Read properties file outside JAR file

Question

I have a JAR file where all my code is archived for running  I have to access a properties file which need to be changed edited before each run  I want to keep the properties file in the same directory where the JAR file is  Is there anyway to tell Java to pick up the properties file from that directory    Note  I do not want to keep the properties file in home directory or pass the path of the properties file in command line argument

User · Answer

There s always a  problem accessing files on your file directory from a jar file  Providing the classpath in a jar file is very limited  Instead try using a bat file or a sh file to start your program  In that way you can specify your classpath anyway you like  referencing any folder anywhere on the system   Also check my answer on this question   making  exe file for java project containing sqlite

User · Answer

I have an example of doing both by classpath or from external config with log4j2 properties  package org mmartin app1   import java io File  import java io FileInputStream  import java io IOException  import java io InputStream  import java util Properties   import org apache logging log4j Logger  import org apache logging log4j core LoggerContext  import org apache logging log4j LogManager    public class App1       private static Logger logger null       private static final String LOG PROPERTIES FILE    config log4j2 properties       private static final String  CONFIG PROPERTIES FILE    config config properties        private Properties properties  new Properties         public App1             System out println  --Logger intialized with classpath properties file--            intializeLogger1            testLogging            System out println  --Logger intialized with external file--            intializeLogger2            testLogging                  public void readProperties              InputStream input   null          try               input   new FileInputStream CONFIG PROPERTIES FILE               this properties load input             catch  IOException e                logger error  Unable to read the config properties file   e               System exit 1                        public void printProperties             this properties list System out              public void testLogging             logger debug  This is a debug message            logger info  This is an info message            logger warn  This is a warn message            logger error  This is an error message            logger fatal  This is a fatal message            logger info  Logger s name    logger getName                 private void intializeLogger1             logger   LogManager getLogger App1 class             private void intializeLogger2             LoggerContext context    org apache logging log4j core LoggerContext  LogManager getContext false           File file   new File LOG PROPERTIES FILE              this will force a reconfiguration         context setConfigLocation file toURI             logger   context getLogger App1 class getName                public static void main String   args            App1 app1   new App1            app1 readProperties            app1 printProperties              --Logger intialized with classpath properties file--  DEBUG  2018-08-27 10 35 14 510  main  App1 - This is a debug message  INFO   2018-08-27 10 35 14 513  main  App1 - This is an info message  WARN   2018-08-27 10 35 14 513  main  App1 - This is a warn message  ERROR  2018-08-27 10 35 14 513  main  App1 - This is an error message  FATAL  2018-08-27 10 35 14 513  main  App1 - This is a fatal message  INFO   2018-08-27 10 35 14 514  main  App1 - Logger s name  org mmartin app1 App1 --Logger intialized with external file--  DEBUG  2018-08-27 10 35 14 524  main  App1 - This is a debug message  INFO   2018-08-27 10 35 14 525  main  App1 - This is an info message  WARN   2018-08-27 10 35 14 525  main  App1 - This is a warn message  ERROR  2018-08-27 10 35 14 525  main  App1 - This is an error message  FATAL  2018-08-27 10 35 14 525  main  App1 - This is a fatal message  INFO   2018-08-27 10 35 14 525  main  App1 - Logger s name  org mmartin app1 App1 -- listing properties -- dbpassword password database localhost dbuser user

User · Answer

This works for me  Load your properties file from current directory  Attention  The method Properties load uses ISO-8859-1 encoding  Properties properties   new Properties    properties load new FileReader new File  quot   quot   getCanonicalPath     File separator    quot java properties quot     properties forEach  k  v  - gt                System out println k    quot     quot    v                Make sure  that java properties is at the current directory   You can just write a little startup script that switches into to the right directory in before  like     bin bash scriptdir  quot    cd  quot    dirname  quot   BASH SOURCE 0   quot    quot   amp  amp  pwd   quot   cd  scriptdir java -jar MyExecutable jar cd -  In your project just put the java properties file in your project root  in order to make this code work from your IDE as well

User · Answer

I did it by other way    Properties prop   new Properties        try            File jarPath new File MyClass class getProtectionDomain   getCodeSource   getLocation   getPath             String propertiesPath jarPath getParentFile   getAbsolutePath            System out println   propertiesPath-  propertiesPath           prop load new FileInputStream propertiesPath   importer properties           catch  IOException e1            e1 printStackTrace             Get Jar file path  Get Parent folder of that file  Use that path in InputStreamPath with your properties file name

User · Answer

So  you want to treat your  properties file on the same folder as the main runnable jar as a file rather than as a resource of the main runnable jar  In that case  my own solution is as follows   First thing first  your program file architecture shall be like this  assuming your main program is main jar and its main properties file is main properties       - the root of your program      main jar      main properties   With this architecture  you can modify any property in the main properties file using any text editor before or while your main jar is running  depending on the current state of the program  since it is just a text-based file  For example  your main properties file may contain   app version 1 0 0 0 app name Hello   So  when you run your main program from its root base folder  normally you will run it like this   java -jar   main jar   or  straight away    java -jar main jar   In your main jar  you need to create a few utility methods for every property found in your main properties file  let say the app version property will have getAppVersion   method as follows          Gets the app version property value from    the   main properties file of the base folder        return app version string     throws IOException      import java util Properties   public static String getAppVersion   throws IOException       String versionString   null         to load application s properties  we use this class     Properties mainProperties   new Properties         FileInputStream file         the base folder is     the root of the main properties file       String path      main properties          load the file handle for main properties     file   new FileInputStream path          load all the properties from this file     mainProperties load file          we have loaded the properties  so close the file handle     file close           retrieve the property we are intrested  the app version     versionString   mainProperties getProperty  app version         return versionString      In any part of the main program that needs the app version value  we call its method as follows   String version   null  try       version   getAppVersion      catch  IOException ioe       ioe printStackTrace

User · Answer

Here if you mention  getPath   then that will return the path of Jar and I guess you will need its parent to refer to all other config files placed with the jar  This code works on Windows  Add the code within the main class  File jarDir   new File MyAppName class getProtectionDomain   getCodeSource   getLocation   getPath     String jarDirpath   jarDir getParent     System out println jarDirpath

User · Answer

I have a similar case  wanting my   jar file to access a file in a directory next to said   jar file   Refer to THIS ANSWER as well   My file structure is      - the root of your program       jar     dir-next-to-jar some txt   I m able to load a file  say  some txt  to an InputStream inside the   jar file with the following   InputStream stream   null      try          stream   ThisClassName class getClass   getResourceAsStream   dir-next-to-jar some txt              catch Exception e            System out print  error file to stream              System out println e getMessage             Then do whatever you will with the stream

[java] Read properties file outside JAR file

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