public static String readLines(File logFile){
		BufferedReader reader = null;
		try {
			reader = new BufferedReader(new InputStreamReader(new FileInputStream(logFile), "utf-8"));
			if (reader != null) {
				StringBuilder sb = new StringBuilder();
				String line = null;
				while ((line = reader.readLine()) != null) {
					sb.append(line).append("\n");
				}
				return sb.toString();
			}
		} catch (IOException e) {
			logger.error(e.getMessage(), e);
		} finally {
			if (reader != null) {
				try {
					reader.close();
				} catch (IOException e) {
					logger.error(e.getMessage(), e);
				}
			}
		}
		return null;
	}
read log data
@param logFile
@return log line content
larkmidtable-web/larkmt-core/src/main/java/com/larkmt/core/log/JobFileAppender.java