Connecting to MySQL from Android with JDBC

Question

I used the following code to connect MySQL in localhost from Android. It only displays the actions given in catch section . I do not know whether it is a connection problem or not.

package com.test1;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class Test1Activity extends Activity {
    /** Called when the activity is first created. */
    String str="new";
    static ResultSet rs;
    static PreparedStatement st;
    static Connection con;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        final   TextView tv=(TextView)findViewById(R.id.user);

        try
        {
            Class.forName("com.mysql.jdbc.Driver");
              con=DriverManager.getConnection("jdbc:mysql://10.0.2.2:8080/example","root","");
            st=con.prepareStatement("select * from country where id=1");
            rs=st.executeQuery();
             while(rs.next())
             {
             str=rs.getString(2);


             }


            tv.setText(str);
            setContentView(tv);
        }
        catch(Exception e)
        {
            tv.setText(str);
        }
    }
}

When this code executes it displays "new" in the avd.

java.lang.management.ManagementFactory.getThreadMXBean, referenced from method com.mysql.jdbc.MysqlIO.appendDeadlockStatusInformation
Could not find class 'javax.naming.StringRefAddr', referenced from method com.mysql.jdbc.ConnectionPropertiesImpl$ConnectionProperty.storeTo
Could not find method javax.naming.Reference.get, referenced from method com.mysql.jdbc.ConnectionPropertiesImpl$ConnectionProperty.initializeFrom

Can anyone suggest some solution? And thanks in advance

Answer 1

You can't access a MySQL DB from Android natively. EDIT: Actually you may be able to use JDBC, but it is not recommended (or may not work?) ... see Android JDBC not working: ClassNotFoundException on driver

See

http://www.helloandroid.com/tutorials/connecting-mysql-database

http://www.basic4ppc.com/forum/basic4android-getting-started-tutorials/8339-connect-android-mysql-database-tutorial.html

Android cannot connect directly to the database server. Therefore we need to create a simple web service that will pass the requests to the database and will return the response.

http://codeoncloud.blogspot.com/2012/03/android-mysql-client.html

For most [good] users this might be fine. But imagine you get a hacker that gets a hold of your program. I've decompiled my own applications and its scary what I've seen. What if they get your username / password to your database and wreak havoc? Bad.

Answer 2

this code runs permanently!!! created by diko(Turkey)

public void mysql() {

    try {
        Class.forName("com.mysql.jdbc.Driver");
    } catch (ClassNotFoundException e) {
        e.printStackTrace();

    }

    thrd1 = new Thread(new Runnable() {
        public void run() {
            while (!Thread.interrupted()) {
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e1) {

                }
                if (con == null) {
                    try {
                        con = DriverManager.getConnection("jdbc:mysql://192.168.1.45:3306/deneme", "ali", "12345");

                    } catch (SQLException e) {
                        e.printStackTrace();
                        con = null;
                    }

                    if ((thrd2 != null) && (!thrd2.isAlive()))
                        thrd2.start();

                }
            }

        }
    });
    if ((thrd1 != null) && (!thrd1.isAlive())) thrd1.start();

    thrd2 = new Thread(new Runnable() {
        public void run() {
            while (!Thread.interrupted()) {

                if (con != null) {
                    try {
                     //   con = DriverManager.getConnection("jdbc:mysql://192.168.1.45:3306/deneme", "ali", "12345");
                        Statement st = con.createStatement();
                        String ali = "'fff'";
                        st.execute("INSERT INTO deneme (name) VALUES(" + ali + ")");
                      //  ResultSet rs = st.executeQuery("select * from deneme");
                      //  ResultSetMetaData rsmd = rs.getMetaData();
                      //  String result = new String();


                      //  while (rs.next()) {
                      //      result += rsmd.getColumnName(1) + ": " + rs.getInt(1) + "\n";
                     //       result += rsmd.getColumnName(2) + ": " + rs.getString(2) + "\n";


                     //   }

                    } catch (SQLException e) {
                        e.printStackTrace();
                        con = null;
                    }

                    try {
                        Thread.sleep(10);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                } else {
                    try {
                        Thread.sleep(300);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

    });


}