GWT with database connection

[Kiran Panchal]

hello friends someone please tell me how to connnect GWT application with MS SQL Database? do we have to coonect with RPC or we can directly connect???

[Maneesh Godbole]

Kiran,
Welcome to the Ranch.

Have you worked on GWT before? If not check out the FAQ http://faq.javaranch.com/java/GWTFaq which has some links to help you get started
Logically, and I am not talking technical feasibility, if you connect your client directly to the DB, how would you handle scenarios where you would have multiple clients manipulating the same data at the same time?

[Kiran Panchal]

thanks for reply
i have done some demo application in GWT but when i m doing database connection in server in service implementation file it gives error as

java.security.AccessControlException: access denied (java.io.FilePermission C:\DOCUME~1\....\LOCALS~1\Temp read)
at DirverManager.getConnection()

do i have to make any changes to my gwt.xml file or any other configuration change???

[Maneesh Godbole]

The class which has DriverManager.getConnection(), is it on the client or server?

[Kiran Panchal]

this is my code at server side ...

package com.example.server;

import java.sql.*;

import com.example.server.DB_Conn;
import com.example.client.GreetingService;
import com.example.shared.FieldVerifier;
import com.google.gwt.user.server.rpc.RemoteServiceServlet;

/**
 * The server side implementation of the RPC service.
 */
@SuppressWarnings("serial")
public class GreetingServiceImpl extends RemoteServiceServlet implements
		GreetingService {
	private java.sql.Connection con = null; 
    	public String greetServer(String input) throws IllegalArgumentException {
        		
        try { 
            displayData +="Before Class Load! <br> ";

            Class.forName("net.sourceforge.jtds.jdbc.Driver").newInstance();

            displayData +="Before Connection! <br> ";
            con = DriverManager.getConnection("jdbc:jtds:sqlserver://ServerName /databaseName","username","password"); 
            
            displayData +="After Connection! <br> ";
            if (con != null) 
                    System.out.println("Connection Successful!"); 
            displayData +="Connection Successful!";
    } catch (Exception e) { 
            e.printStackTrace(); 
            System.out.println("Error Trace in getConnection() : "  + e.getMessage());
            displayData +="Error Trace in getConnection() : "  + e.getMessage();
            
    }
		
    java.sql.DatabaseMetaData dm = null; 
    java.sql.ResultSet rs = null; 
    try { 

            if (con != null) { 
                    dm = con.getMetaData(); 
                    
                    System.out.println("Driver Information"); 
                    displayData+="Driver Information";
                    System.out.println("\tDriver Name: " + dm.getDriverName()); 
                    displayData+="\tDriver Name: " + dm.getDriverName();
                    
                    System.out.println("\tDriver Version: " + dm.getDriverVersion()); 
                    System.out.println("\nDatabase Information "); 
                    System.out.println("\tDatabase Name: " 
                                    + dm.getDatabaseProductName()); 
                    System.out.println("\tDatabase Version: " 
                                    + dm.getDatabaseProductVersion()); 
                    System.out.println("Avalilable Catalogs "); 
                    rs = dm.getCatalogs(); 
                    while (rs.next()) { 
                            System.out.println("\tcatalog: " + rs.getString(1)); 
                    displayData+="\tcatalog: " + rs.getString(1);
                    } 
                    rs.close(); 
                    rs = null; 
                    //closeConnection(); 
            } else 
                    System.out.println("Error: No active Connection"); 
    } catch (Exception e) { 
            e.printStackTrace(); 
    } 
    dm = null; 


		String serverInfo = getServletContext().getServerInfo();
		String userAgent = getThreadLocalRequest().getHeader("User-Agent");
		return " Display " + displayData 
	}
	
	
	
}

[Maneesh Godbole]

UseCodeTags

Can you please post the full stack trace?
Also can you ensure the oracle driver jar is on your class path? Is it under your WEB-INF/lib?

[Kiran Panchal]

this is error i got

java.security.AccessControlException: access denied (java.io.FilePermission C:\DOCUME~1\73065\LOCALS~1\Temp read)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkPermission(DevAppServerFactory.java:166)
at java.lang.SecurityManager.checkRead(Unknown Source)
at java.io.File.isDirectory(Unknown Source)
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.unpackProperties(ConnectionJDBC2.java:1239)
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.<init>(ConnectionJDBC2.java:269)
at net.sourceforge.jtds.jdbc.ConnectionJDBC3.<init>(ConnectionJDBC3.java:50)
at net.sourceforge.jtds.jdbc.Driver.connect(Driver.java:184)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.example.server.GreetingServiceImpl.greetServer(GreetingServiceImpl.java:66)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:562)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:188)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:224)
at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:713)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:51)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:121)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:712)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:352)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
at org.mortbay.jetty.Server.handle(Server.java:313)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:506)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:844)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:644)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:396)
at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:442)
Error Trace in getConnection() : access denied (java.io.FilePermission C:\DOCUME~1\73065\LOCALS~1\Temp read)
Error: No active Connection

[Henry Kaldera]

Does the Data Source is with in the same domain ? SOP
Dave you configured your driver , driver libs property ?