java - 我如何将我的数据库连接到我的 Android 应用程序

Question

所以我对数据库很陌生，我几天前才学了 mysql，但是我正在尝试连接到 000webhost.com 托管的数据库，我已经创建了 php 文件来连接并从数据库获取数据并将其转换json 但每当我尝试从我的应用程序访问 php 文件时，它都会显示错误。 我的代码:

protected String doInBackground(String[] p1)
        {

            try
            {
                URL url = new URL("https://example.000webhostapp.com/Export.php");

                URLConnection urlconnection = url.openConnection();
                InputStreamReader inputstream = new InputStreamReader(urlconnection.getInputStream());
                BufferedReader reader = new BufferedReader(inputstream);
            }
            catch (MalformedURLException e)
            {e.printStackTrace();}
            catch (IOException e)
            {e.printStackTrace();}

            return null;
        }

错误:

04-04 07:38:25.222 20067 20090 W   System.err                                   java.net.ConnectException: Failed to connect to example.000webhostapp.com/145.14.144.173:443
04-04 07:38:25.225 20067 20090 W   System.err                                   at com.android.okhttp.internal.io.RealConnection.connectSocket(RealConnection.java:1417)
04-04 07:38:25.226 20067 20090 W   System.err                                   at com.android.okhttp.internal.io.RealConnection.connect(RealConnection.java:1367)
04-04 07:38:25.227 20067 20090 W   System.err                                   at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:219)
04-04 07:38:25.227 20067 20090 W   System.err                                   at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:142)
04-04 07:38:25.228 20067 20090 W   System.err                                   at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:104)
04-04 07:38:25.229 20067 20090 W   System.err                                   at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:392)
04-04 07:38:25.230 20067 20090 W   System.err                                   at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:325)
04-04 07:38:25.231 20067 20090 W   System.err                                   at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:489)
04-04 07:38:25.231 20067 20090 W   System.err                                   at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:435)
04-04 07:38:25.232 20067 20090 W   System.err                                   at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:248)
04-04 07:38:25.233 20067 20090 W   System.err                                   at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getInputStream(DelegatingHttpsURLConnection.java:210)
04-04 07:38:25.234 20067 20090 W   System.err                                   at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getInputStream(Unknown Source:0)
04-04 07:38:25.235 20067 20090 W   System.err                                   at com.mycompany.database.MainActivity$connect.doInBackground(MainActivity.java:42)
04-04 07:38:25.236 20067 20090 W   System.err                                   at com.mycompany.database.MainActivity$connect.doInBackground(Unknown Source:6)
04-04 07:38:25.236 20067 20090 W   System.err                                   at android.os.AsyncTask$2.call(AsyncTask.java:333)
04-04 07:38:25.237 20067 20090 W   System.err                                   at java.util.concurrent.FutureTask.run(FutureTask.java:266)
04-04 07:38:25.238 20067 20090 W   System.err                                   at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
04-04 07:38:25.238 20067 20090 W   System.err                                   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
04-04 07:38:25.239 20067 20090 W   System.err                                   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
04-04 07:38:25.240 20067 20090 W   System.err                                   at java.lang.Thread.run(Thread.java:764)

php 文件

<?php
    require("connect.php");
    $sql = "select * from Med";
    $result = $conn->query($sql);
    $array = array();
    while ($raw = $result->fetch_assoc()) {
        array_push($array,$raw);
    }
    echo json_encode($array)
?>

编辑:我什至尝试将网址替换为 www.google.com，但它显示了相同的错误。

Answer 1

天哪，我太愚蠢了，我忘记了我有一个防火墙应用程序，它禁止新应用程序连接到互联网，我很抱歉浪费了您的时间。