public static String readFileToString(final File file, final Charset encoding)
			throws IOException {
		try (InputStream in = openInputStream(file)) {
			return IOUtils.toString(in, Charsets.toCharset(encoding));
		}
	}
Reads the contents of a file into a String. The file is always closed.
@param file the file to read, must not be {@code null}
@param encoding the encoding to use, {@code null} means platform default
@return the file contents, never {@code null}
@throws IOException in case of an I/O error
spring-cloud-alibaba-starters/spring-cloud-alibaba-commons/src/main/java/com/alibaba/cloud/commons/io/FileUtils.java