How to use PrintWriter and File classes in Java

Question

I am trying to understand PrintWriter for a small program I m making  and I cant seem to get java to make the file and then write on it  When I execute the program below it gives me a Filenotfoundexeption error on line 9  It also fails to make the file in the directory that I specified  I am new to this so please try and keep the answers simple  I am using Eclipse   import java io PrintWriter  import java io File   public class Testing      public static void main String   args         File file   new File   C  Users Me Desktop directory file txt        PrintWriter printWriter   new PrintWriter   file txt        printWriter println   hello        printWriter close

User · Accepted Answer

If the directory doesn t exist you need to create it  Java won t create it by itself since the File class is just a link to an entity that can also not exist at all   As you stated the error is that the file cannot be created  If you read the documentation of PrintWriter constructor you can see     FileNotFoundException - If the given string does not denote an existing  writable regular file and a new regular file of that name cannot be created  or if some other error occurs while opening or creating the file   You should try creating a path for the folder it contains before   File file   new File  C  Users Me Desktop directory file txt    file getParentFile   mkdirs     PrintWriter printWriter   new PrintWriter file

User · Answer

Well I think firstly keep whole main into try catch or you can use as public static void main String arg    throws IOException   and then also use full path of file in which you are writing as  PrintWriter printWriter   new PrintWriter   C  Users Me Desktop directory file txt      all those directies like users Me Desktop directory should be user made  java wont make directories own its own  it should be as  import java io    public class PrintWriterClass    public static void main String arg    throws IOException      PrintWriter pw   new PrintWriter  C  Users Me Desktop directory file txt        pw println  hiiiiiii        pw close

User · Answer

import java io PrintWriter  import java io File   public class Testing      public static void main String   args  throws IOException        File file   new File   C  Users Me Desktop directory file txt        PrintWriter printWriter   new PrintWriter   file txt        printWriter println   hello        printWriter close                    throw an exception for the file

User · Answer

You should have a clear idea of exceptions in java  In java there are checked exceptions and unchecked exceptions   Checked exceptions are checked  not thrown just checked  by the compiler at Compile time for the smooth execution of the program at run time   NOTE  And in our program if their is a chance that a checked exception will rise  then we should handle that checked exception either by try catch or by throws key word Otherwise we will get a compile time Error   CE Unexpected Exception java io FileNotFoundException must be caught or declared to be thrown   How to resolve  1 Put your code in try catch block   2 use throws keyword as shown by other guys above   Advice Read more about Exceptions  I personally love this topic

User · Answer

The PrintWriter class can actually create the file for you    This example works in JDK 1 7       This will create the file txt in your working directory   PrintWriter printWriter   null   try        printWriter   new PrintWriter  file txt    UTF-8           The second parameter determines the encoding  It can be        any valid encoding  but I used UTF-8 as an example     catch  FileNotFoundException   UnsupportedEncodingException error        error printStackTrace       printWriter println  Write whatever you like in your file txt        Make sure to close the printWriter object otherwise nothing    will be written to your file txt and it will be blank  printWriter close      For a list of valid encodings  see the documentation   Alternatively  you can just pass the file path to the PrintWriter class without declaring the encoding

User · Answer

Pass the File object to the constructor PrintWriter File file    PrintWriter printWriter   new PrintWriter file

User · Answer

import java io     public class test      public static void main Strings   args           PrintWriter pw   new PrintWriter new file  C  Users Me Desktop directory file txt             pw println  hello           pw close

User · Answer

Java doesn t normally accept     to use in defining a file directory  so try this    File file   new File   C   Users  user  workspace  FileTester  myFile txt      If the file doesn t exist do    try         file createNewFile        catch  IOException e     e printStackTrace

User · Answer

Double click the file txt  then save it  command   s  that worked in my case  Also  make sure the file txt is saved in the project folder  If that does not work   PrintWriter pw   new PrintWriter new File  file txt     pw println  hello world       to test if it works

User · Answer

If you want to use PrintWrite then try this code    public class PrintWriter       public static void main String   args  throws IOException            java io PrintWriter pw new java io PrintWriter  file txt            pw println  hello world            pw flush            pw close

User · Answer

import java io File  import java io PrintWriter   public class Testing        public static void main String   args                  File file   new File  C  Users Me Desktop directory file txt             PrintWriter printWriter   null           try                       printWriter   new PrintWriter file               printWriter println  hello                      catch  FileNotFoundException e                        e printStackTrace                      finally                       if   printWriter    null                                  printWriter close

[java] How to use PrintWriter and File classes in Java?

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