Question

I’m trying to connect to mysql database from my android application.

I’m getting Communications link failure error.
Below is the code snippet:

public class MySqlConnector {
    private Connection con = null;
    private String s = "";
    private String username = "root";
    private String password = "password01";
    private String connectionString;

    public String ConnectToDb() {
         connectionString ="jdbc:mysql://192.168.1.104:3306/mydatabase";
        //connectionString="jdbc:mysql://10.0.0.0:3306/mydatabase";
        // connectionString="jdbc:mysql://127.0.0.1:3306/mydatabase";
        //connectionString = "jdbc:mysql://MainSrv04:3306/mydatabase";
        // connectionString="jdbc:mysql://localhost:3306/mydatabase";

        // connectionString =
        // "jdbc:mysql://localhost:3306/mydatabase?user=root&password=password01&useUnicode=true&characterEncoding=UTF-8";

        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();

        } catch (Exception ex) {
            ex.printStackTrace();
        }
        try {
            con = DriverManager.getConnection(connectionString, username,
                    password);

            Statement st = con.createStatement();
            String sql = "SELECT First_Name FROM mydatabase.custinfo where CardNumber=5325784707";
            ResultSet rs = st.executeQuery(sql);
            s = rs.getString("First_Name");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (con != null) {
                try {
                    con.close();
                    Log.i("MySqlConnector", "Database connection terminated");
                } catch (Exception e) { /* ignore close errors */
                }
            }
        }

        if (s == "") {
            s = "No Result";
        }
        Log.i("MySqlConnector : s=", s);

        return s;
    }
}

---

I tried all possible combinations as showed in comments and getting following error in caused by field in logcat:

• while using localhost –> Caused by: java.net.ConnectException: localhost/127.0.0.1:3306 - Connection refused
• while using 127.0.0.1 –> Caused by: java.net.ConnectException: /127.0.0.1:3306 - Connection refused
• while using 10.0.0.0 –> Caused by: java.net.SocketException: The operation timed out
• while using 192.168.1.104 –> Caused by: java.net.SocketException: The operation timed out
• while using MainSrv04 –> Caused by: java.net.UnknownHostException: MainSrv04

---

I also pinged mysql port through telnet and it’s working.
Also, I have taken care of privileges.

But still I’m getting Communications link failure error.

Any help appreciated.

Answer 1

Is android application is on same ntework? If not

jdbc:mysql://192.168.1.104:3306

and

jdbc:mysql://10.0.0.0:3306

will not work.

Give the proper network address of mysql.