Move Copy File Operations in Java

Question

Is there a standard Java library that handles common file operations such as moving copying files folders

User · Answer

Check out  http   commons apache org io   It has copy  and as stated the JDK already has move   Don t implement your own copy method   There are so many floating out there

User · Answer

Not yet  but the New NIO  JSR 203  will have support for these common operations   In the meantime  there are a few things to keep in mind   File renameTo generally works only on the same file system volume  I think of this as the equivalent to a  mv  command  Use it if you can  but for general copy and move support  you ll need to have a fallback   When a rename doesn t work you will need to actually copy the file  deleting the original with File delete if it s a  move  operation   To do this with the greatest efficiency  use the FileChannel transferTo or FileChannel transferFrom methods  The implementation is platform specific  but in general  when copying from one file to another  implementations avoid transporting data back and forth between kernel and user space  yielding a big boost in efficiency

User · Answer

Check out  http   commons apache org io   It has copy  and as stated the JDK already has move   Don t implement your own copy method   There are so many floating out there

User · Answer

Try to use org apache commons io FileUtils  General file manipulation utilities   Facilities are provided in the following methods        1  FileUtils moveDirectory File srcDir  File destDir     Moves a   directory        2  FileUtils moveDirectoryToDirectory File src  File destDir  boolean   createDestDir     Moves a directory to another directory        3  FileUtils moveFile File srcFile  File destFile     Moves a file        4  FileUtils moveFileToDirectory File srcFile  File destDir  boolean   createDestDir     Moves a file to a directory        5  FileUtils moveToDirectory File src  File destDir  boolean   createDestDir     Moves a file or directory to the destination   directory    It s simple  easy and fast

User · Answer

Check out  http   commons apache org io   It has copy  and as stated the JDK already has move   Don t implement your own copy method   There are so many floating out there

User · Answer

Here s how to do this with java nio operations   public static void copyFile File sourceFile  File destFile  throws IOException       if  destFile exists              destFile createNewFile               FileChannel source   null      FileChannel destination   null      try           source   new FileInputStream sourceFile  getChannel            destination   new FileOutputStream destFile  getChannel                previous code  destination transferFrom source  0  source size                to avoid infinite loops  should be          long count   0          long size   source size                          while  count    destination transferFrom source  count  size-count   lt size             finally           if source    null                source close                      if destination    null                destination close

User · Answer

Google s Guava library also has these   http   guava-libraries googlecode com svn trunk javadoc com google common io Files html

User · Answer

Check out  http   commons apache org io   It has copy  and as stated the JDK already has move   Don t implement your own copy method   There are so many floating out there

User · Answer

Not yet  but the New NIO  JSR 203  will have support for these common operations   In the meantime  there are a few things to keep in mind   File renameTo generally works only on the same file system volume  I think of this as the equivalent to a  mv  command  Use it if you can  but for general copy and move support  you ll need to have a fallback   When a rename doesn t work you will need to actually copy the file  deleting the original with File delete if it s a  move  operation   To do this with the greatest efficiency  use the FileChannel transferTo or FileChannel transferFrom methods  The implementation is platform specific  but in general  when copying from one file to another  implementations avoid transporting data back and forth between kernel and user space  yielding a big boost in efficiency

User · Answer

Google s Guava library also has these   http   guava-libraries googlecode com svn trunk javadoc com google common io Files html

User · Answer

Not yet  but the New NIO  JSR 203  will have support for these common operations   In the meantime  there are a few things to keep in mind   File renameTo generally works only on the same file system volume  I think of this as the equivalent to a  mv  command  Use it if you can  but for general copy and move support  you ll need to have a fallback   When a rename doesn t work you will need to actually copy the file  deleting the original with File delete if it s a  move  operation   To do this with the greatest efficiency  use the FileChannel transferTo or FileChannel transferFrom methods  The implementation is platform specific  but in general  when copying from one file to another  implementations avoid transporting data back and forth between kernel and user space  yielding a big boost in efficiency

User · Answer

Here s how to do this with java nio operations   public static void copyFile File sourceFile  File destFile  throws IOException       if  destFile exists              destFile createNewFile               FileChannel source   null      FileChannel destination   null      try           source   new FileInputStream sourceFile  getChannel            destination   new FileOutputStream destFile  getChannel                previous code  destination transferFrom source  0  source size                to avoid infinite loops  should be          long count   0          long size   source size                          while  count    destination transferFrom source  count  size-count   lt size             finally           if source    null                source close                      if destination    null                destination close

User · Answer

Previous answers seem to be outdated    Java s File renameTo   is probably the easiest solution for API 7  and seems to work fine  Be carefull IT DOES NOT THROW EXCEPTIONS  but returns true false     Note that there seem to be problems with it  in previous versions  same as NIO     If you need to use a previous version  check here   Here s an example for API7   File f1  new File  C   Users         foo    File f2  new File  C   Users          foo old    System err println  Result of move   f1 renameTo f2      Alternatively   System err println  Move    f1 toURI     --- gt  gt  gt  gt   f2 toURI     Path b1 Files move f1 toPath     f2 toPath    StandardCopyOption ATOMIC MOVE  StandardCopyOption REPLACE EXISTING      System err println  Move  RETURNS   b1

User · Answer

Try to use org apache commons io FileUtils  General file manipulation utilities   Facilities are provided in the following methods        1  FileUtils moveDirectory File srcDir  File destDir     Moves a   directory        2  FileUtils moveDirectoryToDirectory File src  File destDir  boolean   createDestDir     Moves a directory to another directory        3  FileUtils moveFile File srcFile  File destFile     Moves a file        4  FileUtils moveFileToDirectory File srcFile  File destDir  boolean   createDestDir     Moves a file to a directory        5  FileUtils moveToDirectory File src  File destDir  boolean   createDestDir     Moves a file or directory to the destination   directory    It s simple  easy and fast

User · Answer

Previous answers seem to be outdated    Java s File renameTo   is probably the easiest solution for API 7  and seems to work fine  Be carefull IT DOES NOT THROW EXCEPTIONS  but returns true false     Note that there seem to be problems with it  in previous versions  same as NIO     If you need to use a previous version  check here   Here s an example for API7   File f1  new File  C   Users         foo    File f2  new File  C   Users          foo old    System err println  Result of move   f1 renameTo f2      Alternatively   System err println  Move    f1 toURI     --- gt  gt  gt  gt   f2 toURI     Path b1 Files move f1 toPath     f2 toPath    StandardCopyOption ATOMIC MOVE  StandardCopyOption REPLACE EXISTING      System err println  Move  RETURNS   b1

User · Answer

Not yet  but the New NIO  JSR 203  will have support for these common operations   In the meantime  there are a few things to keep in mind   File renameTo generally works only on the same file system volume  I think of this as the equivalent to a  mv  command  Use it if you can  but for general copy and move support  you ll need to have a fallback   When a rename doesn t work you will need to actually copy the file  deleting the original with File delete if it s a  move  operation   To do this with the greatest efficiency  use the FileChannel transferTo or FileChannel transferFrom methods  The implementation is platform specific  but in general  when copying from one file to another  implementations avoid transporting data back and forth between kernel and user space  yielding a big boost in efficiency

User · Answer

Interesting observation  Tried to copy the same file via various java classes and printed time in nano seconds   Duration using FileOutputStream byte stream  4 965 078  Duration using BufferedOutputStream  1 237 206  Duration using  character text Reader  2 858 875  Duration using BufferedReader Buffered character text stream  1 998 005  Duration using  Files NIO copy   18 351 115  when using Files Nio copy option it took almost 18 times longer    Nio is the slowest option to copy files and BufferedOutputStream looks like the fastest  I used the same simple text file for each class

User · Answer

Interesting observation  Tried to copy the same file via various java classes and printed time in nano seconds   Duration using FileOutputStream byte stream  4 965 078  Duration using BufferedOutputStream  1 237 206  Duration using  character text Reader  2 858 875  Duration using BufferedReader Buffered character text stream  1 998 005  Duration using  Files NIO copy   18 351 115  when using Files Nio copy option it took almost 18 times longer    Nio is the slowest option to copy files and BufferedOutputStream looks like the fastest  I used the same simple text file for each class

[java] Move / Copy File Operations in Java

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