Salve a tutti,
premetto che sono alle prime armi con java e probabilmente il mio errore è dovuto alla mia ignoranza in materia.
Il codice che mi restituisce l'errore è il seguente:
codice:
public void eseguiQueryUpdate(String qry){
query = qry; int ru = 0;
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
conn = DriverManager.getConnection(URL,"root","matumba");
ps = conn.prepareStatement(query);
try {
pu.executeUpdate();
}
catch (SQLException e) {
e.printStackTrace();
}
}
catch(Exception ex){
ex.printStackTrace();
}
}
l'errore invece è:
java.lang.NullPointerException
at cavalli.util.dbconn.ManagerConnection.eseguiQueryU pdate(ManagerConnection.java:51)
at cavalli.util.servlet.Registrazione.processData(Reg istrazione.java:98)
at cavalli.util.servlet.Registrazione.doGet(Registraz ione.java:34)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:717)
at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.servic e(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(H ttp11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11Conn ectionHandler.process(Http11Protocol.java:602)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run( JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)
java.lang.NullPointerException
at cavalli.util.dbconn.ManagerConnection.eseguiQueryU pdate(ManagerConnection.java:51)
at cavalli.util.servlet.Registrazione.processData(Reg istrazione.java:109)
at cavalli.util.servlet.Registrazione.doGet(Registraz ione.java:34)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:717)
at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.servic e(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(H ttp11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11Conn ectionHandler.process(Http11Protocol.java:602)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run( JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)
java.lang.NullPointerException
at cavalli.util.dbconn.ManagerConnection.eseguiQueryU pdate(ManagerConnection.java:51)
at cavalli.util.servlet.Registrazione.processData(Reg istrazione.java:120)
at cavalli.util.servlet.Registrazione.doGet(Registraz ione.java:34)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:717)
at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.servic e(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(H ttp11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11Conn ectionHandler.process(Http11Protocol.java:602)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run( JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)
Ho provato a fare una stampa delle query che mi restituiscono le exception ma mi sembrano corrette in tutto e per tutto.
Il DB su cui lavoro è MySql.
Ho davvero bisogno di una mano.
Grazie mille.