java - HttpURLConnection 应用程序因 ESP8266 而崩溃

Question

我有一个带有以下 Lua 脚本的 ESP8266 简单 http 服务器

print("My First Lua program")
--print(adc.readvdd33())
print("Setting Wifi")
wifi.setmode(wifi.STATIONAP)            --[[ STATION + AP --]]
wifi.setphymode(wifi.PHYMODE_N)         --[[ IEEE 802.n --]]
print(wifi.getmode())
print(wifi.getphymode())
wifi.sta.config("srs", "cometomyn/w0")
tmr.delay(5000000)
print("Delay out")
--print(wifi.sta.getip())
srv=net.createServer(net.TCP) 
srv:listen(80,function(conn) 
    conn:on("receive",function(conn,payload) 
        print(payload) 
        conn:send("<h1> ESP8266<BR>Server is working!</h1>")
        conn:close()
        end) 
end)

当我使用 chrome 通过我的笔记本电脑连接到服务器时，我得到“服务器正在运行!”响应。

但是当我通过我制作的 android 应用程序连接时，它崩溃了:(。以下是我的应用程序代码

public class HttpManager {
public static String downloadUrl(String uri) throws IOException {
    HttpURLConnection con = null;
    InputStream is=null;
    try {
        URL url = new URL(uri);
        con = (HttpURLConnection) url.openConnection();
        con.setReadTimeout(10000);
        con.setConnectTimeout(15000);
        con.setRequestMethod("GET");
        //add request header
        //con.setRequestProperty("User-Agent", "Mozilla/5.0");
        //con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
        is = con.getInputStream();
    }catch (IOException e) {
        e.printStackTrace();
    }
    BufferedReader rd = new BufferedReader(new InputStreamReader(is));
    String line;
    StringBuilder sb =  new StringBuilder();
    while ((line = rd.readLine()) != null) {
        sb.append(line);
    }
    rd.close();
    String contentOfMyInputStream = sb.toString();
    return contentOfMyInputStream;
}

我在异步任务中调用这个 HttpManager。有了这个应用程序，我能够从像谷歌这样的网站得到回应! .

我不确定哪个代码有问题!!! 谁能帮我解决这个问题？

也追加崩溃日志

07-18 11:51:04.122    3710-3710/srs.thebewboston I/First success﹕ http
07-18 11:51:04.312    3710-3985/srs.thebewboston W/System.err﹕ java.io.EOFException
07-18 11:51:04.322    3710-3985/srs.thebewboston W/System.err﹕ at libcore.io.Streams.readAsciiLine(Streams.java:203)
07-18 11:51:04.322    3710-3985/srs.thebewboston W/System.err﹕ at libcore.net.http.HttpEngine.readResponseHeaders(HttpEngine.java:544)
07-18 11:51:04.332    3710-3985/srs.thebewboston W/System.err﹕ at libcore.net.http.HttpEngine.readResponse(HttpEngine.java:784)
07-18 11:51:04.332    3710-3985/srs.thebewboston W/System.err﹕ at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:274)
07-18 11:51:04.342    3710-3985/srs.thebewboston W/System.err﹕ at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:168)
07-18 11:51:04.342    3710-3985/srs.thebewboston W/System.err﹕ at srs.thebewboston.HttpManager.downloadUrl(HttpManager.java:38)
07-18 11:51:04.342    3710-3985/srs.thebewboston W/System.err﹕ at srs.thebewboston.MainActivity$MyATask.doInBackground(MainActivity.java:278)
07-18 11:51:04.342    3710-3985/srs.thebewboston W/System.err﹕ at srs.thebewboston.MainActivity$MyATask.doInBackground(MainActivity.java:264)
07-18 11:51:04.382    3710-3985/srs.thebewboston W/System.err﹕ at android.os.AsyncTask$2.call(AsyncTask.java:264)
07-18 11:51:04.382    3710-3985/srs.thebewboston W/System.err﹕ at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
07-18 11:51:04.412    3710-3985/srs.thebewboston W/System.err﹕ at java.util.concurrent.FutureTask.run(FutureTask.java:137)
07-18 11:51:04.452    3710-3985/srs.thebewboston W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
07-18 11:51:04.472    3710-3985/srs.thebewboston W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
07-18 11:51:04.592    3710-3985/srs.thebewboston W/System.err﹕ at java.lang.Thread.run(Thread.java:856)
07-18 11:51:04.612    3710-3985/srs.thebewboston W/dalvikvm﹕ threadid=12: thread exiting with uncaught exception (group=0x409c01f8)
07-18 11:51:04.652    3710-3985/srs.thebewboston E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
    java.lang.RuntimeException: An error occured while executing doInBackground()
            at android.os.AsyncTask$3.done(AsyncTask.java:278)
            at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
            at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
            at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
            at java.util.concurrent.FutureTask.run(FutureTask.java:137)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
            at java.lang.Thread.run(Thread.java:856)
     Caused by: java.lang.NullPointerException
            at java.io.Reader.<init>(Reader.java:64)
            at java.io.InputStreamReader.<init>(InputStreamReader.java:122)
            at java.io.InputStreamReader.<init>(InputStreamReader.java:59)
            at srs.thebewboston.HttpManager.downloadUrl(HttpManager.java:43)
            at srs.thebewboston.MainActivity$MyATask.doInBackground(MainActivity.java:278)
            at srs.thebewboston.MainActivity$MyATask.doInBackground(MainActivity.java:264)
            at android.os.AsyncTask$2.call(AsyncTask.java:264)
            at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
            at java.util.concurrent.FutureTask.run(FutureTask.java:137)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
            at java.lang.Thread.run(Thread.java:856)

同时添加我的服务器响应

GET  Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.132 Safari/537.36
GET  Dalvik/1.6.0 (Linux; U; Android 4.4.4; MI 3W MIUI/V6.5.3.0.KXDMICD)
GET  Mozilla/5.0 (Linux; Android 4.4.4; MI 3W Build/KTU84P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.93 Mobile Safari/537.36

当我尝试使用笔记本电脑上的 chrome 时的第一个响应(有效)

当我尝试从移动设备上使用我的应用程序时的第二个响应(不工作!!)

当我尝试使用来自同一手机的 chrome 时的第三次响应(有效)

我的Assynctask调用部分

private class MyATask extends AsyncTask<String, String, String>{
        TextView testout = (TextView) findViewById(R.id.testout);
        @Override
        protected void onPreExecute(){
            testout.append("Starting Task" + '\n');
        }
        @Override
        protected String doInBackground(String... params) {
            String httout = null;
            try {
                httout = HttpManager.downloadUrl(params[0]);
            } catch (IOException e) {
                e.printStackTrace();}
            return httout;}
        @Override
        protected void onProgressUpdate(String... values) {
            //testout.append(values[0]+'\n');}
        @Override
        protected void onPostExecute(String result) {
            testout.append(result + '\n');}
    }

Atask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,"http://192.168.1.3");//这个没用 Atask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,"http://www.google.com");//这个有效

谢谢

Answer 1

这段代码基本上存在三个问题:

srv:listen(80,function(conn) 
    conn:on("receive",function(conn,payload) 
        print(payload) 
        conn:send("<h1> ESP8266<BR>Server is working!</h1>")
        conn:close()
        end)

1. conn:send() 是异步的，见API docs .这意味着您不能在调用 conn:send() 后立即关闭连接，因为在您关闭连接时数据可能尚未发送。
2. 您在两个回调函数中重用了 conn 变量。因此，将 function(conn,payload) 更改为 function(whatever,payload)，然后相应地执行 whatever:send。
3. 您发回的不是有效的 HTTP 响应，而只是一些与协议(protocol)无关的 HTML fragment 。

看https://github.com/nodemcu/nodemcu-firmware/blob/dev/README.md#programming-model一个完整的工作示例。