εχω το παρακατω παραδειγμα το οποιο θα ηθελα να τρεξω (το οποιο ειναι απο το βιβλιο "Java How to Program απο Deitel&Deitel" Κεφαλαιο 25 στην 7η edition σελιδα 1176 )
- Κώδικας: Επιλογή όλων
// Fig. 25.23: DisplayAuthors.java
// Displaying the contents of the authors table.
import java.sql.Connection;
import java.sql.Statement;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
public class DisplayAuthors
{
// JDBC driver name and database URL
static final String DRIVER = "com.mysql.jdbc.Driver";
static final String DATABASE_URL = "jdbc:mysql://localhost/library";
// launch the application
public static void main( String args[] )
{
Connection connection = null; // manages connection
Statement statement = null; // query statement
ResultSet resultSet = null; // manages results
// connect to database books and query database
try
{
// load the driver class
Class.forName( DRIVER );
// establish connection to database
connection =
DriverManager.getConnection( DATABASE_URL, "< username μου>", "<το pass μου>" );
// create Statement for querying database
statement = connection.createStatement();
// query database
resultSet = statement.executeQuery(
"SELECT AUTHOR_CODE, AUTHOR_NAME, AUTHOR_SURNAME FROM author" );
// process query results
ResultSetMetaData metaData = resultSet.getMetaData();
int numberOfColumns = metaData.getColumnCount();
System.out.println( "Authors Table of Books Database:\n" );
for ( int i = 1; i <= numberOfColumns; i++ )
System.out.printf( "%-8s\t", metaData.getColumnName( i ) );
System.out.println();
while ( resultSet.next() )
{
for ( int i = 1; i <= numberOfColumns; i++ )
System.out.printf( "%-8s\t", resultSet.getObject( i ) );
System.out.println();
} // end while
} // end try
catch ( SQLException sqlException )
{
sqlException.printStackTrace();
} // end catch
catch ( ClassNotFoundException classNotFound )
{
classNotFound.printStackTrace();
} // end catch
finally // ensure resultSet, statement and connection are closed
{
try
{
resultSet.close();
statement.close();
connection.close();
} // end try
catch ( Exception exception )
{
exception.printStackTrace();
} // end catch
} // end finally
} // end main
} // end class DisplayAuthors
αλλα μου πεταει το εξης error:
- Κώδικας: Επιλογή όλων
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at DisplayAuthors.main(DisplayAuthors.java:24)
java.lang.NullPointerException
at DisplayAuthors.main(DisplayAuthors.java:58)
Υπαρχει καποιο προβλημα με το LAMPP ή καποια configuration που χρειαζεται να κανω?πχ βρηκα αυτο-->https://help.ubuntu.com/community/JDBCAndMySQL αλλα δεν λειτουργει.
Καμια ιδεα ?
