public static String toShortString(Throwable e, int stackLevel) {
        StackTraceElement[] traces = e.getStackTrace();
        StringBuilder sb = new StringBuilder(1024);
        sb.append(e.toString()).append("\t");
        if (traces != null) {
            for (int i = 0; i < traces.length; i++) {
                if (i < stackLevel) {
                    sb.append("\tat ").append(traces[i]).append("\t");
                } else {
                    break;
                }
            }
        }
        return sb.toString();
    }
@Test
    public void toShortString() throws Exception {
        SofaRpcException exception = new SofaRpcException(RpcErrorType.SERVER_BUSY, "111");
        String string = ExceptionUtils.toShortString(exception, 1);
        Assert.assertNotNull(string);
        Pattern pattern = Pattern.compile("at");
        Matcher matcher = pattern.matcher(string);
        int count = 0;
        while (matcher.find()) {
            count++;
        }
        Assert.assertTrue(count == 1);
    }