public static Properties loadProps(String fileName) {

        Properties props = null;

        InputStream is = null;

        try {

            //注意：main/java、main/resources、test/java、test/resources这四个目录都是classpath的根目录

            //，当运行单元测试时，遵循“就近原则”，即优先从test/java、test/resources加载类或读取文件

            is = Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName);

            if (is == null) {

                throw new FileNotFoundException(fileName + " file is not found");

            }

            props = new Properties();

            props.load(is);

        } catch (IOException e) {

            LOGGER.error("load properties file failure", e);

        } finally {

            if (is != null) {

                try {

                    is.close();

                } catch (IOException e) {

                    LOGGER.error("close input stream failure", e);

                }

            }

        }

        return props;

    }