[ JSP/JAVA ] MySQL connection fails

White R4bbit · 08-17-2004, 03:35 PM

Hi all,
I've got this problem with JSP and MySQL: when I try to load my jsp page which should connect to the database, I get this error

Code:

java.sql.SQLException: 
Unable to connect to any hosts due to exception: java.security.AccessControlException: 
access denied (java.net.SocketPermission localhost resolve)

If I try accessing the database from Java, with a similar code, it runs correctly.
I have no firewalls blocking connections and I cannot understand why it does work with Java but not with JSP.
I'm using Tomcat as webserver and all the jsp pages that don't use a database run correctly.

Any ideas?

Thank you very much

Jose Muñiz · 08-17-2004, 07:34 PM

Maybe you can show us your code in charge of creating the connection? Are you using the correct username / password combination? Are you sure you have correctly set up the access rights in your database, considering your location?

White R4bbit · 08-18-2004, 04:02 AM

Okay I attach both the Java and the JSP code; I'm not sure I've configured everything correctly, but I have a user "root" with no password and with the Java code it all works perfectly. Are there some other aspects of mysql configuration that I should have checked in order to make it work with tomcat/jsp?
Thank you.

Java code (working):

Code:

import java.awt.*;
import java.sql.*;
import java.util.*;
import javax.swing.*;

public class Provadb extends JFrame {
	
	static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
	static final String DATABASE_URL="jdbc:mysql://localhost:3306/JSPProva";
	
	private Connection connection;
	private Statement statement;
	
	// costruttore
	public Provadb()
	{
		super("Tabella Persone del database JSPProva");
		try{
			//System.setProperty("db2j.system.home", "/usr/share/mysql/");
			Class.forName( JDBC_DRIVER );
			connection = DriverManager.getConnection( DATABASE_URL, "root", "" );
			statement = connection.createStatement();
			
			ResultSet resultSet = statement.executeQuery( "SELECT * FROM Persone" );
			
			StringBuffer results = new StringBuffer();
			ResultSetMetaData metaData = resultSet.getMetaData();
			int numberOfColumns = metaData.getColumnCount();
			
			for(int i=1; i<=numberOfColumns; i++)
				results.append( metaData.getColumnName( i ) + "\t" );
			
			results.append("\n");
			
			while( resultSet.next() ){
				for(int i=1; i<=numberOfColumns; i++)
					results.append( resultSet.getObject( i ) + "\t" );
				
				results.append("\n");
			}
			
			// crea l'interfaccia grafica
			JTextArea textArea = new JTextArea( results.toString() );
			Container container = getContentPane();
			
			container.add( new JScrollPane( textArea ) );
			
			setSize( 500,200 );
			setVisible( true );
		} 
		
		catch( SQLException sqlException ){
			JOptionPane.showMessageDialog( null, sqlException.getMessage(), "Errore nel database...", JOptionPane.ERROR_MESSAGE );
			System.exit( 1 );
		}
		
		catch( ClassNotFoundException classNotFound ){
			JOptionPane.showMessageDialog( null, classNotFound.getMessage(), "Impossibile reperire il driver...", JOptionPane.ERROR_MESSAGE );
			System.exit( 1 );
		}
		
		finally{
			try{
				statement.close();
				connection.close();
			}
			
			catch( SQLException sqlException ){
				JOptionPane.showMessageDialog( null, sqlException.getMessage(), "Errore nel database (finally)...", JOptionPane.ERROR_MESSAGE );
				System.exit( 1 );
			}
			
		}
		
	} // fine del costruttore
	
	public static void main( String args[] )
	{	
		Provadb window = new Provadb();
		window.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
	}
	
}

JSP code (not working):

Code:

<%@ page import="java.sql.*" %>
<%! String DRIVER = "com.mysql.jdbc.Driver";
String DB_URL = "jdbc:mysql://localhost:3306/JSPProva";
%>

<html>

<head> 
<title>Connessione a DB attraverso JDBC</title>
</head>

<body>
  <h1>Accesso ad un database MySQL</h1>
  
  <% 						
  Class.forName(DRIVER);  		// Carico il driver.
  Connection connection = null;	// Preparo il riferimento alla connessione.
   try {						 
  connection = DriverManager.getConnection(DB_URL, "root", "");		// Apro la connesione verso il database.  
  Statement statement = connection.createStatement();	// Ottengo lo Statement per interagire con il database.
  ResultSet resultset = statement.executeQuery(			 // Interrogo il DBMS mediante una query SQL.
  "SELECT Nome, Cognome, Indirizzo FROM Persone");		// Scorro e mostro i risultati.
  while (resultset.next()) {
  String nome = resultset.getString(1);
  String cognome = resultset.getString(2);
  String indirizzo = resultset.getString(3); %>
  <b>Nome:</b> <%= nome %><br>
  <b>Cognome:</b> <%= cognome %><br>
  <b>Indirizzo:</b> <%= indirizzo %><br><br>
  <% 
  }
} // end try
  
  catch (SQLException e) {
 	%><b>Eccezione:</b> <%= e.toString() %><%
  } //end catch
  
  finally {
	if (connection != null) connection.close(); 
  } // end finally 
%>

</body> 

</html>

White R4bbit · 08-18-2004, 08:12 AM

Okay, I fixed it out!
It was a tomcat policy problem. I had to add these lines to /etc/tomcat4/policy.d/04webapps.policy

Code:

 permission java.net.SocketPermission "127.0.0.1:3306", "connect,resolve";
  permission java.util.PropertyPermission "file.encoding", "read";

Hope it can help someone else

Haz · 04-27-2005, 08:31 AM

Hi,

I had the same problem when I updated my version of Tomcat 4 in Debian. As the above quote mentioned I added the following lines to my /etc/tomcat4/policy.d/04webapps.policy file

Code:

permission java.net.SocketPermission "127.0.0.1:3306", "connect,resolve";
permission java.util.PropertyPermission "file.encoding", "read";

and it worked. I also commented out

Code:

#bind-address = 127.0.0.1

in my /etc/mysql/my.cnf

Thanks.