();
wr.write(f.getName());
wr.newLine();
}
}
}
}
I have a piece of code that iterates over all the files in a directory.
But I am stuck now at reading the content of the file into a String object.
public String filemethod(){
if (path.isDirectory()) {
files = path.list();
String[] ss;
for (int i = 0; i < files.length; i++) {
ss = files[i].split("\\.");
if (files[i].endsWith("txt"))
System.out.println(files[i]);
}
}
return String.valueOf(files);
}
Faced with a similar problem and wrote a code a while back. This will read the content of all files of a directory.
May require adjustments based on your file directories but its tried and tested code.Hope this helps :)
package FileHandling;
import java.io.*;
import java.util.ArrayList;
import java.util.Collections;
public class BufferedInputStreamExample {
FileInputStream fis = null;
BufferedInputStream bis = null;
DataInputStream dis = null;
public void readFile(File folder) {
ArrayList<File> myFiles = listFilesForFolder(folder);
for (File f : myFiles) {
String path = f.getAbsolutePath();
//Path of the file(Optional-You can know which file's content is being printed)
System.out.println(path);
File infile = new File(path);
try {
fis = new FileInputStream(infile);
bis = new BufferedInputStream(fis);
dis = new DataInputStream(bis);
while (dis.available() != 0) {
String line = dis.readLine();
System.out.println(line);
}
} catch (IOException e) {
} finally {
try {
fis.close();
bis.close();
dis.close();
} catch (Exception ex) {
}
}
}
}
public ArrayList<File> listFilesForFolder(final File folder){
ArrayList<File> myFiles = new ArrayList<File>();
for (File fileEntry : folder.listFiles()) {
if (fileEntry.isDirectory()) {
myFiles.addAll(listFilesForFolder(fileEntry));
} else {
myFiles.add(fileEntry);
}
}
return myFiles;
}
}
Main method
package FileHandling;
import java.io.File;
public class Main {
public static void main(String args[]) {
//Your directory here
final File folder = new File("C:\\Users\\IB\\Documents\\NetBeansProjects\\JavaIO\\files");
BufferedInputStreamExample bse = new BufferedInputStreamExample();
bse.readFile(folder);
}
}
I would use following code:
public static Collection<File> allFilesInDirectory(File root) {
Set<File> retval = new HashSet<>();
Stack<File> todo = new Stack<>();
todo.push(root);
while (!todo.isEmpty()) {
File tmp = todo.pop();
if (tmp.isDirectory()) {
for (File child : tmp.listFiles())
todo.push(child);
} else {
if (isRelevantFile(tmp))
retval.add(tmp);
}
}
return retval;
}
All you need then is a method that defines what files are relevant for your usecase (for instance txt)
public static boolean isRelevantFile(File tmp) {
// get the extension
String ext = tmp.getName().contains(".") ? tmp.getName().substring(tmp.getName().lastIndexOf('.') + 1) : "";
return ext.equalsIgnoreCase("txt");
}
Once you have all the files, you can easily get all the text with a little hack in Scanner
public static String allText(File f){
// \\z is a virtual delimiter that marks end of file/string
return new Scanner(f).useDelimiter("\\z").next();
}
So now, using these methods you can easily extract all the text from an entire directory.
public static void main(String[] args){
File rootDir = new File(System.getProperty("user.home"));
String tmp = "";
for(File f : allFilesInDirectory(rootDir)){
tmp += allText(f);
}
System.out.println(tmp);
}
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
public class ReadDataFromFiles {
static final File DIRECTORY = new File("C:\\myDirectory");
public static void main(String[] args) throws IOException {
StringBuilder sb = new StringBuilder();
//append content of each file to sb
for(File f : getTextFiles(DIRECTORY)){
sb.append(readFile(f)).append("\n");
}
System.out.println(sb.toString());
}
// get all txt files from the directory
static File[] getTextFiles(File dir){
FilenameFilter textFilter = (File f, String name) -> name.toLowerCase().endsWith(".txt");
return dir.listFiles(textFilter);
}
// read the content of a file to string
static String readFile(File file) throws IOException{
return new String(Files.readAllBytes(Paths.get(file.getAbsolutePath())), StandardCharsets.UTF_8);
}
}
This question already has answers here:
Standard concise way to copy a file in Java?
(16 answers)
Closed 6 years ago.
I am trying to write a java program that will take two arguments, dirName and fileName. The program will search for all the files in dirName that end with .java and then concatenate them into a new folder called fileName. So far I have a method to search for .java files in dirName, I then put them in a file array called list but now I am struggling to iteratively add the files in this array to my new folder, fileName. Here is what I have so far:
import java.io.File;
import java.io.FileInputStream;
import java.io.FilenameFilter;
import java.util.ArrayList;
public class TwoFiles {
File dir;
File name;
public TwoFiles(File dirName, File fileName) {
dir = dirName;
name = fileName;
}
public void setDir(File m) {
this.dir = m;
}
public File getDir() {
return dir;
}
public void setNewFolder(File n) {
this.name = n;
}
public File getNewFolder() {
return name;
}
public File[] Finder(File dir) {
dir = getDir();
return dir.listFiles(new FilenameFilter() {
public boolean accept(File dir, String filename) {
return name.endsWith(".java"); }
} );
}
public static void main(String[] args) {
File folder = null;
File newFolder = null;
Integer b = null;
TwoFiles tf = new TwoFiles(folder, newFolder);
folder = tf.getDir();
newFolder = tf.getNewFolder();
File[] list = tf.Finder(folder); //add to an array
//here is where I've been experimenting to add files in `list` to new folder, `fileName`.
for (File file : list)
{
FileInputStream inFile = new FileInputStream(file);
while ((b = inFile.read()) != -1)
newFolder.write(b);
inFile.close();
}
//copy files from array (list) into newFolder
}
}
Thanks for your time.
Your newFolder variable is of type File. You cannot write into this. I assume, your code does not even compile. You have to create an output stream in front of your loop:
FileOutputStream fos = new FileOutputStream( newFolder);
try
{
for (File file : list)
{
FileInputStream inFile = new FileInputStream(file);
while ((b = inFile.read()) != -1)
fos.write(b);
inFile.close();
}
}
finally
{
fos.close();
}
You can use the Apache Commons IO copyDirectory() with the IOFileFilter (for .java extensions) to copy your files from one directory to another. Before that you can ensure to create a new directory using forceMkdir() for your filename.
It's my version of your problem:
I created other constructor, where you can put only paths to directory/folder from you want concatenate files, and to file of concatenations result.
public class TwoFiles {
private File dir;
private File name;
public TwoFiles(File dirName, File fileName) {
dir = dirName;
name = fileName;
}
public TwoFiles(String dirName, String destinationFileName) throws IOException{
dir=new File(dirName);
if(!dir.isDirectory()){
throw new FileNotFoundException();//here your exception in case when dirName is file name instead folder name
}
name=new File(destinationFileName);
if(!name.exists()){
name.createNewFile();
}
}
public void setDir(File m) {
this.dir = m;
}
public File getDir() {
return dir;
}
public void setNewFolder(File n) {
this.name = n;
}
public File getNewFolder() {
return name;
}
public void concatenateFiles() throws IOException{
File[] files=dir.listFiles();
for(File file: files){
if(file.getName().endsWith(".java")){ //check is right file
prescribe(name, file);
}
}
}
/** prescribe file to new destination */
private void prescribe(File destination, File file) throws IOException {
FileInputStream inFile = new FileInputStream(file);
FileOutputStream writer=new FileOutputStream(destination, true); //true means next file will be write beginning from end of the file
int x;
while((x=inFile.read())!=-1){
writer.write(x);
}
String test="\n"; //next line in file
writer.write(test.getBytes());
writer.close();
inFile.close();
}
public static void main(String...strings){
String dirName="C/myApp/model/entity";
String fileName="C:/Users/Dell/Desktop/temp/test.java";
try {
new TwoFiles(dirName, fileName).concatenateFiles();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public class FIlesInAFolder {
private static BufferedReader br;
public static void main(String[] args) throws IOException {
File folder = new File("C:/filesexamplefolder");
FileReader fr = null;
if (folder.isDirectory()) {
for (File fileEntry : folder.listFiles()) {
if (fileEntry.isFile()) {
try {
fr = new FileReader(folder.getAbsolutePath() + "\\" + fileEntry.getName());
br = new BufferedReader(fr);
System.out.println(""+br.readLine());
}
catch (FileNotFoundException e) {
e.printStackTrace();
}
finally {
br.close();
fr.close();
}
}
}
}
}
}
how to print the first word from first file of a directory and the second word from second file and third word from a third file of the same directory.
i am able to open directory and print the line from each file of the directory,
but tell me how to print the first word from first file and second word from second file and so on . .
Something like the below will read first word from first file, second word from second file, ... nth word from nth file. You'll likely want to do some additional work to improve the codes stability.
import java.io.File;
import java.io.IOException;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
public class SOAnswer {
private static void printFirst(File file, int offset) throws FileNotFoundException, IOException {
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
String line = null;
while ( (line = br.readLine()) != null ) {
String[] split = line.split(" ");
if(split.length >= offset) {
String targetWord = split[offset];
}
// we do not care if files are read that do not match your requirements, or
// for reading complete files as you only care for the first word
break;
}
br.close();
fr.close();
}
public static void main(String[] args) throws Exception {
File folder = new File(args[0]);
if(folder.isDirectory()) {
int offset = 0;
for(File fileEntry : folder.listFiles()) {
if(fileEntry.isFile()) {
printFirst(fileEntry, offset++); // handle exceptions if you wish
}
}
}
}
}
I am changing names of all files in directory and if it's text file I am changing the content but it doesn't seem to work the name of the file is changed right but content is blank/gone heres is my code:
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import org.apache.commons.io.FilenameUtils;
public class FileOps {
public static File folder = new File(
"C:\\Users\\N\\Desktop\\New folder\\RenamingFiles\\src\\renaming\\Files");
public static File[] listOfFiles = folder.listFiles();
public static void main(String[] argv) throws IOException {
toUpperCase();
}
public static void toUpperCase() throws FileNotFoundException {
for (int i = 0; i < listOfFiles.length; i++) {
if (listOfFiles[i].isFile()) {
String newname = mixCase(listOfFiles[i].getName());
if (listOfFiles[i].renameTo(new File(folder, newname))) {
String extension = FilenameUtils
.getExtension(listOfFiles[i].getName());
if (extension.equals("txt") || extension.equals("pdf")
|| extension.equals("docx")
|| extension.equals("log")) {
rewrite(listOfFiles[i]);
System.out.println("Done");
}
}
} else {
System.out.println("Nope");
}
}
}
public static String mixCase(String in) {
StringBuilder sb = new StringBuilder();
if (in != null) {
char[] arr = in.toCharArray();
if (arr.length > 0) {
char f = arr[0];
boolean first = Character.isUpperCase(f);
for (int i = 0; i < arr.length; i++) {
sb.append((first) ? Character.toLowerCase(arr[i])
: Character.toUpperCase(arr[i]));
first = !first;
}
}
}
return sb.toString();
}
public static void rewrite(File file) throws FileNotFoundException {
FileReader reader = new FileReader(file.getAbsolutePath());
BufferedReader inFile = new BufferedReader(reader);
try {
FileWriter fwriter = new FileWriter(file.getAbsolutePath());
BufferedWriter outw = new BufferedWriter(fwriter);
while (inFile.readLine() != null) {
String line = mixCase(inFile.readLine());
outw.write(line);
}
inFile.close();
outw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
There is several issue with your code:
Your rewrite function is perform on old name File. It should be done on the renamed File:
String newname = mixCase(listOfFiles[i].getName());
File renamedFile = new File(folder, newname);
if (listOfFiles[i].renameTo(renamedFile )) {
String extension = FilenameUtils
.getExtension(listOfFiles[i].getName());
if (extension.equals("txt") || extension.equals("pdf")
|| extension.equals("docx")
|| extension.equals("log")) {
rewrite(renamedFile);
System.out.println("Done");
}
}
you are trying to read docx and pdf file like regular text file. This cannot work. You will have to use external library like POI and pdf Box
Your rewrite function is not safe. You must unsure to close the ressources:
FileReader reader = null;
BufferedReader inFile = null;
try {
reader = new FileReader(file.getAbsolutePath());
inFile = new BufferedReader(reader);
FileWriter fwriter = new FileWriter(file.getAbsolutePath());
BufferedWriter outw = new BufferedWriter(fwriter);
while (inFile.readLine() != null) {
String line = mixCase(inFile.readLine());
outw.write(line);
}
} catch (IOException e) {
e.printStackTrace();
}finally
{
if(infile != null)
inFile.close();
if(reader != null)
reader .close();
}
You can't re-write a file on top of itself. you need to write the new content to a new file, then rename again.