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Thread: Connection to MySql Database

  1. #1
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    Default Connection to MySql Database

    Hi,

    I'm just trying to get a simple connection going to my database. The database is fine but when I run my java program, all I see is, "Build Successful". I would like to display the information I put in my table. Thanks.

     
     
    import java.sql.*;
     
    public class TestSQL {
     
        public static void main(String args[]) {
            try {
     
                // Load the JDBC driver
                Class.forName("src.com.mysql.jdbc.Driver");
                System.out.println("---Driver loaded---");
     
                //Establish Connection
                Connection connection = DriverManager.getConnection(
                        "jdbc:mysql://localhost/test", "username", "password");
     
                //Create a Statement
                Statement statement = connection.createStatement();
     
                //Execute a Statement
                ResultSet rs = statement.executeQuery("SELECT * FROM people");
     
                //Iterate through the results and display data
                while(rs.next()){
     
                    System.out.println(rs.getString(1) + rs.getString(2));
                }
     
     
                //Close connection
                connection.close();
     
     
     
            } catch (Exception e) {
     
                e.getMessage();
            }
     
        }
    }


  2. #2
    Super Moderator copeg's Avatar
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    Default Re: Connection to MySql Database

    all I see is, "Build Successful"
    Did you execute the main class file? I only ask since this statement makes me think you compiled but didn't run the program. If you did run and didn't see anything, use println to debug, and especially when catching exceptions print something out that might be meaningful (such as e.printStackTrace()). If you do get an exception and don't understand please post back the full error message.

  3. #3
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    Default Re: Connection to MySql Database

    Im using Netbeans so Im compiling and then running.
    I took your suggestion to printStackTrace and i get the following error.
    java.lang.ClassNotFoundException: src.com.mysql.jdbc.Driver
    	at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    	at java.security.AccessController.doPrivileged(Native Method)
    	at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
    	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
    	at java.lang.Class.forName0(Native Method)
    	at java.lang.Class.forName(Class.java:169)
    	at TestSQL.main(TestSQL.java:13)

    Just to let you know as well, I've already downloaded the Connection Driver and placed the folder in "/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/lib"

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Connection to MySql Database

    ClassNotFoundException: src.com.mysql.jdbc.Driver
    The JVM can not find the class shown in the error message.
    Are you sure that is the correct name for the class?
    Is the class file on the classpath where the JVM can find it?

    Sorry I don't know anything about using Netbeans.

  5. #5
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    Default Re: Connection to MySql Database

    I think i have to change my class path, but Im not sure how to do this on mac. Ive been reading my text book and it suggests, "To use the MySQL and Oracle drivers, you have to add mysqljdbc.jar and ojdbc6.jar in the classpath using the following DOS command on Windows:
    set classpath=%classpath%;c:\book\mysqljdbc.jar;c:\boo k\ojdbc6.jar" ...If anyone knows what the equivalent command for unix is, I think that should solve the problem

  6. #6
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    Default Re: Connection to MySql Database

    Hi All,

    I finally figured out the problem, or at least one possible solution. In Netbeans you have to supply the path to the connection driver (JAR) from the projects properties.sql.jpg

  7. #7
    Super Moderator copeg's Avatar
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    Default Re: Connection to MySql Database

    For what its worth, I'd recommend not placing the driver .jar in the JDK lib folder...imagine updating your jdk and poof...that lib folder gets wiped and all your projects break as a result.

  8. The Following User Says Thank You to copeg For This Useful Post:

    dego89 (May 25th, 2011)

  9. #8
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    Default Re: Connection to MySql Database

    Thanks, I realize this is a temporary fix. If I find a better suited solution I will post back.

  10. #9
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    Default Re: Connection to MySql Database

    My final solution was to keep the driver (JAR) in the project folder. many thanks again.

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