java - 如何从php读取字符串到android studio(java)

Question

我不知道为什么当我调用 GetPHPData() 函数时会得到空值。 “out”变量不返回任何内容(“”)。我做了一个 Toast.makeTest 它返回空字符串。请帮忙。这是我的代码:

public class PHPConnect extends  Activity
{
    String url = "http://122.2.8.226/MITBookstore/sqlconnect.php";
    HttpURLConnection urlConnection = null;
    String out = null;
    public String GetPHPData()
    {
        try {

            urlConnection = (HttpURLConnection) new URL(url).openConnection();
            urlConnection.setConnectTimeout(5000);
            urlConnection.setReadTimeout(10000);
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        try
        {
            BufferedReader in = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
            out = readStream(in);
        }
        catch (Exception e)
        {
            Toast.makeText(getApplicationContext(),e.getMessage(),Toast.LENGTH_SHORT).show();
        }
        finally
        {
            urlConnection.disconnect();
            return out;
        }

    }
    private String readStream(BufferedReader is)
    {
        try
        {
            ByteArrayOutputStream bo = new ByteArrayOutputStream();
            int i = is.read();
            while(i != -1)
            {
                bo.write(i);
                i = is.read();
            }
            return bo.toString();
        } catch (IOException e)
        {
            return e.getMessage();
        }
    }
}

顺便说一下，我正在运行一个 wamp 服务器，并且我端口转发了我的路由器，在本地主机上，该 url 有效，但在远程连接上，它不会返回字符串。你可以尝试一下这个url，结果是:“This is the output:emil”

Answer 1

您能否尝试下面一段对我有用的代码，并在 android list 文件中添加 INTERNET 权限。如果仍然无法正常工作，则可能是服务器端出现问题，然后尝试调试它。

URL url;
    try {
        url = new URL("myurl");

        HttpURLConnection urlConnection = (HttpURLConnection) url
                .openConnection();

        InputStream in = urlConnection.getInputStream();

        InputStreamReader isw = new InputStreamReader(in);

        int data = isw.read();
        while (data != -1) {
            char current = (char) data;
            data = isw.read();
            System.out.print(current);
        }
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }