Question

当我调用REST API时，我得到EOFException。我知道它说响应是空的。但它不应该。我在iOS应用程序中使用相同的API没有任何问题。

这是我的代码：

try {
    url = new URL(baseUrl);
}
    // Thrown when URL could not be parsed
    catch (MalformedURLException me) {
        Log.e(TAG, "URL could not be parsed. URL : " + baseUrl, me);
    }
    try {

    //      System.setProperty("http.keepAlive", "false");

    // Set connection properties
    urlConnection = (HttpURLConnection) url.openConnection();
    urlConnection.setRequestMethod(method);
    urlConnection.setConnectTimeout(TIMEOUT * 1000);
    urlConnection.setChunkedStreamingMode(0);
    urlConnection.setRequestProperty("Accept", "*/*");
    urlConnection.setRequestProperty("Content-type", "application/x-www-form-urlencoded");

    //      urlConnection.setRequestProperty("Connection", "close");

    if (method.equals("POST") || method.equals("PUT")) {
        // Set to true when posting data
        urlConnection.setDoOutput(true);

        // Write data to post to connection output stream
        OutputStream out = urlConnection.getOutputStream();
        out.write(postParameters.getBytes("UTF-8"));
        Log.d(TAG, "Data written to output stream.");
    }

    //      urlConnection.connect();

    try {
        // Get response
        in = new BufferedInputStream(urlConnection.getInputStream());
    } catch (IOException e) {
            Log.e(TAG,
                    "Exception in getting connection input stream. Input stream : "
                                + in, e);
    }

    Log.d(TAG, "content length : " + urlConnection.getContentLength());
    Log.d(TAG, "content type : " + urlConnection.getContentType());

    // Read the input stream that has response
    statusCode = urlConnection.getResponseCode();
    Log.d(TAG, "Status code : " + statusCode);

    if (statusCode >= 400) {
        Log.e(TAG, "Error stream : " + urlConnection.getErrorStream().toString());
    }
    // Passing input stream to a function.          
    readStream(in, statusCode);
} catch (ProtocolException pe) {
    Log.e(TAG,
                    "Make sure HTTP method is set before connecting to URL. Line : "
                            + getLineNumber(), pe);
} catch (IllegalStateException ie) {
    Log.e(TAG,
                    "Set connection properties before connecting to URL. Line : "
                            + getLineNumber(), ie);
}
// Thrown when connecting to URL times out
catch (SocketTimeoutException se) {
    Log.e(TAG, "Timeout before connecting to URL : " + baseUrl
                    + ". Line : " + getLineNumber(), se);


} catch (IOException e) {
    Log.e(TAG, "Exception while connecting to URL : " + baseUrl, e);
} finally {
    urlConnection.disconnect();
}

我尝试了以下内容，但没有奏效。这些论文在代码中被注释掉了。：

1）System.setProperty("http.keepAlive", "false");
2）urlConnection.setRequestProperty("Connection", "close");
3）urlConnection.connect();

语句Log.d(TAG, "Status code : " + statusCode);未被记录。通常它有效。

Logcat屏幕截图：

enter image description here

Answer 1

显然这是由于HTTPUrlConnection中的错误（请参阅this answer on StackOverflow）。我建议你实现一个重试机制。这就是我实施的例子：

/** POST an object on the server using the REST API. */
private int httpPOST(String path, JSONObject json) {
    final static int MAX_RETRIES = 3;
    int numTries = 0;
    int responseCode = 0;
    HttpsURLConnection urlConnection = null;
    final long startTime = System.currentTimeMillis();

    while (numTries < MAX_RETRIES) {

        if (numTries != 0) {
            LOGV(TAG, "Retry n°" + numTries);
        }

        // Create (POST) object on server
        try {
            byte[] bytes = json.toString().getBytes("UTF-8");
            URL url = new URL(path);
            urlConnection = (HttpsURLConnection) url.openConnection();
            urlConnection.setDoOutput(true);
            urlConnection.setFixedLengthStreamingMode(bytes.length);
            urlConnection.setRequestProperty("Content-Type", "application/json;charset=utf-8");
            LOGV(TAG, "HTTP POST " + url.toString());
            OutputStream out = urlConnection.getOutputStream();
            out.write(bytes);
            out.close();
            responseCode = urlConnection.getResponseCode();
            LOGV(TAG, "HTTP POST response code: " + responseCode + " (" + (System.currentTimeMillis() - startTime)
                    + "ms)");
            return responseCode;

        } catch (UnsupportedEncodingException e) {
            LOGV(TAG, "Unsupported encoding exception");
        } catch (MalformedURLException e) {
            LOGV(TAG, "Malformed URL exception");
        } catch (IOException e) {
            LOGV(TAG, "IO exception: " + e.toString());
            // e.printStackTrace();
        } finally {

            if (urlConnection != null)
                urlConnection.disconnect();
        }

        numTries++;
    }

    LOGV(TAG, "Max retries reached. Giving up...");

    return responseCode;

}

Answer 2

以下代码可以帮助您

HttpEntity entity = response.getEntity();

// All the work is done for you here :)
String jsonContent = EntityUtils.toString(entity);

// Create a Reader from String
Reader stringReader = new StringReader(jsonContent);

// Pass the string reader to JsonReader constructor
JsonReader reader = new JsonReader(stringReader);
reader.setLenient(true);
readGson(reader);

...
// at the end of method return the JSON response
return jsonContent;

Answer 3

EOFException表明响应格式错误 - 标题后可能缺少空行。在这种情况下，一些HTTP客户端代码更宽容，对我来说iOS可以很好地处理我的服务器响应，但我在Android上使用HttpURLConnection获得了EOFException。

我的服务器正在使用python SimpleHTTPServer，我错误地假设我需要做的就是表明成功如下：

self.send_response(200)

它发送初始响应标题行，服务器和日期标题，但使流处于您能够发送其他标题的状态。 HTTP需要在标题之后添加一个新行以表示它们已完成。当你尝试使用HttpURLConnection获取结果体InputStream或响应代码等时，如果这个新行不存在，那么它会抛出EOFException（这实际上是合理的，考虑它）。一些HTTP客户端确实接受了短响应并报告了成功结果代码，这导致我可能不公平地指责HttpURLConnection。

我改变了我的服务器来改为：

self.send_response(200)
self.send_header("Content-Length", "0")
self.end_headers()

该代码不再有EOFException。

注意：Android之前的Froyo（2.2）存在一些与保持连接有关的错误 - 请参阅此处的博文：http://android-developers.blogspot.co.uk/2011/09/androids-http-clients.html。我还没有看到令人信服的证据证明Android的新版本存在漏洞，尽管很多StackOverflow的答案都提到了它（因此我在多个地方提出这个问题......）

Answer 4

尝试使用库https://github.com/kodart/Httpzoid

进行相同的操作

使用HttpUrlConnection获取java.io.EOFException

4 个答案: