Android MySql：JDBC CommunicationsException

Question

I am using Eclipse and Android Emulator. I can access to 10.0.2.2 in emulator browser. But in my app, this code not run :

Connection con = DriverManager.getConnection("jdbc:mysql://10.0.2.2/stu", "user", "pass");

Anybody has some idea?

The error is :

com.mysql.jdbc.CommunicationsException

I am confused that why i have access to phpMyAdmin in emulator's browser, but not inside the code! :(

Note that full code is this :

public class LearningActivity extends Activity {

private static final String url = "jdbc:mysql://10.0.2.2/stu";
private static final String user = "root";
private static final String pass = "11111";
private Button button;
private TextView tv;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    button = (Button)this.findViewById(R.id.button1);
    tv = (TextView)this.findViewById(R.id.textView1);

    button.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            // Perform action on click
            Connect();
        }
    });
}


private class Connect extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... urls) {
        String response = "";

        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection con = DriverManager.getConnection(url, user, pass);
            // System.out.println("Database connection success");

            String result = "Database connection success\n";
            Statement st = con.createStatement();
            ResultSet rs = st.executeQuery("select * from users");
            ResultSetMetaData rsmd = rs.getMetaData();

            while(rs.next()) {
                result += rsmd.getColumnName(1) + ": " + rs.getInt(1) + "\n";
                result += rsmd.getColumnName(2) + ": " + rs.getString(2) + "\n";
                result += rsmd.getColumnName(3) + ": " + rs.getString(3) + "\n";
            }
            tv.setText(result);
        }
        catch(Exception e) {
            e.printStackTrace();
            tv.setText(e.toString());
        }
        return response;   


    }

    @Override
    protected void onPostExecute(String result) {
        tv.setText(result);
    }
}

public void Connect() {
    Connect task = new Connect();
    task.execute();

}

}

Answer 1

your mysql database should have access from remote system.

You should grant permission for remote access something like this

GRANT ALL PRIVILEGES ON *.* TO 'root'@'192.168.1.%'
    IDENTIFIED BY PASSWORD 'password'  
    WITH GRANT OPTION;
FLUSH PRIVILEGES;

check for more info

Answer 2

Damn it! I missed to add Internet permission to manifest! :( I add that and problem solved.

The browser of phone(android emulator) has this permission and it could connect to network, but my application haven't that permission. So I should add only this line to manifest.xml:

<manifest ... >
.
.
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
.
.
</manifest>

Answer 3

你没有改变ip ...... 1>得到你的机器ip 2>然后连接con = DriverManager.getConnection（“jdbc：mysql：//”your_ip“/ stu”，“user”，“pass”）;