code: public static void copyResourceToFile(String resourceAbsoluteClassPath, File targetFile) throws IOException {
          InputStream is = ResourceUtil.class.getResourceAsStream(resourceAbsoluteClassPath);
          if (is == null) {
              throw new IOException("Resource not found! " + resourceAbsoluteClassPath);
          }
          OutputStream os = null;
          try {
              os = new FileOutputStream(targetFile);
              byte[] buffer = new byte[2048];
              int length;
              while ((length = is.read(buffer)) != -1) {
                  os.write(buffer, 0, length);
              }
              os.flush();
          } finally {
              try {
                  is.close();
                  if (os != null) {
                      os.close();
                  }
              } catch (Exception ignore) {
                  // ignore
              }
          }
      }
docs: Copy resources to file system.
  
  @param resourceAbsoluteClassPath resource's absolute class path, start with "/"
  @param targetFile                target file
  @throws java.io.IOException