Re: Null pointer

Hi

Thks very much. I follow your suggestions. It's OK now



On 23 mai, 14:48, Trevor Skaife <tska...@gmail.com> wrote:
> To add to what Thad said, your map should look like this "Map<String,
> String> formData" since the key of the map looks like a String, and your
> just doing a toString on the value. So when you create your map it should
> probably look something like this.
>
> Map<String, String> formData = new HashMap<String, String>();
>
> It's really important that you type any collection object (Map, Set, List,
> ...) since your compiled code will be huge, and it save a lot of casting of
> objects. Not to mention being able to easily loop through collections using
> the a for-each loop like so.
>
> List<String> items = new ArrayList<String>();
> //add items to the list.
>
> for(String item : items)
>      print(item);
>
> Lastly using the debugger is your friend. The possible items that could be
> null are formData, formData.get("username"), and stmt. My guess is that
> either your map is null, or your map doesn't contain "username".
>
> Trevor
>
>
>
> On Wednesday, May 23, 2012 2:12:22 AM UTC-5, SCK wrote:
>
> > Hi
>
> >  I try to connect to my database with GWT RPC. But i get a error.
>
> > Help please
>
> > Thks
>
> > java.lang.NullPointerException
> >         at
> > org.etude.gwt.server.DatabaseServiceImpl.saveData(DatabaseServiceImpl.java:
>
> > 37)
> >         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.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:
> > 569)
> >         at
> > com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServi­ceServlet.java:
>
> > 208)
> >         at
> > com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServi­ceServlet.java:
>
> > 248)
> >         at
> > com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(Abstract­RemoteServiceServlet.java:
>
> > 62)
> >         at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
> >         at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
> >         at
> > org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:
> > 487)
> >         at
> > org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:
> > 362)
> >         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:
> > 729)
> >         at
> > org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:
> > 405)
> >         at
> > org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
> > 152)
> >         at
> > org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:
> > 49)
> >         at
> > org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
> > 152)
> >         at org.mortbay.jetty.Server.handle(Server.java:324)
> >         at
> > org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:
> > 505)
> >         at org.mortbay.jetty.HttpConnection
> > $RequestHandler.content(HttpConnection.java:843)
> >         at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
> >         at
> > org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)
> >         at
> > org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
> >         at
> > org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:
> > 395)
> >         at org.mortbay.thread.QueuedThreadPool
> > $PoolThread.run(QueuedThreadPool.java:488)
>
> > package org.etude.gwt.server;
>
> > import java.net.URLDecoder;
> > import java.sql.Connection;
> > import java.sql.DriverManager;
> > import java.sql.PreparedStatement;
> > import java.sql.Statement;
> > import java.util.Map;
>
> > import org.etude.gwt.client.DatabaseService;
>
> > import com.google.gwt.user.server.rpc.RemoteServiceServlet;
>
> > public class DatabaseServiceImpl extends RemoteServiceServlet
> > implements
> >                 DatabaseService {
>
> >         /**
> >          *
> >          */
> >         private static final long serialVersionUID = 1L;
>
> >         @SuppressWarnings("rawtypes")
> >         @Override
> >         public void saveData(Map formData) throws IllegalArgumentException
> > {
>
> >                 try{
> >                         Class.forName("com.mysql.jdbc.Driver");
> >                         Connection conn =
> > DriverManager.getConnection("jdbc:mysql://
> > localhost:3306/oracle", "root", "");
>
> >                         Statement st = conn.createStatement();
>
> >                         //avec décodage
> >                         StringBuffer sqlQuery = new StringBuffer("insert
> > into
> > gwtusers(username,password,email,phone)");
> >                         sqlQuery.append("values(?,?,?,?)");
>
> >                         PreparedStatement stmt =
> > conn.prepareStatement(sqlQuery.toString());
> >         LINE 37
> > stmt.setString(1,URLDecoder.decode(formData.get("username").toString(),"UTF­-8"));
>
> > stmt.setString(2,URLDecoder.decode(formData.get("password").toString(),"UTF­-8"));
>
> > stmt.setString(3,URLDecoder.decode(formData.get("email").toString(),"UTF-8"­));
>
> > stmt.setString(4,URLDecoder.decode(formData.get("phone").toString(),"UTF-8"­));
>
> >                         stmt.execute();
>
> >                         //sans décodage
> >                         st.executeQuery("insert into gwtusers values
> > ('"+formData.get("username").toString()+
> >                                         "','"+formData.get("password").toString()+
>
> >                                         "','"+formData.get("email").toString()+
>
> >                                         "','"+formData.get("phone").toString()+"')");
>
> >                         conn.close();
> >                         //stmt.close();
> >                         //st.close();
>
> >                 }catch(Exception e){
> >                         e.printStackTrace();
> >                 }
>
> >         }
>
> > }
>
> On Wednesday, May 23, 2012 2:12:22 AM UTC-5, SCK wrote:
>
> > Hi
>
> >  I try to connect to my database with GWT RPC. But i get a error.
>
> > Help please
>
> > Thks
>
> > java.lang.NullPointerException
> >         at
> > org.etude.gwt.server.DatabaseServiceImpl.saveData(DatabaseServiceImpl.java:
>
> > 37)
> >         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.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:
> > 569)
> >         at
> > com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServi­ceServlet.java:
>
> > 208)
> >         at
> > com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServi­ceServlet.java:
>
> > 248)
> >         at
> > com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(Abstract­RemoteServiceServlet.java:
>
> > 62)
> >         at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
> >         at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
> >         at
> > org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:
> > 487)
> >         at
> > org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:
> > 362)
> >         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:
> > 729)
> >         at
> > org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:
> > 405)
> >         at
> > org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
> > 152)
> >         at
> > org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:
> > 49)
> >         at
> > org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
> > 152)
> >         at org.mortbay.jetty.Server.handle(Server.java:324)
> >         at
> > org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:
> > 505)
> >         at org.mortbay.jetty.HttpConnection
> > $RequestHandler.content(HttpConnection.java:843)
> >         at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
> >         at
> > org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)
> >         at
> > org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
> >         at
> > org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:
> > 395)
> >         at org.mortbay.thread.QueuedThreadPool
> > $PoolThread.run(QueuedThreadPool.java:488)
>
> > package org.etude.gwt.server;
>
> > import java.net.URLDecoder;
> > import java.sql.Connection;
> > import java.sql.DriverManager;
> > import java.sql.PreparedStatement;
> > import java.sql.Statement;
> > import java.util.Map;
>
> > import org.etude.gwt.client.DatabaseService;
>
> > import com.google.gwt.user.server.rpc.RemoteServiceServlet;
>
> > public class DatabaseServiceImpl extends RemoteServiceServlet
> > implements
> >                 DatabaseService {
>
> >         /**
> >          *
> >          */
> >         private static final long serialVersionUID = 1L;
>
> >         @SuppressWarnings("rawtypes")
> >         @Override
> >         public void saveData(Map formData) throws IllegalArgumentException
> > {
>
> >                 try{
> >                         Class.forName("com.mysql.jdbc.Driver");
>
> ...
>
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>
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