HOWTO: load a file from a JAR into a String using JAVA

Overview
In some cases, a SQL creation script may be embedded in a jar. The following will show how to load this file into a usable object (String) for later passing to JDBC.

Technique
The idea is simple. Pass the path to the SQL script following the file structure of the JAR. In this example, "/derbyfun/sql/create.sql" is the file that is being extracted.

To get the contents of the file, the resource is opened as a stream and wrapped as a BufferedReader. The stream is then read, line by line, until end of file. For each line, the text is appended to a StringBuilder. At the end of the method, the StringBuilder is turned back into a string where it can be used in a JDBC call.

public String getResourceFileAsString(String resourcefilename) {
  final String newline = System.getProperty("line.separator");
  String line = null;
  URL url = null;
  BufferedReader b = null;
  StringBuilder sb = new StringBuilder();
  int i = 0;
   
  try {
      //
      // open buffered reader
      //
      b = new BufferedReader(
              new InputStreamReader(
                  Main.class.getResourceAsStream(resourcefilename)
              )
          );
    
      //
      // priming read and the loop through rest of file
      //
      line = b.readLine();
      while(line != null) {
          //
          // add the line to the Stirng Builder ensuring
          // the newline is re-added
          //
          sb.append(line + newline);
           //
          // just some debug
          //
          System.out.println("DEBUG: [" + ++i + "] " + line);
       
          //
          // read the next line
          //
          line = b.readLine();
      } // end-while
    
  } catch(Exception ex) {
      ex.printStackTrace();
  } // end-try-catch
   
  return(sb.toString());
}

When the file is ready to be loaded, the following call can be used. In this example, the output is going to standard out. The file is in a sub package called sql which is part of "derbyfun".

System.out.println(
  getResourceFileAsString("/derbyfun/sql/create.sql")
  );

Final Thoughts
This is pretty straight forward code but may come in handy as a cut/paste for someone who does not remember the syntax... like me.