使用Android连接到远程MySQL数据库 [英] Connect to a remote MySQL database using Android

问题描述

我在服务器上有一个MySQL数据库.我想知道如何连接到远程数据库并将数据显示到我的android应用中.

I have a MySQL database sitting in a server. I would like to know how I could connect to my remote DB and show the data into my android app.

我知道这是WebService或Direct的一种方式，但是我不知道那么多.

I know that is a way with WebService or direct but i don't know more then that.

我有一个写在Php中的脚本，它位于服务器中，可以连接到数据库

I have a script write in Php that sitting in the server that letting connect to the db

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

感谢您的帮助！

推荐答案

Android应用端:

Android app side:

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:

因此服务器上的GetAllData.php文件为:

so then the GetAllData.php file on server is:

<?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();
?>

这是我最近使用的示例.只是在php文件中要注意.我导入Connection.php 这只是处理与数据库的连接.因此，只需将其替换为用于连接到MYSQL db的代码即可.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，它包含一些我想使用的查询.如sendAccelerationData().基本上，类类似于存储过程.

This is an example I used recently. Just to note in the php file. I import Connection.php this just deals with the connection to the database. So just replace that with your code for connecting to MYSQL db. Also I imported SendAPI.php (which you can just ignore)This was just my class for sending data. Basically it contained some of the querys I wanted to use. Such as sendAccelerationData(). Basically class was similar to that of stored procedures.

我如何连接数据库是在Connection.php类中.

How I connected to database was in my Connection.php class.

//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);
}
}

在错误消息中请注意，我已打印出模式db，例如db name/table name.这只是故障排除.我反对这一建议.您不想向用户显示该信息.

Note in error messages I printed out schema out db such as db name/table name. This was just troubleshooting. I advice against this. YOU DO NOT want to display that information to the user.

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