使用Android连接到远程MySQL数据库

Question

我有一个MySQL数据库坐在服务器上。我想知道如何连接到我的远程数据库并将数据显示到我的Android应用程序中。

我知道这是Web服务或直接的方式，但我不知道更多。

我有一个脚本写在Php中，坐在服务器上，可以连接到数据库

$db = mysql_connect("localhost", "UserName", "Password") or die (mysql_error());  
mysql_select_db("NameofDB",$db) or die (mysql_error());

谢谢你的帮助！

Answer 1

Android应用端：

private ArrayList<String> receiveData(String file, ArrayList<NameValuePair> data)
{
    InputStream is = null;
    ArrayList<String> output = new ArrayList<String>();
    String line = null;

    //Connect and obtain data via HTTP.
    try
    {
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://www.blah.com/"+file);
        httppost.setEntity(new UrlEncodedFormEntity(data));
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        is = entity.getContent();

    }
    catch(Exception e)
    {
        Log.e("log_tag", "Error in http connection "+e.toString());
    }

    //Parse data into ArrayList and return.
    try
    {
        BufferedReader reader = 
            new BufferedReader(new InputStreamReader(is,"iso-8859-1"));

        while ((line = reader.readLine()) != null) 
        {
            //Parse data into tokens and removing unimportant tokens.
            StringTokenizer st = new StringTokenizer(line, delims, false);

            while(st.hasMoreTokens())
            {
                String token = st.nextToken();
                output.add(token);
            }
        }

        is.close();
        //Log output of data in LogCat.
        Log.d("DATA","DATA:"+output);

    }
    catch(Exception e)
    {
        Log.e("log_tag", "Error converting result "+e.toString());
    }
    return output;
}

/**
 * Gets all  data from GetAllData.php
 * @return output - ArrayList containing  data.
 */
public ArrayList<String> getAllData(String row)
{
    fileName = "GetAllData.php";

    //Add arguments to arrayList<NameValuePairs> so we can encode the data and send it on.
    ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
    nameValuePairs.add(new BasicNameValuePair("row", row));

    ArrayList<String> output = this.receiveData(fileName, nameValuePairs);
    return output;
}

服务器端：

那么服务器上的GetAllData.php文件是：

<?php
/*
 * What this file does is it:
 * 1) Creates connection to database.
 * 2) Gets data from database.
 * 3) Encodes data to JSON. So this data can then be used by Android Application.
 * 4) Close database connection.
 */
 require_once $_SERVER['DOCUMENT_ROOT'].'/Clarity/Connection.php';
 require_once $_SERVER['DOCUMENT_ROOT'].'/Clarity/ReceiveAPI.php';

 $server = new Connection();
 $receive = new ReceiveAPI();

 //Retrieve information.
 $row = $_POST['row'];

//Connect to database.
$server->connectDB();
$output = $receive->getAllData($row); //basically method to query database.
print(json_encode($output)); //output is result of the query given back to app.

//Disconnect from database.
$server->disconnectDB();
?>

这是我最近使用的一个例子。只是在php文件中注意。我导入Connection.php这只是处理与数据库的连接。所以只需用您的代码替换它以连接到MYSQL db。我也导入了SendAPI.php（您可以忽略）这只是我发送数据的类。基本上它包含了我想要使用的一些查询。比如sendAccelerationData（）。基本上类与存储过程类似。

我如何连接到数据库是在我的Connection.php类中。

//Connect to a database.
public function connectDB()
{
    //Connect to SQL server.
    $this->connection = mysql_connect($this->hostName,$this->user,$this->password);

    if (!$this->connection) 
    {
        die('Could not connect: ' . mysql_error());
    }
    //Print("Connected to MySQL. </br>");

    //Select Database to query.
    $db_selected = mysql_select_db($this->database);
    if (!$db_selected) 
    {
        die('Could not select database' . mysql_error());
    }
    //Print("Database \"$this->database\" selected. </br>");
}

//Disconnect from database.
public function disconnectDB() 
{
    mysql_close($this->connection);
}
}

请注意错误消息我打印出架构输出db，例如db name / table name。这只是故障排除。我反对这个建议。您不希望向用户显示该信息。