docs: private void internalCopyDirContent(File src, File dest) throws IORuntimeException {
  		if (null != copyFilter && false == copyFilter.accept(src)) {
  			//被过滤的目录跳过
  			return;
  		}
  		
  		if (false == dest.exists()) {
  			//目标为不存在路径，创建为目录
  			dest.mkdirs();
  		} else if (false == dest.isDirectory()) {
  			throw new IORuntimeException(StrUtil.format("Src [{}] is a directory but dest [{}] is a file!", src.getPath(), dest.getPath()));
  		}
  		
  		final String files[] = src.list();
  		File srcFile;
  		File destFile;
  		for (String file : files) {
  			srcFile = new File(src, file);
  			destFile = this.isOnlyCopyFile ? dest : new File(dest, file);
  			// 递归复制
  			if (srcFile.isDirectory()) {
  				internalCopyDirContent(srcFile, destFile);
  			} else {
  				internalCopyFile(srcFile, destFile);
  			}
  		}
  	}