获取java.net.SocketTimeoutException:连接在android中超时

Question

我对android开发比较陌生.我正在开发一个Android应用程序,我正在向Web服务器发送请求并解析json对象.我经常java.net.SocketTimeoutException: Connection timed out在与服务器通信时遇到异常.有时它会毫无问题地完美运行.我知道这个问题在很多时候都被提出过.但我仍然没有得到任何满意的解决方案来解决这个问题.我正在下面发布我的logcat和app-server通信代码.

public JSONObject RequestWithHttpUrlConn(String _url, String param){

    HttpURLConnection con = null;
    URL url;
    String response = "";
    Scanner inStream = null;
    PrintWriter out = null;
    try {
        url = new URL(_url);
        con = (HttpURLConnection) url.openConnection();
        con.setDoOutput(true);
        con.setRequestMethod("POST");
        if(param != null){
            con.setFixedLengthStreamingMode(param.getBytes().length);
        }
        con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        out = new PrintWriter(con.getOutputStream());
        if(param != null){
            out.print(param);
        }
        out.flush();
        out.close();
        inStream = new Scanner(con.getInputStream());

        while(inStream.hasNextLine()){
            response+=(inStream.nextLine());
        }
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } finally{
        if(con != null){
            con.disconnect();
        }if(inStream != null){
            inStream.close();
        }if(out != null){
            out.flush();
            out.close();
        }
    }
}

logcat的:

03-25 10:55:32.613: W/System.err(18868): java.net.SocketTimeoutException: Connection 
timed out
03-25 10:55:32.617: W/System.err(18868):at org.apache.harmony.luni.platform.OSNetworkSystem.connect(Native Method)
03-25 10:55:32.617: W/System.err(18868):at dalvik.system.BlockGuard
$WrappedNetworkSystem.connect(BlockGuard.java:357)
03-25 10:55:32.617: W/System.err(18868):at 
org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:204)
03-25 10:55:32.617: W/System.err(18868):at 
org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:437)
03-25 10:55:32.617: W/System.err(18868):at        java.net.Socket.connect(Socket.java:1002)
03-25 10:55:32.621: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnection.<init>
(HttpConnection.java:75)
03-25 10:55:32.621: W/System.err(18868): at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnection.<init>
(HttpConnection.java:48)03-25 10:55:32.624: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnection$Address.connect
(HttpConnection.java:322)03-25 10:55:32.624: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnectionPool.get
(HttpConnectionPool.java:89)03-25 10:55:32.628: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getHttpCon
nection(HttpURLConnectionImpl.java:285)
03-25 10:55:32.628: W/System.err(18868):at     org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.makeConn
ection(HttpURLConnectionImpl.java:267)
03-25 10:55:32.636: W/System.err(18868):at
org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.connect
(HttpURLConnectionImpl.java:205)
03-25 10:55:32.636: W/System.err(18868):at 
org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getOutputS
tream(HttpURLConnectionImpl.java:614)
03-25 10:55:32.636: W/System.err(18868):at 
com.myapp.core.JSONRequest.RequestWithHttpUrlConn(JSONRequest.java:63)
03-25 10:55:32.636: W/System.err(18868):    at com.myapp.core.DetailPage
$AsyncRecBooks.doInBackground(AKBookDetailView.java:265)
03-25 10:55:32.640: W/System.err(18868):    at com.myapp.core.DetailPage
$AsyncRecBooks.doInBackground(AKBookDetailView.java:1)
03-25 10:55:32.640: W/System.err(18868):    at android.os.AsyncTask$2.call
(AsyncTask.java:185)
03-25 10:55:32.640: W/System.err(18868):    at java.util.concurrent.FutureTask
$Sync.innerRun(FutureTask.java:306)
03-25 10:55:32.640: W/System.err(18868):    at java.util.concurrent.FutureTask.run
(FutureTask.java:138)
03-25 10:55:32.640: W/System.err(18868):    at 
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
03-25 10:55:32.648: W/System.err(18868):    at 
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
03-25 10:55:32.648: W/System.err(18868):    at java.lang.Thread.run(Thread.java:1019)
03-25 10:55:32.652: E/JSON Parser(18868): Error parsing data org.json.JSONException:  
End of input at character 0 of 

任何人都可以帮我找到解决方案吗？提前致谢....

Answer 1

我在网上搜索过,在阅读了很多关于连接超时异常的文档后,我理解的是,防止SocketTimeoutException超出了我们的限制...有效处理它的一种方法是定义一个连接超时,然后处理它通过使用try catch块....希望这将有助于未来面临同样问题的任何人.

HttpUrlConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(7000); //set the timeout in milliseconds

Answer 2

我知道这个问题有点老了.但由于我在做研究时偶然发现了这一点,我认为一点点补充可能会有所帮助.

如上所述,客户端无法解决错误,因为它是与网络相关的问题.但是,您可以做的是重试连接几次.这可以作为一种解决方法,直到真正的问题得到解决.

for (int retries = 0; retries < 3; retries++) {
    try {
        final HttpClient client = createHttpClientWithDefaultSocketFactory(null, null);
        final HttpResponse response = client.execute(get);
        final int statusCode = response.getStatusLine().getStatusCode();
        if (statusCode != 200) {
            throw new IllegalStateException("GET Request on '" + get.getURI().toString() + "' resulted in " + statusCode);
        } else {                
            return response.getEntity();
        }
    } catch (final java.net.SocketTimeoutException e) {
        // connection timed out...let's try again                
    }
}

也许这有助于某人.

Answer 3

如果您使用Kotlin + Retrofit + Coroutines，那么只需使用try和catch进行网络操作，例如，

viewModelScope.launch(Dispatchers.IO) {
        try {
            val userListResponseModel = apiEndPointsInterface.usersList()
            returnusersList(userListResponseModel)
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

其中，异常是类型kotlin而不是类型java.lang

这将处理每个异常，例如，

1. HttpException
2. 套接字超时异常
3. 致命异常：DefaultDispatcher 等

这是我的usersList()功能

@GET(AppConstants.APIEndPoints.HOME_CONTENT)
suspend fun usersList(): UserListResponseModel

注意： 您的 RetrofitClient 类必须将其作为client

OkHttpClient.Builder()
            .connectTimeout(10, TimeUnit.SECONDS)
            .readTimeout(10, TimeUnit.SECONDS)
            .writeTimeout(10, TimeUnit.SECONDS)