Btukfyl

So basically, when I try submitting my jsp, the control wents to the servlet , but the values of all the control in jsp becomes null

"ViewBook.jsp"

<%@page contentType="text/html" pageEncoding="UTF-8"%>

<%@include file="Header_1.jsp" %>

<form action="<%=request.getContextPath()%>/BookServlet" method="post" 

enctype="multipart/form-data">

<table>    

        <th colspan="2"></th>

        <tr>    

            <td>

                ID:

            </td>

            <td>

                <input type="number" name="id">

            </td>



        </tr>

         <tr>    

            <td>

                Title:

            </td>

            <td>

                <input type="text" name="title">

            </td>

        </tr>

         <tr>    

            <td>

                Author

            </td>

            <td>

                <input type="text" name="author">

            </td>



        </tr>

         <tr>    

            <td>

                Price:

            </td>

            <td>

                <input type="number" name="price">

            </td>



        </tr>

         <tr>    

            <td>

                Book image:

            </td>

            <td>

                <input type="file" name="book_img">

            </td>



        </tr>

         <tr>    

            <td>

                Publish date:

            </td>

            <td>

                <input type="date" name="pub_date">     

            </td>

        </tr>

         <tr>    

            <td>                          

                <input type="submit" value="add" formaction=" 

   <%=request.getContextPath()%>/BookServlet?action=add">

                <input type="submit" value="delete" 

    formaction="G:sem5AJTQ-4srcjavaBookServle?action=delete">

                <input type="submit" value="update" formaction=" 

   <%=request.getContextPath()%>/BookServlet?action=update">

                <input type="submit" value="view" formaction=" 

   <%=request.getContextPath()%>/BookServlet?action=view">

            </td>

        </tr>   

</table>

</form>



<%@include file="Footer.jsp" %>

"BookServlet.java"

@WebServlet (name="BookServlet", urlPatterns = {"/BookServlet"})

public class BookServlet extends HttpServlet {

protected void processRequest(HttpServletRequest request, 

HttpServletResponse response)

        throws ServletException, IOException {

    response.setContentType("text/html;charset=UTF-8");



}



@Override

protected void doGet(HttpServletRequest request, HttpServletResponse 

response)

        throws ServletException, IOException {

      try (PrintWriter out = response.getWriter()) {



    } 

    }  

//    processRequest(request, response);

}



@Override

protected void doPost(HttpServletRequest request, HttpServletResponse 

response)

        throws ServletException, IOException {

     String title=request.getParameter("title");

        String author=request.getParameter("author");

        String price=request.getParameter("price");

        System.out.println("price=="+price);

        String book_img=request.getParameter("book_img");

        System.out.println("book:imagre===="+book_img);

        String pub_date=request.getParameter("pub_date");

        String action=request.getParameter("action");

        SimpleDateFormat sdf=new SimpleDateFormat("mm/dd/yyyy");

        Date d = null;

    try {

        d = (Date) sdf.parse(pub_date);

    } catch (Exception ex) {

        System.out.println("Exception ex="+ex);

    }

    Part filepart=request.getPart("book_img");

    System.out.println("part====="+filepart);

    InputStream is=filepart.getInputStream();

        BookBean bb=new BookBean();

  //      ResultSet rs=bb.ViewAllBooks();

        if(action.equals("add"))

        {

         Book b=new Book(0,title,author,Integer.parseInt(price),d,is);

            bb.add(b);

            HttpSession s=request.getSession(true);

           // s.setAttribute("rs", rs);

            RequestDispatcher 

rd=request.getRequestDispatcher("ViewAllBooks.jsp");

            rd.forward(request, response);

  //  processRequest(request, response);

}else if(action.equals("update"))

        {            Book b=new 

Book(0,title,author,Integer.parseInt(price),d,is);

          //  boolean flag= bb.update(b);

            HttpSession s=request.getSession(true);

      //      s.setAttribute("rs", rs);

            RequestDispatcher 

rd=request.getRequestDispatcher("ViewAllBooks.jsp");

            rd.forward(request, response);

        }else if(action.equals("delete")){}

        else if(action.equals("view")){}



}



@Override

public String getServletInfo() {

    return "Short description";

}// </editor-fold>



}

This is what I got in my catch block
-Exception ex=java.lang.NullPointerException

StackTrace:

 java.lang.NullPointerException

at BookCrud.BookServlet.doPost(BookServlet.java:136)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter

(ApplicationFilterChain.java:231)

at org.apache.catalina.core.ApplicationFilterChain.doFilter

(ApplicationFilterChain.java:166)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter

(ApplicationFilterChain.java:193)

at org.apache.catalina.core.ApplicationFilterChain.doFilter

(ApplicationFilterChain.java:166)

at org.apache.catalina.core.StandardWrapperValve.invoke

(StandardWrapperValve.java:199)

at org.apache.catalina.core.StandardContextValve.invoke

(StandardContextValve.java:96)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke

(AuthenticatorBase.java:491)

at org.apache.catalina.core.StandardHostValve.invoke

(StandardHostValve.java:139)

at 

org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)

at org.apache.catalina.valves.AbstractAccessLogValve.invoke

(AbstractAccessLogValve.java:668)

at 

org.apache.catalina.core.StandardEngineValve.invoke

(StandardEngineValve.java:87)

at org.apache.catalina.connector.CoyoteAdapter.service

(CoyoteAdapter.java:343)

at 

org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)

at org.apache.coyote.AbstractProcessorLight.process

(AbstractProcessorLight.java:66)

at org.apache.coyote.AbstractProtocol$ConnectionHandler.process

(AbstractProtocol.java:764)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun

(NioEndpoint.java:1388)

at 

org.apache.tomcat.util.net.SocketProcessorBase.run

(SocketProcessorBase.java:49)

at java.util.concurrent.ThreadPoolExecutor.runWorker

(ThreadPoolExecutor.java:1149)

at

java.util.concurrent.ThreadPoolExecutor$Worker.run

(ThreadPoolExecutor.java:624)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run

(TaskThread.java:61)

at java.lang.Thread.run(Thread.java:748)

any help from your side
also, I have surfed a lot for this on StackOverflow and other websites but
I didn't get any proper solution for this.......

you can not directly get parameters by using request.getParameter(name);. While using it, form fields aren't available as parameter of the request, they are included in the stream, so you can not get it the normal way.

Refer this: http://commons.apache.org/proper/commons-fileupload//using.html, under the section Processing the uploaded items.

For all those who are facing the same error ::You can use jar files as mentioned by @secret super star ,But if you dont want to do so here is a tip :

Just

import javax.servlet.annotation.MultipartConfig; 

in your servlet and add

@MultipartConfig(maxFileSize = 16177215)    //Length of the file

annotation ,That's it

Note: In my case following will be my servlet

@WebServlet (name="BookServlet", urlPatterns = {"/BookServlet"})

@MultipartConfig(maxFileSize = 16177215)    

public class BookServlet extends HttpServlet {

protected void processRequest(HttpServletRequest request, 

HttpServletResponse response)

    throws ServletException, IOException {

response.setContentType("text/html;charset=UTF-8");



}



@Override

protected void doGet(HttpServletRequest request, HttpServletResponse 

response)

    throws ServletException, IOException {

  try (PrintWriter out = response.getWriter()) {



} 

}  

//    processRequest(request, response);

}



@Override

protected void doPost(HttpServletRequest request, HttpServletResponse 

response)

    throws ServletException, IOException {

 String title=request.getParameter("title");

    String author=request.getParameter("author");

    String price=request.getParameter("price");

    System.out.println("price=="+price);

    String book_img=request.getParameter("book_img");

    System.out.println("book:imagre===="+book_img);

    String pub_date=request.getParameter("pub_date");

    String action=request.getParameter("action");

    SimpleDateFormat sdf=new SimpleDateFormat("mm/dd/yyyy");

    Date d = null;

try {

    d = (Date) sdf.parse(pub_date);

} catch (Exception ex) {

    System.out.println("Exception ex="+ex);

}

Part filepart=request.getPart("book_img");

System.out.println("part====="+filepart);

InputStream is=filepart.getInputStream();

    BookBean bb=new BookBean();

  //      ResultSet rs=bb.ViewAllBooks();

    if(action.equals("add"))

    {

     Book b=new Book(0,title,author,Integer.parseInt(price),d,is);

        bb.add(b);

        HttpSession s=request.getSession(true);

       // s.setAttribute("rs", rs);

        RequestDispatcher 

rd=request.getRequestDispatcher("ViewAllBooks.jsp");

         rd.forward(request, response);

 //  processRequest(request, response);

}else if(action.equals("update"))

    {            Book b=new 

Book(0,title,author,Integer.parseInt(price),d,is);

      //  boolean flag= bb.update(b);

        HttpSession s=request.getSession(true);

  //      s.setAttribute("rs", rs);

        RequestDispatcher 

rd=request.getRequestDispatcher("ViewAllBooks.jsp");

        rd.forward(request, response);

    }else if(action.equals("delete")){}

    else if(action.equals("view")){}



}



@Override

public String getServletInfo() {

return "Short description";

}// </editor-fold>



}