code: private static File getCodeSourceArchive() {
          try {
              CodeSource codeSource = DocumentRootHelper.class.getProtectionDomain().getCodeSource();
              URL location = (codeSource == null ? null : codeSource.getLocation());
              if (location == null) {
                  return null;
              }
              String path = location.getPath();
              URLConnection connection = location.openConnection();
              if (connection instanceof JarURLConnection) {
                  path = ((JarURLConnection) connection).getJarFile().getName();
              }
              if (path.indexOf("!/") != -1) {
                  path = path.substring(0, path.indexOf("!/"));
              }
              return new File(path);
          } catch (IOException ex) {
              return null;
          }
      }
docs: 获取当前代码的文件
  
  @return 当前代码所处的文件