public static String readFile(String path) throws IOException {

		ClassPathResource classPathResource = new ClassPathResource(path);

		if (classPathResource.exists() && classPathResource.isReadable()) {
			try (InputStream inputStream = classPathResource.getInputStream()) {
				return StreamUtils.copyToString(inputStream, StandardCharsets.UTF_8);
			}
		}
		return "";
	}
@Test
	public void testReadExistedFile() throws IOException {
		String content = ResourceFileUtils.readFile("test.txt");
		assertThat(content).isEqualTo("just for test");
	}