解析格式 - 解析异常

Question

我正在使用 ical4j 解析 Android 上的 ical 格式。

我的输入 ics 是：

    BEGIN:VCALENDAR
    BEGIN:VEVENT
    SEQUENCE:5
    DTSTART;TZID=US/Pacific:20021028T140000
    DTSTAMP:20021028T011706Z
    SUMMARY:Coffee with Jason
    UID:EC9439B1-FF65-11D6-9973-003065F99D04
    DTEND;TZID=US/Pacific:20021028T150000
    END:VEVENT
    END:VCALENDAR

但是当我尝试解析它时，出现异常：

第 1 行错误：预期 [VCALENDAR]，读取 [VCALENDARBEGIN]

相关代码是：

    HttpHelper httpHelper = new HttpHelper(
            "http://10.0.2.2/getcalendar.php", params);
    StringBuilder response = httpHelper.postData();

    StringReader sin = new StringReader(response.toString());
    CalendarBuilder builder = new CalendarBuilder();
    Calendar cal = null;
    try {
        cal = builder.build(sin);
    } catch (IOException e) {
        Log.d("calendar", "io exception" + e.getLocalizedMessage());
    } catch (ParserException e) {
        Log.d("calendar", "parser exception" + e.getLocalizedMessage());

}

public class HttpHelper {
final HttpClient client;
final HttpPost post;
final List<NameValuePair> data;

public HttpHelper(String address, List<NameValuePair> data) {
    client = new DefaultHttpClient();
    post = new HttpPost(address);
    this.data = data;
}

private class GetResponseTask extends AsyncTask<Void, Void, StringBuilder> {
    protected StringBuilder doInBackground(Void... arg0) {
        try {
            HttpResponse response = client.execute(post);
            return inputStreamToString(response.getEntity().getContent());
        } catch (ClientProtocolException e) {
        } catch (IOException e) {
        }
        return null;
    }
}

public StringBuilder postData() {
    try {
        post.setEntity(new UrlEncodedFormEntity(data));
        return (new GetResponseTask().execute()).get();
    } catch (UnsupportedEncodingException e) {
    } catch (InterruptedException e) {
    } catch (ExecutionException e) {
    }
    return null;
}

private StringBuilder inputStreamToString(InputStream is)
        throws IOException {
    String line = "";
    StringBuilder total = new StringBuilder();

    // Wrap a BufferedReader around the InputStream
    BufferedReader rd = new BufferedReader(new InputStreamReader(is));

    // Read response until the end
    while ((line = rd.readLine()) != null) {
        total.append(line);
        Log.v("debug", "Line: " + line);
    }
    // Return full string
    return total;
}
}

Answer 1

我的猜测是响应字符串中的行结尾与 ical4j 期望的不同。

标准指定您应该使用 CRLF（又名“\r\n”）。

Answer 2

输入文件有效，问题出在您的方法 inputStreamToString() 上，该方法对输入执行 readLine() （去除换行符）并附加到字符串而不重新添加换行符。

我建议使用 readLine() 的替代方法（如果您想保留原始文件中的换行符），或者在循环中附加您自己的换行符，例如：

while ((line = rd.readLine()) != null) {
    total.append(line);
    total.append("\r\n");
    Log.v("debug", "Line: " + line);
}