JavaEE 環境でクラスパス配下のファイルを文字列として読み込む(JSON等)

DebugUtil.java

  // dir name(class pathをルートとする相対パス)
  private static final String DIR_NAME = "json";
  private static final String FILE_NAME = "test.json";

  public static String createJsonText(Class<? extends HttpServlet> clazz) {
      return createJsonText(clazz, DIR_NAME, FILE_NAME);
  }

  public static String createJsonText(Class<? extends HttpServlet> clazz, String dirName, String fileName) {
      String dirPath = clazz.getClassLoader().getResource(dirName).getPath();
      return createJsonText(new File(dirPath, fileName));
  }

  private static String createJsonText(File jsonFile) {
      try {
          byte[] bytes = Files.readAllBytes(Paths.get(jsonFile.toURI()));
          return new String(bytes, StandardCharsets.UTF_8);
      } catch (Exception e) {
          return null;
      }
  }