如何使用HttpUrlConnection通过POST传递参数 [英] How to pass an argument with POST using HttpUrlConnection

问题描述

我发现将OutputStreamWriter包装在BufferedWriter中是引起问题的原因，因此摆脱了包装器的困扰，我的POST通过了.仍然想知道为什么BufferedWriter是原因.

我先向自己道歉，因为我才刚刚开始自学有关数据库，应用程序与服务器/数据库之间的通信以及php的所有知识.

I apologize in advance, as I am just beginning to teach myself all about databases, communication between an app and a server/database, and php.

其他类似问题未提供答案.

Other similar questions asked have not provided an answer.

使用HttpUrlConnection从我的android应用程序到本地托管服务器上的php脚本进行简单POST时，我很难分辨出我所缺少的内容.我需要从android应用程序中获取用户ID，并将其作为参数传递给php脚本，然后在称为用户的数据库表中执行该ID的查找.我也想使用不被弃用的方法和类.

I am having some trouble discerning what I'm missing when it comes to making a simple POST using HttpUrlConnection from my android application to a php script on a locally hosted server. I need to take a user ID from the android application, pass that to the php script as an argument, and perform a lookup of that ID in the database table called users. I also would like to use methods and classes that are not deprecated.

我已在android清单中包含Internet权限.我正在使用XAMPP，并且已经验证我的服务器正在运行，并且如果我通过Web浏览器访问该URL，则会得到我正在寻找的JSON响应.

I have included Internet permissions in the android manifest. I am using XAMPP, and I have verified that my servers are running, and if I access the url through a web browser I get the JSON response I am looking for.

我唯一的logcat消息是IOException，它在写入输出流后立即发生. 特定的例外是意外的流结束" .

My only logcat message is an IOException, which occurs just after writing to the output stream. The specific exception is "unexpected end of stream".

这是我的AsyncTask类中的代码:

Here is the code in my AsyncTask class:

protected String doInBackground(String... params) {

    String userID = params[0];
    Pair<String, String> phpParameter = new Pair<>("userID", userID);
    String result = "";

    try {
        URL url = new URL("url of locally-hosted php script");
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

        // prepare request
        urlConnection.setRequestMethod("POST");
        urlConnection.setDoInput(true);
        urlConnection.setDoOutput(true);
        urlConnection.setReadTimeout(10000);
        urlConnection.setConnectTimeout(15000);
        urlConnection.setFixedLengthStreamingMode(userID.getBytes("UTF-8").length);

        // upload request
        OutputStream outputStream = urlConnection.getOutputStream();
        BufferedWriter writer = new BufferedWriter(
                new OutputStreamWriter(outputStream, "UTF-8"));
        writer.write(phpParameter.first + "=" + phpParameter.second);
        writer.close();
        outputStream.close();

        // read response
        BufferedReader in = new BufferedReader(
                new InputStreamReader(urlConnection.getInputStream()));

        String inputLine;
        StringBuffer response = new StringBuffer();
        while ((inputLine = in.readLine()) != null) { response.append(inputLine); }
        in.close();

        result = response.toString();

        // disconnect
        urlConnection.disconnect();
    } catch (MalformedURLException e) {
        Log.e("Malformed URL Exception", "Malformed URL Exception");
    } catch (IOException e) {
        Log.e("IOException", "IOException");
    }

    return result;
}

这是服务器上的我的php脚本.对于准备好的语句，我也需要一些帮助，所以不要因为'id = 1'而惹恼我:

And here is my php script on the server. I also need a little help with prepared statements, so don't beat me up over the 'id = 1':

<?php

mysql_connect("host","username","password");

mysql_select_db("Database");

print($_POST);

$sql = mysql_query("select * from users where id = 1");

while($row = mysql_fetch_assoc($sql))
$output[] = $row;

print(json_encode($output)); // this will print the output in json
mysql_close();

?>

推荐答案

好像我已将其修复！

我改变了

BufferedWriter writer = new BufferedWriter(
            new OutputStreamWriter(outputStream, "UTF-8"));
writer.write(phpParameter.first + "=" + phpParameter.second);

到

OutputStreamWriter writer = new OutputStreamWriter(outputStream, "UTF-8");
writer.write(userID);

由于某种原因，将输出流写入器包装在缓冲写入器中的行为破坏了它.我不知道为什么.

For some reason, the act of wrapping the output stream writer in a buffered writer was breaking it. I don't know why.

进行了上述更改后，我收到一条错误消息，说该流原本需要1个字节，但接收到8个字节，所以我只写了userID，这是我始终传递给setFixedLengthStreamingMode的内容.

Once I made the above change, I received an error saying that the stream was expecting 1 byte but received 8, so I wrote only userID, which is what I passed to setFixedLengthStreamingMode anyway.

这篇关于如何使用HttpUrlConnection通过POST传递参数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！