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Hello..I m trying to run the following code which will store the session of a book selected on click of the button.But first it was showing NullPointerException and then blank page..Please Help me in this.. This is the JSP Page
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<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Book Catalog1</title>
</head>
<body>
<form action="/Books/addtocart" target="add">
<!-- <input type="checkbox" name="book1cat" value="JSP" />JSP
<input type="checkbox" name="book1cat" value="C" />C
<input type="checkbox" name="book1cat" value="Java" />Java
<input type="checkbox" name="book1cat" value="Servlet" />Servlet<br/>-->
<b>Jsp</b><input type="submit" value="Add JSP To Cart" name="ADD" /><br/>
<b>Java</b><input type="submit" value="Add Java To Cart" name="ADDJSp" /><br/>
</form>
</body>
</html>
This is the servlet page where i m storing the value(this code is for selecting the first book only):
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class addtocart extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
HttpSession hs=request.getSession(true);
if(hs.isNew()){
hs.setAttribute("ADD", new int[] {0});
}
int[] ADD=(int[])hs.getAttribute("ADD");
try {
if((String)request.getParameter("ADD")!=null){
ADD[0]++;
out.print("Brought a JSP book.You now have "+ADD[0]+ "JSP book");
}
out.print("<HTML><HEAD><TITLE>Shopping Cart</TITLE></HEAD><BODY>");
out.print("<HR><A HREF='/Books/Book1.jsp'>Go to Main</a>");
} finally {
out.close();
}
}
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