android - HttpURLConnection setConnectTimeout 不工作

Question

我在我的应用程序中使用 HttpURLConnection 与我的服务器通信。但我发现如果我的 Android 设备连接不良，我的应用程序将挂起很长时间，这是一种糟糕的用户体验。我同时使用 setConnectTimeout() 和 setReadTimeout() 但它似乎不起作用。下面是我的代码:

        URL url = null;
        HttpURLConnection connection = null;
        InputStreamReader ins = null;   
        try {
            url = new URL("XXXXXXXXXXXXXXXXX");
            connection = (HttpURLConnection) url.openConnection();
            connection.setConnectTimeout(10000);
            connection.setReadTimeout(10000);
            ins = new InputStreamReader(connection.getInputStream());  
            BufferedReader bufferedReader = new BufferedReader(ins);
            StringBuffer strBuffer = new StringBuffer();
            String line = null;
            while ((line = bufferedReader.readLine()) != null) {
                strBuffer.append(line);
            }       
            result = strBuffer.toString();       
            line = null;
            strBuffer = null;
            bufferedReader = null;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.disconnect();
                connection = null;
            }
            if (ins != null) {
                try {
                    ins.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                ins = null;
            }
            url = null;
        }

从我的代码中我们可以看到，当我的互联网连接状况不佳时，我同时使用了 setConnectTimeout() 和 setReadTimeout()。但是，它仍然挂了很长时间(超过30秒甚至更多)，最后会显示这样的日志:

    07-17 13:27:47.200: W/System.err(18005): java.net.UnknownHostException: Unable to resolve host "server.ibaobeimao.com": No address associated with hostname
    07-17 13:27:47.200: W/System.err(18005):    at java.net.InetAddress.lookupHostByName(InetAddress.java:424)
    07-17 13:27:47.200: W/System.err(18005):    at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
    07-17 13:27:47.200: W/System.err(18005):    at java.net.InetAddress.getAllByName(InetAddress.java:214)
    07-17 13:27:47.200: W/System.err(18005):    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70)
    07-17 13:27:47.203: W/System.err(18005):    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
    07-17 13:27:47.207: W/System.err(18005):    at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
    07-17 13:27:47.207: W/System.err(18005):    at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
    07-17 13:27:47.207: W/System.err(18005):    at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
    07-17 13:27:47.207: W/System.err(18005):    at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316)
    07-17 13:27:47.207: W/System.err(18005):    at libcore.net.http.HttpEngine.connect(HttpEngine.java:311)
    07-17 13:27:47.210: W/System.err(18005):    at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290)
    07-17 13:27:47.210: W/System.err(18005):    at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240)
    07-17 13:27:47.210: W/System.err(18005):    at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:282)
    07-17 13:27:47.213: W/System.err(18005):    at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:177)
    07-17 13:27:47.213: W/System.err(18005):    at utils.Rpc.httpRequest(Rpc.java:49)
    07-17 13:27:47.213: W/System.err(18005):    at utils.Utils$11.run(Utils.java:1154)
    07-17 13:27:47.213: W/System.err(18005):    at java.lang.Thread.run(Thread.java:856)
    07-17 13:27:47.213: W/System.err(18005): Caused by: libcore.io.GaiException: getaddrinfo failed: EAI_NODATA (No address associated with hostname)
    07-17 13:27:47.217: W/System.err(18005):    at libcore.io.Posix.getaddrinfo(Native Method)
    07-17 13:27:47.217: W/System.err(18005):    at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:60)
    07-17 13:27:47.217: W/System.err(18005):    at java.net.InetAddress.lookupHostByName(InetAddress.java:405)
    07-17 13:27:47.217: W/System.err(18005):    ... 16 more
    07-17 13:27:47.217: W/System.err(18005): Caused by: libcore.io.ErrnoException: getaddrinfo failed: ETIMEDOUT (Connection timed out)
    07-17 13:27:47.220: W/System.err(18005):    ... 19 more

那么，我该怎么做才能为我的 HttpURLConnection 超时设置一个时间长度？为什么 setConnectTimeout() 和 setReadTimeout() 不起作用？

这是我在 android 中使用 ping 的尝试，但由于某些未知原因，它仍然不起作用，但我将列出我使用的方法:

public static final boolean ping() {

    String result = null;
    try {
        String ip = "202.108.22.5"; // ping address
        Process p = Runtime.getRuntime().exec("/system/bin/ping -c 1 -w 10 " + ip); // ping 3 times

        InputStream input = p.getInputStream();
        BufferedReader in = new BufferedReader(new InputStreamReader(input));
        StringBuffer stringBuffer = new StringBuffer();
        String content = "";
        while ((content = in.readLine()) != null) {
            stringBuffer.append(content);
        }

        // ping's situation
        int status = p.waitFor();
        if (status == 0) {
            result = "success";
            return true;
        } else {
            result = "failed";
        }
    } catch (IOException e) {
        result = "IOException";
    } catch (InterruptedException e) {
        result = "InterruptedException";
    } finally {
        Log.d("----result---", "result = " + result);
    }
    return false;
}

但是无论我是否真的连接到互联网，我的结果总是错误的。谁能给我更多建议？

Answer 1

不幸的是，您的问题出在较低的网络层。您的参数仅在请求 HTTP 时起作用。你被困在解析 DNS 上。事件顺序:

• 解析dns
• 建立TCP连接
• 发送HTTP请求
• 接收 HTTP 响应

我唯一能想到的处理方法是进行连接检查，例如打开与 google gen_204 的连接。