har 2 submit knapper hvis jeg udkommentere den ene i min Servlet virker det fint

dette giver nullpoint exception

    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
       

    //her er problemet
        if(request.getParameter("indsend").equals("indsend")) {
            System.out.println(true);
            response.sendRedirect("controller.jsp");
        }
       
        System.out.println(request.getParameter("indsend"));
       
        System.out.println("hent data "+request.getParameter("hent data"));
       
       
        //denne kode henter data fra hmtlside tabellen
        if(request.getParameter("hent data").equals("hent data")){
        System.out.println("kommer her");
            Connection con = null;
        int id;
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            con = DriverManager.getConnection("jdbc:mysql:///flex", "root",
                    "d");

            if (!con.isClosed())
                System.out.println("Successfully connected to "
                        + "MySQL server using TCP/IP...");
            String i = request.getParameter("group");
            id    = new Integer(i).intValue();
           
            PreparedStatement ps = con.prepareStatement("select title,overskrift,tekst from htmlside where id = ?");
            ps.setInt(1, id);
           
            ResultSet res = ps.executeQuery();
            String title ="";
            String overskrift ="";
            String tekst = "";
            while(res.next()) {
            title = res.getString("title");
            overskrift = res.getString("overskrift");
            tekst = res.getString("tekst");   
            }
           
            HttpSession ses = request.getSession();
           
            ses.setAttribute("tekst", tekst);
            ses.setAttribute("title", title);
            ses.setAttribute("overskrift", overskrift);
            ses.setAttribute("radioButtonId", id + "");
           

        } catch (Exception e) {
            System.err.println("Exception: " + e.getMessage());
        } finally {
            try {
                if (con != null)
                    con.close();
            } catch (SQLException e) {
            }
        }//end hent data

I hvilken linie får du den NullPointerException ?

java.lang.NullPointerException
    servlets.ControllerServlet.doPost(ControllerServlet.java:103)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

java.lang.NullPointerException
    at servlets.ControllerServlet.doPost(ControllerServlet.java:103)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(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.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Unknown Source)

java.lang.NullPointerException
    servlets.ControllerServlet.doPost(ControllerServlet.java:100)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717

Og hvilke linier er linie 100 og linie 103 ?

jeg er lost hvordan får jeg eclipse til at vise linie numre

Når du står på en linie vises linie og kolonne nummer nede i bunden.

Pil ned indtil du når det rigtige nummer.

package servlets;

import java.io.IOException;
import java.sql.*;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
* Servlet implementation class ControllerServlet
*/
public class ControllerServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
    * @see HttpServlet#HttpServlet()
    */
    public ControllerServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
    *      response)
    */
    @Override
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
//        Connection con = null;
//        int id;
//        try {
//            Class.forName("com.mysql.jdbc.Driver").newInstance();
//            con = DriverManager.getConnection("jdbc:mysql:///flex", "root",
//                    "vlot9024");
//
//            if (!con.isClosed())
//                System.out.println("Successfully connected to "
//                        + "MySQL server using TCP/IP...");
//            String i = request.getParameter("id");
//            id    = new Integer(i).intValue();
//           
//            PreparedStatement ps = con.prepareStatement("select tekst from htmlside where id = ?");
//            ps.setInt(1, id);
//           
//            ResultSet res = ps.executeQuery();
//            String tekst = "";
//            while(res.next()) {
//            tekst = res.getString("tekst");   
//            }
//           
//            HttpSession ses = request.getSession();
//           
//            ses.setAttribute("tekst", tekst);
//            ses.setAttribute("radioButtonId", id + "");
//           
//
//        } catch (Exception e) {
//            System.err.println("Exception: " + e.getMessage());
//        } finally {
//            try {
//                if (con != null)
//                    con.close();
//            } catch (SQLException e) {
//            }
//           
//            String s = request.getParameter("indsend");
//            String s2 = request.getParameter("pis");
//            System.out.println(s);
//            System.out.println(s2);
//           
//            System.out.println("group =" + request.getParameter("c"));
//           
//           
//           
//            response.sendRedirect("controller.jsp");   
    //    }

    }

    /**
    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
    *      response)
    */
    @Override
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
       
       
       
       
       
       
        //denne kode henter data fra hmtlside tabellen
        if(request.getParameter("hent data").equals("hent data")){
        System.out.println("kommer her");
            Connection con = null;
        int id;
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            con = DriverManager.getConnection("jdbc:mysql:///flex", "root",
                    "vlot9024");

            if (!con.isClosed())
                System.out.println("Successfully connected to "
                        + "MySQL server using TCP/IP...");
            String i = request.getParameter("group");
            id    = new Integer(i).intValue();
           
            PreparedStatement ps = con.prepareStatement("select title,overskrift,tekst from htmlside where id = ?");
            ps.setInt(1, id);
           
            ResultSet res = ps.executeQuery();
            String title ="";
            String overskrift ="";
            String tekst = "";
            while(res.next()) {
            title = res.getString("title");
            overskrift = res.getString("overskrift");
            tekst = res.getString("tekst");   
            }
           
            HttpSession ses = request.getSession();
           
            ses.setAttribute("tekst", tekst);
            ses.setAttribute("title", title);
            ses.setAttribute("overskrift", overskrift);
            ses.setAttribute("radioButtonId", id + "");
           

        } catch (Exception e) {
            System.err.println("Exception: " + e.getMessage());
        } finally {
            try {
                if (con != null)
                    con.close();
            } catch (SQLException e) {
            }
        }//end hent data
            if(request.getParameter("indsend") != null) {
            System.out.println(request.getParameter("indsend"));
            }
           
           
           
            response.sendRedirect("controller.jsp");   
        }

    }

}
linie 143

linie 143 er:

if(request.getParameter("indsend") != null) {

Det lyder mystisk at den skulle give NPE - request skulle aldrig være null.

nu har jeg lavet 2 forms, den form der skal opdatere data, men det sker ikke kan du se fejlen arne

package servlets;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
* Servlet implementation class UpdateDataServlet
*/
public class UpdateDataServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
    * @see HttpServlet#HttpServlet()
    */
    public UpdateDataServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
    *      response)
    */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

    /**
    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
    *      response)
    */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // <jsp:useBean id="title" class="java.lang.String" scope="session"/>
        // <jsp:useBean id="overskrift" class="java.lang.String"
        // scope="session"/>
        // <jsp:useBean id="tekst" class="java.lang.String" scope="session"/>
        HttpSession ses = request.getSession();
        String title = (String) ses.getAttribute("title");
        String overskrift = (String) ses.getAttribute("overskrift");
        String tekst = (String) ses.getAttribute("tekst");
        String radioButtonId = (String) ses.getAttribute("radioButtonId");

        System.out.println(title);
        System.out.println(overskrift);
        System.out.println(tekst);
        System.out.println(radioButtonId);
       
        Connection con = null;
       
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            con = DriverManager.getConnection("jdbc:mysql:///flex", "root",
                    "vlotds");

            if (!con.isClosed())
                System.out.println("Successfully connected to "
                        + "MySQL server using TCP/IP...");
           
           
            int id = new Integer(radioButtonId).intValue();
            PreparedStatement ps = con
                    .prepareStatement("update htmlside set title=?,overskrift=?,tekst=? where id =?");
            ps.setString(1, title);
            ps.setString(2, overskrift);
            ps.setString(3, tekst);
            ps.setInt(4, new Integer(radioButtonId).intValue());

            ps.executeUpdate();
           

        } catch (Exception e) {
            System.err.println("Exception: " + e.getMessage());
        } finally {
            try {
                if (con != null)
                    con.close();
            } catch (SQLException e) {
            }
            response.sendRedirect("controller.jsp");
        }
    }

}

problem solved men hvis du vil have point smid et svar

jkl