分行读取string内容

public static void main(String[] args) {
    try {
        String s = "testrntestrntestrn rntestrn";
        InputStreamReader in = new InputStreamReader(new ByteArrayInputStream(s.getBytes(Charset.forName("utf8"))), Charset.forName("utf8"));
        BufferedReader br = new BufferedReader(in);
        String line = null;
        StringBuffer sb = new StringBuffer();
        while ((line = br.readLine()) != null) {
            if (!line.trim().isEmpty()) {
                line = "--" + line;
                sb.append(line + "rn");
            }
        }
        System.out.println(sb.toString());
    } catch (Exception ex) {
        ex.printStackTrace();
    }
}