如何从服务器获取回声

Question

我正在尝试从服务器获取回显回复。 这样做的目的是检查Internet连接并检查服务器状态。 如果我得到答复，将出现一个对话框，其中包含一条简单消息。 同样没有得到答复。

当我收到答复时，将出现该对话框，但当我未收到答复时，将不会显示该对话框。

在我的uploadDB.class中，我有多种情况将在PHP文件中执行不同的功能。 一种情况是“ ping”功能，另一种情况是“ updatecounter”功能。

当我在我的uploadDB.class中删除“ updatecounter”案例时，一切似乎都可以正常工作。 根据我的要求，我不希望删除“ updatecounter”案例。

有人可以建议我如何解决这个问题吗？

以下是我在Logcat中的代码和错误。

PHP文件

        if (isset($_POST['type'])){
        if ($_POST['type'] == "ping"){
        echo "success";
        }

MainActivity.class

public boolean isInternetConnected = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        pingTask();
    }

    private void pingTask() {
        new uploadDB(new uploadDB.returnResult() {
            @Override
            public void onFinish(String result) {
                if (result.equalsIgnoreCase("success")) {
                    isInternetConnected = true;
                    showdialog("Server Status", "Working");
                } else {
                    isInternetConnected = false;
                    showdialog("Server Status", "Not Working");
                }
            }
        }).execute("ping");
    }

uploadDB.class

protected String doInBackground(String... params) {
        String method = params[0];
        String data = "";
        String link = "www.example.com/example.php";

        switch (method){
            case "ping": {
                try{
                    data = URLEncoder.encode("type", "UTF-8") + "=" + URLEncoder.encode("ping", "UTF-8");
                    Log.e(TAG,"DATA: " + data);
                }catch (UnsupportedEncodingException e){
                    Log.e(TAG, "UnsupportedEncodingException: " + e.toString());
                }
                try {
                    URL url = new URL(link);
                    HttpURLConnection h = (HttpURLConnection) url.openConnection();
                    h.setDoInput(true);
                    h.setDoOutput(true);
                    OutputStreamWriter owriter =
                            new OutputStreamWriter(h.getOutputStream());
                    owriter.write(data);
                    owriter.flush();
                    BufferedReader b = new BufferedReader
                            (new InputStreamReader(h.getInputStream(), "UTF-8"), 8);
                    StringBuilder builder = new StringBuilder();
                    String line;
                    while ((line = b.readLine()) != null) {
                        builder.append(line);
                    }
                    return builder.toString();
                } catch (IOException e) {
                    Log.e(TAG, "IOException: " + e.toString());
                }
            }

          case "updatecounter": {
                String macAddress = params[1];
                String sensorname = params[2];
                String counter = params[3];
                try {
                    data = URLEncoder.encode("type", "UTF-8") + "=" + URLEncoder.encode("counter", "UTF-8")
                            + "&" + URLEncoder.encode("gate_name", "UTF-8") + "=" + URLEncoder.encode(sensorname, "UTF-8")
                            + "&" + URLEncoder.encode("mac", "UTF-8") + "=" + URLEncoder.encode(macAddress, "UTF-8")
                            + "&" + URLEncoder.encode("counter", "UTF-8") + "=" + URLEncoder.encode(counter, "UTF-8");
                    Log.e(TAG,"DATA: " + data);
                } catch (UnsupportedEncodingException e) {
                    Log.e(TAG, "UnsupportedEncodingException: " + e.toString());
                }

                try {
                    URL url = new URL(link);
                    HttpURLConnection h = (HttpURLConnection) url.openConnection();
                    h.setDoInput(true);
                    h.setDoOutput(true);
                    OutputStreamWriter owriter =
                            new OutputStreamWriter(h.getOutputStream());
                    owriter.write(data);
                    owriter.flush();
                    BufferedReader b = new BufferedReader
                            (new InputStreamReader(h.getInputStream(), "UTF-8"), 8);
                    StringBuilder builder = new StringBuilder();
                    String line;
                    while ((line = b.readLine()) != null) {
                        builder.append(line);
                    }
                    return builder.toString();
                } catch (IOException e) {
                    //activity.isInternetConnected = false;
                    Log.e(TAG, "IOException: " + e.toString());
                }
            }

Logcat错误

Process: com.example.postserver, PID: 21624
    java.lang.RuntimeException: An error occurred while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:353)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:383)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:252)
        at java.util.concurrent.FutureTask.run(FutureTask.java:271)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
        at java.lang.Thread.run(Thread.java:764)
     Caused by: java.lang.ArrayIndexOutOfBoundsException: length=1; index=1
        at com.example.postserver.uploadDB.doInBackground(uploadDB.java:69)
        at com.example.postserver.uploadDB.doInBackground(uploadDB.java:16)

Answer 1

您需要在案例结尾处添加一个休息时间。 如果不添加它，则此后的每种情况都将执行：

   switch (method){
        case "ping": {
            try{
                data = URLEncoder.encode("type", "UTF-8") + "=" + URLEncoder.encode("ping", "UTF-8");
                Log.e(TAG,"DATA: " + data);
            }catch (UnsupportedEncodingException e){
                Log.e(TAG, "UnsupportedEncodingException: " + e.toString());
            }
            try {
                URL url = new URL(link);
                HttpURLConnection h = (HttpURLConnection) url.openConnection();
                h.setDoInput(true);
                h.setDoOutput(true);
                OutputStreamWriter owriter =
                        new OutputStreamWriter(h.getOutputStream());
                owriter.write(data);
                owriter.flush();
                BufferedReader b = new BufferedReader
                        (new InputStreamReader(h.getInputStream(), "UTF-8"), 8);
                StringBuilder builder = new StringBuilder();
                String line;
                while ((line = b.readLine()) != null) {
                    builder.append(line);
                }
                return builder.toString();
            } catch (IOException e) {
                Log.e(TAG, "IOException: " + e.toString());
            }
        }
        break;
    case "updatecounter": {

Answer 2

您可以从android studio中的服务器获取任何响应

InputStream inputStream = httpURLConnection.getInputStream();
                InputStreamReader inputStreamReader = new InputStreamReader(inputStream,"UTF-8");
                BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
                String dataResponse = "";
                String inputLine = "";
                while((inputLine = bufferedReader.readLine()) != null){
                    dataResponse += inputLine;
                }
                bufferedReader.close();
                inputStream.close();
                httpURLConnection.disconnect();

之后，您可以打印出您的回复

System.out.println(dataResponse);

将该代码放在您的邮政编码之后