微信公众号搜"智元新知"关注
微信扫一扫可直接关注哦!

java – 为什么android HttpURLConnection没有发回FIN?

从我的 Android应用程序中,我想将数据发布到服务器并获取响应,处理它然后发回并获得另一个请求.由于它是持续通信直到没有更多响应进程,我更喜欢使用http.keepAlive = true的HttpURLConnection.

我尝试重用套接字是成功的,但我遇到的问题是:

>我试图从客户端(Android应用程序)启动关闭,因为如果
终止从服务器开始,然后服务器进入
TIME_WAIT状态.我不希望我的服务器进入该状态,所以我更喜欢我的客户端启动终止.但不幸的是
我发现没有合适的方法来使用HttpURLConnection
>经过几个小时的搜索,我放弃了做上述尝试
从基于服务器的启动关闭开始
keepalivetimeout,但是当服务器发送FIN时,客户端仅使用ACK响应,因为该连接保持打开状态
服务器中的FIN_WAIT_2和代理中的CLOSE_WAIT.

代码

private HttpStatus communicateWithMDMServer(String httpUrl,String dataToSend,boolean keepAlive) {
    HttpStatus status = new HttpStatus(HTTP_STATUS_FAILURE);

    try {

        initializeConnection(httpUrl,keepAlive);
        postDataToConnection(connection,dataToSend);
        status = readDataFromConnection(connection);

    } catch (MalformedURLException e) {
        MDMLogger.error("Failed to send data to server as the URL provided is not valid "+ e.getMessage()+"\n");
        e.printstacktrace();
    } catch (IOException e) {
        MDMLogger.error("Failed to send the status to the server : IOException "+ e.getMessage()+"\n"+e.getStackTrace());
        e.printstacktrace();
        readErrorStreamAndPrint(connection);
    }
    connection.disconnect();
    return status;
}

/**
 * API to close connection,calling this will not force the connection to shutdown
 * this will work based on the Connection header set.
 * @param connection
 */
public void closeConnection(){
    if(connection != null){
        connection.disconnect();
    }
}


/**
 * Used to initialize the HttpURLConnection for the given url
 * All properties required for connection are preset here 
 * Connection Time Out : 20 Seconds
 * Connection Type     : keep alive
 * Content Type        : application/json;charset=UTF-8
 * And also All certificates will be evaluated as Valid.[ Todo will be removed soon]
 * @param httpUrl
 * @return
 * @throws MalformedURLException
 * @throws IOException
 */
private void initializeConnection(String httpUrl,boolean keepAlive) throws MalformedURLException,IOException{

    URL url = new URL(httpUrl);
    connection = (HttpsURLConnection) url.openConnection();

    connection.setConnectTimeout(20000);
    connection.setReadTimeout(20000);
    connection.setDoInput(true);
    connection.setDoOutput(true);
    connection.setRequestMethod("POST");                                                                        //NO I18N
    connection.setRequestProperty("Content-Type","application/json;charset=UTF-8");                            //NO I18N
    connection.setRequestProperty("Connection","Keep-Alive");      //NO I18N
}


/**
 * API to post data to given connection 
 * call to this API will close the @OutputStream
 * @param connection
 * @param data
 * @throws IOException
 */
private void postDataToConnection(URLConnection connection,String data) throws IOException{

    OutputStream outStream = connection.getoutputStream();
    BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outStream));
    writer.write(data);
    writer.flush();
    writer.close();
    outStream.close();
}

/**
 * API to read error stream and log
 * @param connection
 */
private void readErrorStreamAndPrint(URLConnection connection){
    try{
        InputStream inStream = ((HttpURLConnection) connection).getErrorStream();
        String responseData = "";
        String line;
        BufferedReader br=new BufferedReader(new InputStreamReader(inStream));
        while ((line=br.readLine()) != null) {
            responseData+=line;
        }
        MDMLogger.error("ErrorStream Says "+responseData);
    } catch (IOException ioe) {
        MDMLogger.debug("Exception on reading ErrorStream");
    }
}


/**
 * API to read data from given connection and return {@code com.manageengine.mdm.framework.communication.HttpStatus}
 * call to this API will close the @InputStream
 * @param connection
 * @return
 * @throws IOException
 */
private HttpStatus readDataFromConnection(URLConnection connection) throws IOException{

    HttpStatus status = new HttpStatus(HTTP_STATUS_FAILURE);
    int responseCode=((HttpURLConnection) connection).getResponseCode();
    MDMLogger.info("Response Code: "+responseCode);
    InputStream inStream = connection.getInputStream();
    MDMLogger.info("Response Header: "+connection.getHeaderFields());
    String responseData = "";
    if (responseCode == HttpURLConnection.HTTP_OK) {
        responseData = readStreamAsstring(inStream);
        status.setStatus(HTTP_STATUS_SUCCESS);
        status.setUrlDataBuffer(responseData);
        MDMLogger.info("communicateWithMDMServer : Response is \n"  + status.getUrlDataBuffer());
        MDMLogger.info("Successfully send the data to server and received success response ");
    }
    else {
        status.setStatus(HTTP_STATUS_FAILURE);
        MDMLogger.error("Data sent successfully but Failed to get the response and the response code is : " + responseCode);
    }
    inStream.close();
    return status;
}

/**
 * Read the InputStream to String until EOF
 * Call to this API will not close @InputStream
 * @param inStream
 * @return
 * @throws IOException
 */
private String readStreamAsstring(InputStream inStream) throws IOException{
    StringBuilder responseData = new StringBuilder();
    String line;
    BufferedReader br=new BufferedReader(new InputStreamReader(inStream));
    while ((line=br.readLine()) != null) {
        responseData.append(line);
    }
    return responseData.toString();
}

有人可以帮忙吗?

解决方法

当您使用http.keepAlive = true时,连接开始在连接池中循环使用,并保持打开状态.即使服务器关闭了它仍在监听的连接,客户端仍然认为它可以发送数据.毕竟,服务器的FIN只表示服务器不会发送更多数据.

由于连接池的内部逻辑无法访问,因此您几乎无法控制.然而,当您使用https时,您有一个打开较低层的窗口,可以通过HttpsURLConnection.setSSLSocketFactory(SSLSocketFactory)访问创建的Socket.

您可以为认工厂(SSLSocketFactory.getDefault())创建一个允许关闭Socket的包装器.下面的简化:

public class MySSLSocketFactory extends SSLSocketFactory {

    private SSLSocketFactory factory = (SSLSocketFactory) SSLSocketFactory.getDefault();
    private Socket last;

    public void closeLastSocket() {
        if (last != null) {
            last.close();
        }
    }

    public Socket createSocket() throws IOException {
        return this.last = factory.createSocket();
    }

    ...

}

当您关闭底层套接字时,该连接不应该有资格进行回收,并将被丢弃.因此,如果您执行closeLastSocket并断开连接,则连接甚至不应该转到池中,如果您执行其他方式,则只有在创建新连接时才会丢弃连接.

原文地址:https://www.jb51.cc/android/128870.html

版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。

相关推荐