February 2004 Technical Tip – Accessing MySQL Databases from Java
Last month I showed you how to set up and use MySQL. This month I will show you how to access MySQL databases from Java. I will provide a complete, working program. This is not intended to be a complete lesson on JDBC (as provided in our Java course), but only to provide the details of how to connect to a MySQL database. Furthermore, I will assume the reader is making use of IBM's WebSphere Studio Application Developer (WSAD) which is the IDE used by most of our clients.
Getting MySQL Connector
Starting the MySQL server
- Start the MySQL server as discussed last month. Recall that we opened a command prompt window and entered the commands cd\minixampp and mysql_start.bat
- Recall that you must not close the window while the MySQL server is running (you can minimize it, but do not close it.)
- If you do not start MySQL, you will get an exception when you try to connect to the database:
java.sql.SQLException: Unable to connect to any hosts due to exception: java.net.ConnectException: Connection refused: connect
- You will, of course, need to create the database and table. We will use database mydatabase, table mytable shown in last month's article.
Adding the JAR file to the build path
- Start WSAD.
- Right click on your Project and from its pop-up menu, select Properties.
- In the Properties dialog, select the Java Build Path page.
- Click the Libraries tag.
- Click the Add External JARs button.
- In the dialog that appears, select the JAR file:
- Key statements:
private static final String DRIVER = "com.mysql.jdbc.Driver";
private static final String SOURCE = "jdbc:mysql://localhost/mydatabase";
- Go to http://www.caliberdt.com/tips/JdbcWithMySQL.java to see full source for a program which reads the table created in last month's article.
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Written by Bill Qualls. Copyright © 2004 by Caliber Data Training 800.938.1222