使用Java连接到MySQL数据库

Question

So I just started learning about databases this week and one of the things I need to be able to do is connect to my mySQL database that I created using Java. I have done some research and I have tried to find the correct way of doing this I just can't seem to figure out how. Here is my code:

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
 public class Menu
 {
public void menu()
{
    Connection conn;
    String url = "jdbc:mysql://localhost:3306/";
    String dbName = "gym";
    String driver = "com.mysql.jdbc.Driver";
    String userName = "root";
    String password = "password";
    try 
    {
        Class.forName(driver).newInstance();
        conn = DriverManager.getConnection(url+dbName,userName,password);
        System.out.println("Connected to the database");
        conn.close();
        System.out.println("Disconnected from database");
    } 
    catch (Exception e) 
    {
        System.out.println("NO CONNECTION =(");
        System.out.println(e.getMessage());
    }
  }

}

Now the problem is, is that every time I run this code, the "No Connection =( " appears and then it says the error is: "com.mysql.jdbc.Driver". Can somebody please help me and say what I am doing wrong? Thank you. Much appreciated.

Answer 1

Your error means that your library path doesn't contain the jar that contains the com.mysql.jdbc.Driver class.

You don't have to change anything in your code. If you are running it via Eclipse, you should add mysql-connector-java-xxx-bin.jar to your build path (where xxx is the version of the jar).

Answer 2

All JDBC connection classes need their respective drivers which are normally supplied as jar files from the database vendor, add the relevant database driver to your classpath.

The .jar file will be available from the vendors site, in this case : http://www.mysql.com/products/connector/ and then to add this to the classpath of your project in the ide of your choice. Here is a guide for eclipse : http://www.wikihow.com/Add-JARs-to-Project-Build-Paths-in-Eclipse-(Java)

Try and run again once you have this.