Java - Search for files in a directory

Question

This is supposed to be simple  but I can t get it -  Write a program that searches for a particular file name in a given directory   I ve found a few examples of a hardcoded filename and directory  but I need both the dir and file name to be as entered by the user   public static void main String   args        String fileName   args 0      For the filename declaration     String directory           boolean found       File dir   new File directory        File   matchingFiles   dir listFiles new FilenameFilter             public boolean accept File dir  String fileName                return true

User · Answer

With   Java 8  there is an alternative that use streams and lambdas   public static void recursiveFind Path path  Consumer lt Path gt  c      try  DirectoryStream lt Path gt  newDirectoryStream   Files newDirectoryStream path         StreamSupport stream newDirectoryStream spliterator    false                    peek p - gt                       c accept p                      if  p toFile                            isDirectory                           recursiveFind p  c                                                              collect Collectors toList         catch  IOException e        e printStackTrace            So this will print all the files recursively   recursiveFind Paths get       System out  println     And this will search for a file   recursiveFind Paths get       p - gt       if  p toFile   getName   toString   equals  src          System out println p

User · Answer

If you want to use a dynamic filename filter you can implement FilenameFilter and pass in the constructor the dynamic name   Of course this implies taht you must instantiate every time the class  overhead   but it works  Example    public class DynamicFileNameFilter implements FilenameFilter        private String comparingname       public DynamicFileNameFilter String comparingName           this comparingname   comparingName              Override     public boolean accept File dir  String name            File file   new File name            if  name equals comparingname   amp  amp   file isDirectory                return false           else             return true             then you use where you need   FilenameFilter fileNameFilter   new DynamicFileNameFilter  thedynamicNameorpatternYouAreSearchinfor    File   matchingFiles   dir listFiles fileNameFilter

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This method will recursively search thru each directory starting at the root  until the fileName is found  or all remaining results come back null   public static String searchDirForFile String dir  String fileName        File   files   new File dir  listFiles        for File f files            if f isDirectory                  String loc   searchDirForFile f getPath    fileName               if loc    null                  return loc                    if f getName   equals fileName               return f getPath              return null

User · Answer

you can try something like this   import java io    import java util    class FindFile        public void findFile String name File file                File   list   file listFiles            if list  null          for  File fil   list                        if  fil isDirectory                                  findFile name fil                             else if  name equalsIgnoreCase fil getName                                   System out println fil getParentFile                                       public static void main String   args                 FindFile ff   new FindFile            Scanner scan   new Scanner System in           System out println  Enter the file to be searched                String name   scan next            System out println  Enter the directory where to search             String directory   scan next            ff findFile name new File directory              Here is the output   J  Java misc load gt java FindFile Enter the file to be searched   FindFile java Enter the directory where to search j  java  FindFile java Found in- gt j  java misc load

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The Following code helps to search for a file in directory and open its location  import java io    import java util    import java awt Desktop  public class Filesearch2         public static void main String   args throws IOException                   Filesearch2 fs   new Filesearch2            Scanner scan   new Scanner System in           System out println  Enter the file to be searched                String name   scan next            System out println  Enter the directory where to search             String directory   scan next            fs findFile name new File directory              public void findFile String name File file1 throws IOException                     File   list   file1 listFiles                   if list  null                                             for File file2   list                                    if  file2 isDirectory                                  findFile name file2                                          else if  name equalsIgnoreCase file2 getName                                                                                                 System out println  Found                                    System out println  File found at     file2 getParentFile                     System out println  Path diectory    file2 getAbsolutePath                     String p1      file2 getParentFile                    File f2   new File p1                   Desktop getDesktop   open f2

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I tried many ways to find the file type I wanted  and here are my results when done  public static void main  String args     final String dir2   System getProperty  quot user name quot      get user name  String path    quot C   Users   quot    dir2   digFile new File path       path is file start to dig         for  int i   0  i  lt  StringFile size    i                   System out println StringFile get i                       private void digFile File dir         FilenameFilter filter   new FilenameFilter             public boolean accept File dir  String name                return name endsWith  quot  mp4 quot                               String   children   dir list filter            if  children    null            return        else           for  int i   0  i  lt  children length  i                  StringFile add dir  quot    quot  children i                          File   directories      directories   dir listFiles new FileFilter              Override         public boolean accept File file                return file isDirectory                           public boolean accept File dir  String name                return  name endsWith  quot  mp4 quot                                  if directories  null              for  File directory   directories               digFile directory

User · Answer

This looks like a homework question  so I ll just give you a few pointers   Try to give good distinctive variable names  Here you used  fileName  first for the directory  and then for the file  That is confusing  and won t help you solve the problem  Use different names for different things   You re not using Scanner for anything  and it s not needed here  get rid of it   Furthermore  the accept method should return a boolean value  Right now  you are trying to return a String  Boolean means that it should either return true or false  For example return a  gt  0  may return true or false  depending on the value of a  But return fileName  will just return the value of fileName  which is a String

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I have used a different approach to search for a file using stack   keeping in mind that there could be folders inside a folder  Though its not faster than windows search and I was not expecting that though  but it definitely gives out correct result  Please modify the code as you wish to  This code was originally made to extract the file path of certain file extension     Feel free to optimize   import java io File  import java io IOException  import java util ArrayList  import java util List           author Deepankar Sinha     public class GetList       public List lt String gt  stack      static List lt String gt  lnkFile      static List lt String gt  progName       int index -1      public static void main String args    throws IOException                  var-- progFile Location of the file to be search           String progFile  C              GetList obj new GetList            String temp progFile          int i          while    amp      equals temp                         File dir new File temp               String   directory dir list                if directory  null               for String name  directory                                if new File temp name  isDirectory                        obj push temp name                        else                     if new File temp name  isFile                                                  try                                  exe can be replaced with file name to be searched  Just exclude name substring      you know what to do                            if   exe  equals name substring name lastIndexOf       name length                                                              obj addFile temp name name                               System out println temp name                                                      catch StringIndexOutOfBoundsException e                                                          debug purpose                             System out println  ERROR        temp name                                                                               temp obj pop                      obj display               for int i 0 i lt directory length i              System out println directory i               public GetList             this stack   new ArrayList lt  gt             this lnkFile new ArrayList lt  gt             this progName new ArrayList lt  gt               public void push String dir                index              System out println  PUSH     dir     index           this stack add index dir              public String pop                 String dir             if index  -1              return   amp               else                       dir this stack get index                 System out println  POP     dir     index               index--                     return dir             public void addFile String name String name2                lnkFile add name           progName add name2              public void display                 GetList lnkFile stream   forEach  lnkFile1  - gt                System out println lnkFile1

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public class searchingFile         static String path   defining not initializing  these variables outside main       static String filename   so that recursive function can access them      static int counter 0   adding static so that can be accessed by static methods       public static void main String   args    main methods begins               Scanner sc new Scanner System in           System out println  Enter the path               path sc nextLine      storing path in path variable         System out println  Enter file name               filename sc nextLine      storing filename in filename variable         searchfile path    calling our recursive function and passing path as argument         System out println  Number of locations file found at     counter    Printing occurences             public static String searchfile String path   declaring recursive function having return                                                    type and argument both strings                File file new File path    denoting the path         File   filelist file listFiles     storing all the files and directories in array      for  int i   0  i  lt  filelist length  i      for loop for accessing all resources               if filelist i  getName   equals filename    if loop is true if resource name filename                       System out println  File is present at     filelist i  getAbsolutePath                   if loop is true this will print it s location             counter     counter increments if file found                   if filelist i  isDirectory      if resource is a directory we want to inside that folder                       path filelist i  getAbsolutePath     this is the path of the subfolder             searchfile path    this path is again passed into the searchfile function                                 and this countinues untill we reach a file which has                                no sub directories                      return path    returning path variable as it is the return type and also                     because function needs path as argument

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Using Java 8  features we can write the code in few lines   protected static Collection lt Path gt  find String fileName  String searchDirectory  throws IOException       try  Stream lt Path gt  files   Files walk Paths get searchDirectory              return files                  filter f - gt  f getFileName   toString   equals fileName                    collect Collectors toList                Files walk returns a Stream lt Path gt  which is  walking the file tree rooted at  the given searchDirectory  To select the desired files only a filter is applied on the Stream files  It compares the file name of a Path with the given fileName   Note that the documentation of Files walk requires     This method must be used within a try-with-resources statement or   similar control structure to ensure that the stream s open directories   are closed promptly after the stream s operations have completed    I m using the try-resource-statement     For advanced searches an alternative is to use a PathMatcher   protected static Collection lt Path gt  find String searchDirectory  PathMatcher matcher  throws IOException       try  Stream lt Path gt  files   Files walk Paths get searchDirectory              return files                  filter matcher  matches                   collect Collectors toList                An example how to use it to find a certain file   public static void main String   args  throws IOException       String searchDirectory   args 0       String fileName   args 1       PathMatcher matcher   FileSystems getDefault   getPathMatcher  regex       fileName       Collection lt Path gt  find   find searchDirectory  matcher       System out println find       More about it  Oracle Finding Files tutorial

[java] Java - Search for files in a directory

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