Question

Ok – I found the driver version that goes with the database.. however now I get the following.

Got an exception! Communications link
failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

java.net.ConnectException MESSAGE:
Connection timed out: connect

STACKTRACE:

java.net.ConnectException: Connection
timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native
Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:525)
at java.net.Socket.connect(Socket.java:475)
at java.net.Socket.(Socket.java:372)
at java.net.Socket.(Socket.java:215)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)
at com.mysql.jdbc.MysqlIO.(MysqlIO.java:271)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771)
at com.mysql.jdbc.Connection.(Connection.java:1555)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at freelancebillingapp.customerInfoUI.jButton1MouseClicked(customerInfoUI.java:221)
at freelancebillingapp.customerInfoUI.access$000(customerInfoUI.java:12)
at freelancebillingapp.customerInfoUI$1.mouseClicked(customerInfoUI.java:59)
at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:253)
at java.awt.Component.processMouseEvent(Component.java:6266)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3255)
at java.awt.Component.processEvent(Component.java:6028)
at java.awt.Container.processEvent(Container.java:2041)
at java.awt.Component.dispatchEventImpl(Component.java:4630)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4574)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4247)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
at java.awt.Container.dispatchEventImpl(Container.java:2085)
at java.awt.Window.dispatchEventImpl(Window.java:2475)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

** END NESTED EXCEPTION **

Last packet sent to the server was 1
ms ago.

Answer 1

This may not solve it, but it tells you that someone else has had this problem.

Make sure you have the precise version of JDBC driver to match your version of MySQL.

I would strongly urge you to rewrite your code more like this. You aren’t closing resources properly at all.

Adapt it to your own needs. I created a local MySQL database on my machine and added a customer table. It worked just fine.

package persistence;

import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

public class DatabaseUtils
{
    private static final String URL = "jdbc:mysql://localhost:3306/contacts";
    private static final String USERNAME = "contacts";
    private static final String PASSWORD = "contacts";

    public static final String SELECT_SQL = "select customer_id, name, street, city, state, zip, phone, url from customer order by customer_id";
    public static final String INSERT_SQL = "insert into customer(name, street, city, state, zip, phone, url) values(?,?,?,?,?,?,?)";

    public static void main(String[] args)
    {
        Connection connection = null;

        try
        {
            connection = getConnection(URL, USERNAME, PASSWORD);
            List<Map> rows = findAllCustomers(connection);

            for (Map row : rows)
            {
                System.out.println(row);                    
            }
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
        finally
        {
            close(connection);
        }
    }

    public static List<Map> findAllCustomers(Connection connection) throws SQLException
    {
        List<Map> rows = new ArrayList<Map>();
        PreparedStatement st = null;
        ResultSet rs = null;

        try
        {
            st = connection.prepareStatement(SELECT_SQL);
            rs = st.executeQuery();
            while (rs.next())
            {
                rows.add(map(rs));                
            }
        }
        finally
        {
            close(rs);
            close(st);
        }

        return rows;
    }

    private static Map<String, Object> map(ResultSet rs) throws SQLException
    {
        Map<String, Object> row = new LinkedHashMap<String, Object>();

        ResultSetMetaData meta = rs.getMetaData();

        int numColumns = meta.getColumnCount();
        for (int i = 1; i <= numColumns; ++i)
        {
            String column = meta.getColumnName(i);
            Object value = rs.getObject(i);
            row.put(column, value);
        }

        return row;
    }

    public static Connection getConnection(String url, String username, String password) throws SQLException
    {
        Driver driver = DriverManager.getDriver(url);

        DriverManager.registerDriver(driver);

        return DriverManager.getConnection(url, username, password);
    }

    public static void close(Connection connection)
    {
        try
        {
            if (connection != null)
            {
                connection.close();
            }
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
    }

    public static void close(Statement st)
    {
        try
        {
            if (st != null)
            {
                st.close();
            }
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
    }

    public static void close(ResultSet rs)
    {
        try
        {
            if (rs != null)
            {
                rs.close();
            }
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
    }

    public void rollback(Connection connection)
    {
        try
        {
            if (connection != null)
            {
                connection.rollback();
            }
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
    }
}