Failed to connect to MySQL database

[eminempark]

Currently I am writing a Java program to connect to the database and here is my program:

import java.io.*;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.border.*;

import java.util.Timer;

import java.util.TimerTask;

import javax.swing.table.*;

import java.sql.*;

import java.util.Date;

import java.util.Calendar;

import java.util.Vector;

import java.text.SimpleDateFormat;

import java.text.ParseException;

import java.lang.String;

import java.text.DecimalFormat;



/**

* these 3 are called form the tinyos.jar,

* and need to be placed in where the

* java\jdk<version>\jre\lib\ext located.

*/

import net.tinyos.packet.*;

import net.tinyos.util.*;

import net.tinyos.message.*;



/*

 *

 * This file is to create tabs, link tabs,

 * and create table in database by asking user input the table name

 *

 */



public class CAS_Main extends JPanel {

	CAS_Sub1 cas_sub1 = new CAS_Sub1();

	credits credits = new credits();

	JLabel label2;



	Connection db = null; // Database

	Statement sql = null; // Statement for database



	static String tablename = new String(); // Used to store table name



	JTextField textfield;



	public CAS_Main() {

   	super(new BorderLayout());

		JTabbedPane tabbedPane = new JTabbedPane();



		JPanel tab0 = new JPanel();

		tab0.add(main_panel());

		tab0.add(cas_sub1.sub_connection(1));

		tab0.add(cas_sub1.sub_stream_data(1));

		tabbedPane.addTab("Main Status", tab0);



		JPanel tab1 = new JPanel();

		tab1.add(credits.credit());

		tab1.add(credits.advisor());

		tab1.add(credits.student());

		tabbedPane.addTab("Credits", tab1);



		// Connect to database by using jdbc driver

		try {

			Class.forName("com.mysql.jdbc.Driver");

		}

		catch (Exception e) {

	  		System.err.println("Cannot reach the database driver.");

	  		System.exit(-1);

		}

		try {

			db = DriverManager.getConnection("jdbc:mysql://localhost:3306/database", "root", "root"); //root, abcd

			sql = db.createStatement();

		}

		catch (Exception e) {

	  		System.err.println("Failed to connect database.");

	  		System.exit(-1);

		}

		add(tabbedPane, BorderLayout.CENTER);

	}



	/* Creating a table by getting user input */

	protected void CreateTable() {

			try {

				tablename = textfield.getText();



				sql.executeUpdate("create table " + tablename + "(pc_timestamp datetime, " +

				"node_id int4, packet_id int4, Temp_val float4, Accel_x float4, Accel_y float4, Accel_z float4, Battery float4);");

				System.out.println("Table "+textfield.getText()+" created.");

				CAS_Sub1.textarea.append("Table "+textfield.getText()+" created.\n");

			}

			catch (Exception e) {

			   	System.err.println("Failed to create table.");

			   	CAS_Sub1.textarea.append("Table "+textfield.getText()+" already exist in database.\n");

			   	System.out.println("Table "+textfield.getText()+" already exist in database.");

		   }

	}





	/* Get user input for table name */

	protected void SetTable() {

		tablename = textfield.getText();

	}



	/* Deleting a table by getting user input */

	protected void DeleteTable() {

			try {

				tablename = textfield.getText();



				sql.executeUpdate("drop table " + tablename);

				System.out.println("Table "+textfield.getText()+" is deleted.");

				CAS_Sub1.textarea.append("Table "+textfield.getText()+" is deleted.\n");

			}

			catch (Exception e) {

			   	System.err.println("Failed to delete table.");

			   	CAS_Sub1.textarea.append("Table "+textfield.getText()+" does not exist in database.\n");

			   	System.out.println("Table "+textfield.getText()+" does not exist in database.");

		   }

	}



	/* Creating panel */

	protected JPanel main_panel() {

		JPanel pane = new JPanel();

		label2 = new JLabel("");

		pane.setBorder(BorderFactory.createTitledBorder("Create Table"));

		JLabel label = new JLabel("Input table name: ");

		textfield = new JTextField("table1", 30);



		JButton button3 = new JButton("Delete Table");

       button3.setVerticalTextPosition(AbstractButton.BOTTOM);

       button3.setHorizontalTextPosition(AbstractButton.CENTER);

       button3.addActionListener(new java.awt.event.ActionListener() {

			public void actionPerformed(ActionEvent e) {

				DeleteTable();

			}

	   });



		JButton button2 = new JButton("Set");

     	button2.setVerticalTextPosition(AbstractButton.BOTTOM);

      	button2.setHorizontalTextPosition(AbstractButton.CENTER);

        button2.addActionListener(new java.awt.event.ActionListener() {

			public void actionPerformed(ActionEvent e) {

				SetTable();

			}

	   });

	   JButton button1 = new JButton("Create Table");

       button1.setVerticalTextPosition(AbstractButton.BOTTOM);

       button1.setHorizontalTextPosition(AbstractButton.CENTER);

       button1.addActionListener(new java.awt.event.ActionListener() {

			public void actionPerformed(ActionEvent e) {

				CreateTable();

			}

	   });





	   pane.add(label);

	   pane.add(textfield);

	   pane.add(button2);

	   pane.add(button1);

	   pane.add(button3);

	   return pane;

	}



}

And I am successfully compile it. But when I run it, It is failed to connect to database:

Failed to connect database.

Please help me...

[Tolls]

Instead of using your own message in those catch blocks, use e.printStackTrace().
That will tell you exactly what went wrong and where.

[AeneasTroy]

I always have to register my driver in order to get it to work, even though most people leave that part out:

        DriverManager.RegisterDriver(new com.jdbc.mysql.Driver());  //I do it here
        db = DriverManager.getConnection(url, user, pass);

[Tolls]

This goes to the thing I said in the other thread.
Do not import the driver directly.
That's the DriverManagers job.

After all, what if you wanted to swap out drivers?