Copying files from one directory to another in Java

Question

I want to copy files from one directory to another  subdirectory  using Java  I have a directory  dir  with text files  I iterate over the first 20 files in dir  and want to copy them to another directory in the dir directory  which I have created right before the iteration  In the code  I want to copy the review  which represents the ith text file or review  to trainingDir  How can I do this  There seems not to be such a function  or I couldn t find   Thank you   boolean success   false  File   reviews   dir listFiles    String trainingDir   dir getAbsolutePath       trainingData   File trDir   new File trainingDir   success   trDir mkdir    for int i   1  i  lt   20  i          File review   reviews i

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Copy file from one directory to another directory     FileChannel source new FileInputStream new File  source file path    getChannel    FileChannel desti new FileOutputStream new File  destination file path    getChannel    desti transferFrom source  0  source size     source close    desti close

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If you don t want to use external libraries and you want to use the java io instead of java nio classes  you can use this concise method to copy a folder and all its content          Copies a folder and all its content to another folder  Do not include file separator at the end path of the folder destination      param folderToCopy The folder and it s content that will be copied     param folderDestination The folder destination     public static void copyFolder File folderToCopy  File folderDestination        if  folderDestination isDirectory       folderToCopy isDirectory            throw new IllegalArgumentException  The folderToCopy and folderDestination must be directories         folderDestination mkdirs         for File fileToCopy   folderToCopy listFiles              File copiedFile   new File folderDestination   File separator   fileToCopy getName              try  FileInputStream fis   new FileInputStream fileToCopy                FileOutputStream fos   new FileOutputStream copiedFile                  int read              byte   buffer   new byte 512                while   read   fis read buffer      -1                    fos write buffer  0  read                           catch  FileNotFoundException e                e printStackTrace              catch  IOException e                e printStackTrace              catch  Exception e                e printStackTrace

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I provided an alternate solution without the need to use a third party  such as apache FileUtils  This can be done through the command line    I tested this out on Windows and it works for me  A Linux solution follows   Here I am utilizing Windows xcopy command to copy all files including subdirectories  The parameters that I pass are defined as per below     e - Copies all subdirectories  even if they are empty   i - If Source is a directory or contains wildcards and Destination does not exist  xcopy assumes Destination specifies a directory name and creates a new directory  Then  xcopy copies all specified files into the new directory   h - Copies files with hidden and system file attributes  By default  xcopy does not copy hidden or system files   My example s  utilizes the ProcessBuilder class to construct a process to execute the copy xcopy  amp  cp  commands   Windows   String src    C   srcDir   String dest    C   destDir   List lt String gt  cmd   Arrays asList  xcopy   src  dest    e     i     h    try       Process proc   new ProcessBuilder cmd  start        BufferedReader inp   new BufferedReader new InputStreamReader proc getInputStream          String line   null      while   line   inp readLine       null            System out println line           catch  IOException e        e printStackTrace        Linux   String src    srcDir    String dest      destDir    List lt String gt  cmd   Arrays asList   bin bash    -c    cp    r   src  dest   try       Process proc   new ProcessBuilder cmd  start        BufferedReader inp   new BufferedReader new InputStreamReader proc getInputStream          String line   null      while   line   inp readLine       null            System out println line           catch  IOException e        e printStackTrace          Or a combo that can work on both Windows or Linux environments   private static final String OS   System getProperty  os name    private static String src   null  private static String dest   null  private static List lt String gt  cmd   null   public static void main String   args        if  OS toLowerCase   contains  windows         setup WINDOWS environment         src    C   srcDir           dest    C   destDir           cmd   Arrays asList  xcopy   src  dest    e     i     h             System out println  on      OS         else if  OS toLowerCase   contains  linux        setup LINUX environment         src    srcDir            dest      destDir            cmd   Arrays asList   bin bash    -c    cp    r   src  dest            System out println  on      OS              try           Process proc   new ProcessBuilder cmd  start            BufferedReader inp   new BufferedReader new InputStreamReader proc getInputStream              String line   null          while   line   inp readLine       null                System out println line                   catch  IOException e            e printStackTrace

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you use renameTo       not obvious  I know     but it s the Java equivalent of move

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Java 8 Path sourcepath   Paths get  quot C   data  temp  mydir quot    Path destinationepath   Paths get  quot C   data  temp  destinationDir quot            Files walk sourcepath            forEach source - gt  copy source  destinationepath resolve sourcepath relativize source        Copy Method static void copy Path source  Path dest        try           Files copy source  dest  StandardCopyOption REPLACE EXISTING         catch  Exception e            throw new RuntimeException e getMessage    e

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import java io File  import java io FileInputStream  import java io FileOutputStream  import java io IOException  import java io InputStream  import java io OutputStream   public class CopyFiles       private File targetFolder      private int noOfFiles      public void copyDirectory File sourceLocation  String destLocation              throws IOException           targetFolder   new File destLocation           if  sourceLocation isDirectory                  if   targetFolder exists                      targetFolder mkdir                               String   children   sourceLocation list                for  int i   0  i  lt  children length  i                      copyDirectory new File sourceLocation  children i                            destLocation                            else                InputStream in   new FileInputStream sourceLocation               OutputStream out   new FileOutputStream targetFolder         sourceLocation getName    true               System out println  Destination Path     targetFolder         sourceLocation getName                                Copy the bits from instream to outstream             byte   buf   new byte 1024               int len              while   len   in read buf    gt  0                    out write buf  0  len                             in close                out close                noOfFiles                         public static void main String   args  throws IOException            File srcFolder   new File  C   sourceLocation              String destFolder   new String  C   targetLocation              CopyFiles cf   new CopyFiles            cf copyDirectory srcFolder  destFolder           System out println  No Of Files got Retrieved from Source     cf noOfFiles           System out println  Successfully Retrieved

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Apache commons FileUtils will be handy  if you want only to move files from the source to target directory rather than copy the whole directory  you can do   for  File srcFile  srcDir listFiles          if  srcFile isDirectory              FileUtils copyDirectoryToDirectory srcFile  dstDir         else           FileUtils copyFileToDirectory srcFile  dstDir             If you want to skip directories  you can do   for  File srcFile  srcDir listFiles          if   srcFile isDirectory              FileUtils copyFileToDirectory srcFile  dstDir

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The example below from Java Tips is rather straight forward   I have since switched to Groovy for operations dealing with the file system - much easier and elegant   But here is the Java Tips one I used in the past  It lacks the robust exception handling that is required to make it fool-proof      public void copyDirectory File sourceLocation   File targetLocation      throws IOException            if  sourceLocation isDirectory                  if   targetLocation exists                      targetLocation mkdir                               String   children   sourceLocation list                for  int i 0  i lt children length  i                      copyDirectory new File sourceLocation  children i                            new File targetLocation  children i                             else                InputStream in   new FileInputStream sourceLocation               OutputStream out   new FileOutputStream targetLocation                   Copy the bits from instream to outstream             byte   buf   new byte 1024               int len              while   len   in read buf    gt  0                    out write buf  0  len                             in close                out close

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apache commons Fileutils is handy  you can do below activities   copying file from one directory to another directory  use copyFileToDirectory File srcFile  File destDir   copying directory from one directory to another directory  use copyDirectory File srcDir  File destDir   copying contents of one file to another use static void copyFile File srcFile  File destFile

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If you want to copy a file and not move it you can code like this   private static void copyFile File sourceFile  File destFile          throws IOException       if   sourceFile exists              return            if   destFile exists              destFile createNewFile              FileChannel source   null      FileChannel destination   null      source   new FileInputStream sourceFile  getChannel        destination   new FileOutputStream destFile  getChannel        if  destination    null  amp  amp  source    null            destination transferFrom source  0  source size               if  source    null            source close              if  destination    null            destination close

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following code to copy files from one directory to another  File destFile   new File targetDir getAbsolutePath     File separator       file getName     try     showMessage  Copying     file getName       in   new BufferedInputStream new FileInputStream file      out   new BufferedOutputStream new FileOutputStream destFile      int n    while   n   in read       -1        out write n         showMessage  Copied     file getName       catch  Exception e      showMessage  Cannot copy file     file getAbsolutePath       finally     if  in    null      try         in close          catch  Exception e            if  out    null      try         out close          catch  Exception e

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In Java 7  there is a standard method to copy files in java    Files copy     It integrates with O S native I O for high performance     See my A on Standard concise way to copy a file in Java  for a full description of usage

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Below is Brian s modified code which copies files from source location to destination location   public class CopyFiles    public static void copyFiles File sourceLocation   File targetLocation      throws IOException            if  sourceLocation isDirectory                  if   targetLocation exists                      targetLocation mkdir                              File   files   sourceLocation listFiles                for File file files                   InputStream in   new FileInputStream file                   OutputStream out   new FileOutputStream targetLocation     file getName                         Copy the bits from input stream to output stream                 byte   buf   new byte 1024                   int len                  while   len   in read buf    gt  0                        out write buf  0  len                                     in close                    out close

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You seem to be looking for the simple solution  a good thing    I recommend using Apache Common s FileUtils copyDirectory      Copies a whole directory to a new   location preserving the file dates       This method copies the specified   directory and all its child   directories and files to the specified   destination  The destination is the   new location and name of the   directory       The destination directory is created   if it does not exist  If the   destination directory did exist  then   this method merges the source with the   destination  with the source taking   precedence    Your code could like nice and simple like this   File trgDir   new File   tmp myTarget     File srcDir   new File   tmp mySource      FileUtils copyDirectory srcDir  trgDir

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There is no file copy method in the Standard API  yet   Your options are    Write it yourself  using a FileInputStream  a FileOutputStream and a buffer to copy bytes from one to the other - or better yet  use FileChannel transferTo    User Apache Commons  FileUtils Wait for NIO2 in Java 7

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Use        org apache commons io FileUtils    It s so handy

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For now this should solve your problem  File source   new File  H   work-temp  file    File dest   new File  H   work-temp  file2    try       FileUtils copyDirectory source  dest     catch  IOException e        e printStackTrace        FileUtils class from apache commons-io library  available since version 1 2   Using third party tools instead of writing all utilities by ourself seems to be a better idea  It can save time and other valuable resources

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File dir   new File  D   mital  filestore    File   files   dir listFiles new File Filter      strLine      txt     for  File file   files           System out println file getName          try           String sourceFile dir      file getName            String destinationFile  D   mital  storefile    file getName            FileInputStream fileInputStream   new FileInputStream sourceFile           FileOutputStream fileOutputStream   new FileOutputStream                          destinationFile           int bufferSize          byte   bufffer   new byte 512           while   bufferSize   fileInputStream read bufffer    gt  0                fileOutputStream write bufffer  0  bufferSize                     fileInputStream close            fileOutputStream close          catch  Exception e            e printStackTrace

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i use the following code to transfer a uploaded CommonMultipartFile to a folder and copy that file to a destination folder in webapps  i e  web project folder       String resourcepath    C  resources images     commonsMultipartFile getOriginalFilename         File file   new File resourcepath       commonsMultipartFile transferTo file          Copy File to a Destination folder     File destinationDir   new File  C  Tomcat webapps myProject resources images         FileUtils copyFileToDirectory file  destinationDir

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The NIO classes make this pretty simple    http   www javalobby org java forums t17036 html

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here is simply a java code to copy data from one folder to another  you have to just give the input of the source and destination   import java io     public class CopyData   static String source  static String des   static void dr File fl boolean first  throws IOException       if fl isDirectory                  createDir fl getPath   first           File flist   fl listFiles            for int i 0 i lt flist length i                           if flist i  isDirectory                                  dr flist i  false                              else                                copyData flist i  getPath                                        else               copyData fl getPath              private static void copyData String name  throws IOException            int i          String str des          for i source length   i lt name length   i                          str str name charAt i                     System out println str           FileInputStream fis new FileInputStream name           FileOutputStream fos new FileOutputStream str           byte   buffer   new byte 1024           int noOfBytes   0           while   noOfBytes   fis read buffer      -1                 fos write buffer  0  noOfBytes                   private static void createDir String name  boolean first         int i       if first  true                for i name length  -1 i gt 0 i--                        if name charAt i   92                                break                                   for  i lt name length   i                          des des name charAt i                       else               String str des          for i source length   i lt name length   i                          str str name charAt i                      new File str   mkdirs              public static void main String args    throws IOException       BufferedReader br new BufferedReader new InputStreamReader System in        System out println  program to copy data from source to destination  n        System out print  enter source path           source br readLine        System out print  enter destination path           des br readLine        long startTime   System currentTimeMillis        dr new File source  true       long endTime     System currentTimeMillis        long time endTime-startTime      System out println   n n Time taken     time   mili sec           this a working code for what you want  let me know if it helped

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File file   fileChooser getSelectedFile        String selected   fc getSelectedFile   getAbsolutePath         File srcDir   new File selected        FileInputStream fii       FileOutputStream fio      try            fii   new FileInputStream srcDir            fio   new FileOutputStream  C   LOvE txt             byte    b new byte 1024            int i 0          try               while   fii read b    gt  0                               System out println b                 fio write b                             fii close                fio close

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import static java nio file StandardCopyOption        Files copy source  target  REPLACE EXISTING     Source   https   docs oracle com javase tutorial essential io copy html

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Not even that complicated and no imports required in Java 7   The renameTo    method changes the name of a file    public boolean renameTo  File destination    For example  to change the name of the file src txt in the current working directory to dst txt  you would write    File src   new File   src txt    File dst   new File   dst txt    src renameTo  dst      That s it    Reference   Harold  Elliotte Rusty  2006-05-16   Java I O  p  393   O Reilly Media  Kindle Edition

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Following recursive function I have written  if it helps anyone  It will copy all the files inside sourcedirectory to destinationDirectory   example   rfunction  D  MyDirectory    D  MyDirectoryNew    D  MyDirectory     public static void rfunction String sourcePath  String destinationPath  String currentPath        File file   new File currentPath       FileInputStream fi   null      FileOutputStream fo   null       if  file isDirectory              String   fileFolderNamesArray   file list            File folderDes   new File destinationPath           if   folderDes exists                  folderDes mkdirs                       for  String fileFolderName   fileFolderNamesArray                rfunction sourcePath  destinationPath         fileFolderName  currentPath         fileFolderName                   else           try               File destinationFile   new File destinationPath                fi   new FileInputStream file               fo   new FileOutputStream destinationPath               byte   buffer   new byte 1024               int ind   0              while   ind   fi read buffer   gt 0                    fo write buffer  0  ind                           catch  FileNotFoundException e                   TODO Auto-generated catch block             e printStackTrace              catch  IOException e                   TODO Auto-generated catch block             e printStackTrace                      finally               if  null    fi                    try                       fi close                      catch  IOException e                           TODO Auto-generated catch block                     e printStackTrace                                                if  null    fo                    try                       fo close                      catch  IOException e                           TODO Auto-generated catch block                     e printStackTrace

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You can use the following code to copy files from one directory to another     parent folders of dest must exist before calling this function public static void copyTo  File src  File dest   throws IOException           recursively copy all the files of src folder if src is a directory      if  src isDirectory                   creating parent folders where source files is to be copied          dest mkdirs             for  File sourceChild   src listFiles                    File destChild   new File  dest  sourceChild getName                   copyTo  sourceChild  destChild                               copy the source file      else            InputStream in   new FileInputStream  src             OutputStream out   new FileOutputStream  dest             writeThrough  in  out             in close             out close

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Spring Framework has many similar util classes like Apache Commons Lang  So there is org springframework util FileSystemUtils   File src   new File   home user src    File dest   new File   home user dest    FileSystemUtils copyRecursively src  dest

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You can use the following code to copy files from one directory to another  public static void copyFile File sourceFile  File destFile  throws IOException           InputStream in   null          OutputStream out   null          try               in   new FileInputStream sourceFile               out   new FileOutputStream destFile               byte   buffer   new byte 1024               int length              while   length   in read buffer    gt  0                    out write buffer  0  length                           catch Exception e               e printStackTrace                      finally               in close                out close

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This prevents file from being corrupted    Just download the following jar  Jar File Download Page  import org springframework util FileCopyUtils   private static void copyFile File source  File dest  throws IOException         This is safe and don t corrupt files as FileOutputStream does     File src   source      File destination   dest      FileCopyUtils copy src  destm

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Inspired by Mohit s answer in this thread  Applicable only for Java 8   The following can be used to copy everything recursively from one folder to another   public static void main String   args  throws IOException       Path source   Paths get   path to source dir        Path destination   Paths get   path to dest dir         List lt Path gt  sources   Files walk source  collect toList         List lt Path gt  destinations   sources stream                map source  relativize               map destination  resolve               collect toList          for  int i   0  i  lt  sources size    i              Files copy sources get i   destinations get i              Stream-style FTW   Upd 2019-06-10  important note - close the stream  e g  using try-with-resource  acquired by Files walk call  Thanks to  jannis for the point

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Best way as per my knowledge is as follows       public static void main String   args         String sourceFolder    E   Source       String targetFolder    E   Target       File sFile   new File sourceFolder       File   sourceFiles   sFile listFiles        for  File fSource   sourceFiles            File fTarget   new File new File targetFolder   fSource getName             copyFileUsingStream fSource  fTarget           deleteFiles fSource                private static void deleteFiles File fSource            if fSource exists                  try                   FileUtils forceDelete fSource                 catch  IOException e                    e printStackTrace                                       private static void copyFileUsingStream File source  File dest            InputStream is   null          OutputStream os   null          try               is   new FileInputStream source               os   new FileOutputStream dest               byte   buffer   new byte 1024               int length              while   length   is read buffer    gt  0                    os write buffer  0  length                           catch  Exception ex                System out println  Unable to copy file     ex getMessage               finally               try                   is close                    os close                  catch  Exception ex

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You can workaround with copy the source file to a new file and delete the original   public class MoveFileExample     public static void main String   args            InputStream inStream   null      OutputStream outStream   null       try            File afile   new File  C   folderA  Afile txt            File bfile   new File  C   folderB  Afile txt             inStream   new FileInputStream afile           outStream   new FileOutputStream bfile            byte   buffer   new byte 1024            int length            copy the file content in bytes          while   length   inStream read buffer    gt  0                outStream write buffer  0  length                      inStream close            outStream close               delete the original file         afile delete             System out println  File is copied successful            catch IOException e            e printStackTrace

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File sourceFile   new File  C   Users  Demo  Downloads  employee    img   File destinationFile   new File    images      sourceFile getName      FileInputStream fileInputStream   new FileInputStream sourceFile   FileOutputStream fileOutputStream   new FileOutputStream                  destinationFile    int bufferSize  byte   bufffer   new byte 512   while   bufferSize   fileInputStream read bufffer    gt  0        fileOutputStream write bufffer  0  bufferSize     fileInputStream close    fileOutputStream close

[java] Copying files from one directory to another in Java

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