From index.jsp code,
statement.executeQuery("select * from fus where tester_num like 'hf60' ") ;
Example I want "hf60" to be a variable(userinput), wherein USER must input/write data from input text then submit and get the data so that the result will be
("select * from fus where tester_num like 'userinput' ")
Where should I insert that code, Is it in InsertServlet .java or in Index.jsp.? or make another filename.java code? Please help. Thanks;)
Index.jsp
<%# page import="java.sql.*" %>
<% Class.forName("oracle.jdbc.driver.OracleDriver"); %>
<HTML>
<HEAD>
<TITLE>SHIFT REPORT </TITLE>
</HEAD>
<BODY BGCOLOR=##342D7E>
<CENTER>
<H2><FONT COLOR="#ECD672" FACE="Verdana" >SHIFT REPORT</FONT></H2></CENTER>
<hr>
<%
Connection connection=DriverManager.getConnection ("jdbc:oracle:thin:#oradev2.*****.com:1521:RPADB","shift_admin", //
"shift_admin"
);
Statement statement = connection.createStatement() ;
//**Should I input the codes here?**
ResultSet resultset =
statement.executeQuery("select * from fus where tester_num like 'hf60") ;
%>
<TABLE BORDER="1" BGCOLOR="CCFFFF" width='200%' cellspacing='1' cellpadding='0' bordercolor="black" border='1'>
<TR>
<TH bgcolor='#DAA520'> <font size='2'>RECORD NUMBER</TH>
<TH bgcolor='#DAA520'><font size='2'>TESTER NUMBER</TH>
<TH bgcolor='#DAA520'><font size='2'>DATE</TH>
<TH bgcolor='#DAA520'><font size='2'>TIME</TH>
<TH bgcolor='#DAA520'><font size='2'>SYSTEM TYPE</TH>
<TH bgcolor='#DAA520'><font size='2'>PACKAGE</TH>
<TH bgcolor='#DAA520'><font size='2'>SOCKETS</TH>
<TH bgcolor='#DAA520'><font size='2'>VALIDATED BY</TH>
</TR>
<% while(resultset.next()){ %>
<TR>
<TD> <font size='2'><center><%= resultset.getLong(1) %></center></TD>
<TD> <font size='2'><center><%= resultset.getString(2) %></center></TD>
<TD> <font size='2'><center><%= resultset.getDate(3) %></center></TD>
<TD> <font size='2'><center><%= resultset.getString(4) %></center></TD>
<TD> <font size='2'><center><%= resultset.getString(5) %></center></TD>
<TD> <font size='2'><center><%= resultset.getString(6) %></center></TD>
<TD> <font size='2'><center><%= resultset.getString(7) %></center></TD>
<TD> <font size='2'><center><%= resultset.getString(8) %></center></TD>
</TR>
<% } %>
</TABLE>
</BODY>
</HTML>
InsertServlet.java
package fusion.shift.servlets.db;
import java.sql.*;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class InsertServlet extends HttpServlet {
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
public void destroy() {
}
public boolean processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
String rec_num = request.getParameter("rec_num");
String tester_num = request.getParameter("tester_num");
String t_date = request.getParameter("t_date");
String t_time = request.getParameter("t_time");
String sys_type = request.getParameter("sys_type");
String packages = request.getParameter("package");
String sockets = request.getParameter("sockets");
String sockets = request.getParameter("val");
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
PreparedStatement ps = null;
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
con=DriverManager.getConnection("jdbc:oracle:thin:#oradev2.*****.com:1521:RPADB","shift_admin", //
"shift_admin"
);
String sql;
sql = "INSERT INTO fusion_shiftrpt(RECORD_NUM, TESTER_NUM, T_DATE, T_TIME, SYSTEM_TYPE, PACKAGE, SOCKETS,VAL) VALUES (?,?,?,?,?,?,?,?)";
ps = con.prepareStatement(sql);
stmt = con.createStatement();
ps.setString(1, rec_num);
.0+ ps.setString(2, tester_num);
ps.setString(3, t_date);
ps.setString(4, t_time);
ps.setString(5, sys_type);
ps.setString(6, packages);
ps.setString(7, sockets);
ps.setString(8, val);
ps.executeUpdate();
} catch (SQLException e) {
throw new ServletException(e);
} catch (ClassNotFoundException e) {
throw new ServletException(e);
} finally {
try {
if(rs != null)
rs.close();
if(stmt != null)
stmt.close();
if(ps != null)
ps.close();
if(con != null)
con.close();
} catch (SQLException e) {}
}
return(true);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request,response);
//String url = request.getRequestURI();
//System.out.println(url);
}
}
If you insist on staying with this design, I would suggest that you use JSTL. This provides a set of tags for accessing data, controlling logic, and performing SQL access.
See the Sun Tutorial on the Standard Tag Library and the SQL tags. This is a much better approach than embedding scriptlets into your JSP. That said, I would recommend this approach (or scriplets) only be used for prototypes or as a very-temporary fix.
With JSTL, you could replace all of the scriptlets with something similar to:
<sql:query var="rows" >
select * from fus where tester_num like ?
<sql:param value="${param.user_input}" />
</sql:query>
<table>
<c:forEach var="row" items="${rows}">
<tr>
<td>${row.column1name}</td>
<td>${row.column2name}</td>
<td>${row.column3name}</td>
</tr>
</c:forEach>
</table>
You have access to the request in a JSP. So if your JSP were to be accessed like this:
test.jsp?q=userinput
You could get to it like this in the JSP:
request.getParameter('userinput');
You should convert your JSP code to at least use a preparedStatement when you do this:
PreparedStatement ps = connection.prepareStatement("select * from fus where tester_num like ?");
ps.setString(1, "%" + request.getParameter('userinput') + "%");
ResultSet resultSet = ps.executeQuery();
As tvanfosson said, you should remove all database access code from your view logic (JSP). You should just show the info in your JSP, let the Servlet do all the processing. I also strongly recommend you to use an OMR framework like Hibernate.
Related
I attempted to retrieve user information from the MySQL database, but when I ran my program and searched for the user by name, nothing appeared in the HTML table. I can't figure out what's the issue. Below in my code,
Web Service Code
#WebMethod(operationName = "search")
public List<UserRegister> search(#WebParam(name = "name")String name ) {
Connection connection = DBUtils.getConnection();
List<UserRegister> user = new ArrayList<>();
UserRegister u=null;
try {
String searchQuery = "select * from register where name= ?";
PreparedStatement ps = connection.prepareStatement(searchQuery);
ps.setString(1, name);
ResultSet rs = ps.executeQuery();
while (rs.next()) {
u = new UserRegister();
u.setName(rs.getString("name"));
u.setBranch(rs.getString("branch"));
u.setAge(rs.getString("age"));
u.setPhone(rs.getString("phone"));
user.add(u);
}
}catch(SQLException asd){
System.out.println(asd.getMessage());
}
return user;
}
Java Servlet
#WebServlet("/SearchServlet")
public class SearchServlet extends HttpServlet {
#Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String Name = request.getParameter("name");
UserRegister userRegister = new UserRegister();
userRegister.setName(Name);
searchClass sclass = new searchClass();
request.setAttribute("name", sclass.search(Name));
RequestDispatcher view = request.getRequestDispatcher("display.jsp");
view.forward(request, response);
}
}
Java Class For Call the Web Service
public class searchClass {
public List<UserRegister> search( String username) {
SerachService_Service service=new SerachService_Service();
SerachService proxy =service.getSerachServicePort();
return (List<UserRegister>) proxy.search(username);
}
}
JSp For Search Bar
<form method="Get" action="SearchServlet">
<table border="0" width="300" align="center" bgcolor="#CDFFFF">
<tr><td colspan=2 align="center">
<h3>Search Employee</h3></td></tr>
<tr><td ><b>User Name</b></td>
<td>: <input type="text" name="name">
<tr><td colspan=2 align="center">
<input type="submit"></td></tr>
</table>
</form>
</body>
JSP Display Data
<table>
<c:forEach var="user" items="${name}">
<tr>
<td>
<c:out value="${user.name}" />
</td>
<td>
<c:out value="${user.branch}" />
</td>
<td>
<c:out value="${user.age}" />
</td>
<td>
<c:out value="${user.phone}" />
</td>
</tr>
</c:forEach>
</body>
I have already coded the servlet and the dao part of the delete method.
Once i want to use the method in jsp page, it returned ERROR 500 / ERROR 404.
I am using tomcat 7,Java 7 and windows 10. Running oracle. I tried to use ajax to link the servlet delete method but it still didn't work.
// deleteStaffServelt
public class DeleteStaffServlet extends HttpServlet {
enter code here
/**
*
*/
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String ids = request.getParameter("userId");
int deleteId = Integer.parseInt(ids);
StaffDao staffDao = new StaffDao();
staffDao.delete(deleteId);
response.sendRedirect("deleteStaffServlet?id=" + deleteId);
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
// delete method in Dao
public void delete(int id) {
try {
String sql = "delete from ZZZ_EMPLOYEES where ZE_ID = " + id;
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(1, id);
ps.executeUpdate();
ps.close();
} catch (Exception ex) {
ex.printStackTrace();
}
// jsp
<body>
<form action="listServletTwo">
<table border="0" cellspacing="0">
<tr>
<td>社員No. <input name="noStart" type="text" size="8" />
～ <input name="noEnd" type="text" size="8" /> <input
type="submit" value="検索" />
</td>
<td>社員名. <input name="name" type="text" size="20" /> <input
type="submit" value="検索" />
</td>
</tr>
</table>
</br>
<%
List<Staff> list1 = (List<Staff>) session.getAttribute("list");
if (list1 != null) {
%>
<table border="1" cellspacing="0">
<tr bgcolor="pink">
<td>社員No.</td>
<td>ユーザーID</td>
<td>社員名</td>
<td>削除機能</td>
<td>更新機能</td>
</tr>
<%
for (Staff s : list1) {
%>
<tr>
<td id="<%=s.getId()%>"><%=s.getId()%></td>
<td><%=s.getNo()%></td>
<td><%=s.getName()%></td>
<td>Delete</td>
<td>名前:<input name="name" type="text" size="10" /> ユーザーID:<input
name="name" type="text" size="10" />
<input type="submit" value="Edit" name="edit" onclick="editRecord(<%=s.getId()%>);">
</td>
</tr>
<%
}
}
session.removeAttribute("list");
%>
</table>
</form>
result is HTTP Status 500 – Internal Server Error
java.lang.NumberFormatException: null
Here ,Delete,you have used id=<%=s.getId()%> i.e : you are getting value <%=s.getId()%> in parameter id but in your servlet ,you are getting parameter using request.getParameter("userId"); just change this to request.getParameter("id");.
Also, your delete query is wrong it should like below :
// delete method in Dao
public void delete(int id) {
try {
//you have to give placeholder(?) in query not the value
String sql = "delete from ZZZ_EMPLOYEES where ZE_ID =?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(1, id);
ps.executeUpdate();
ps.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
I am not sure what you are doing here :
response.sendRedirect("deleteStaffServlet?id=" + deleteId);
But, I think you have already deleted required row from table ,so there is no need to do that again. So, just change that to below :
response.sendRedirect("yourjsppage");
I am having trouble trying to insert data into a table in my database in netbeans, below is my code:
public class NewUser extends HttpServlet {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code>
* methods.
*
* #param request servlet request
* #param response servlet response
* #throws ServletException if a servlet-specific error occurs
* #throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
HttpSession session = request.getSession(false);
String [] query = new String[5];
query[0] = (String)request.getParameter("username");
query[1] = (String)request.getParameter("password");
query[2] = (String)request.getParameter("confPassword");
query[3] = (String)request.getParameter("name");
query[4] = (String)request.getParameter("address");
Jdbc jdbc = (Jdbc)session.getAttribute("dbbean");
if (jdbc == null)
request.getRequestDispatcher("/WEB-INF/conErr.jsp").forward(request, response);
else {
jdbc.insert(query);
request.setAttribute("message", query[0]+" has been registered successfully!");
}
This is in a class "NewUser.java". The insert method is in a class "jdbc" and is as follows:
public void insert(String[] str){
PreparedStatement ps = null;
try {
ps = connection.prepareStatement("INSERT INTO CUSTOMER VALUES (?,?,?,?)",PreparedStatement.RETURN_GENERATED_KEYS);
ps.setString(1, str[0].trim());
ps.setString(2, str[1]);
ps.setString(3, str[3]);
ps.setString(4, str[4]);
ps.executeUpdate();
ps.close();
System.out.println("1 row added.");
} catch (SQLException ex) {
Logger.getLogger(Jdbc.class.getName()).log(Level.SEVERE, null, ex);
}
}
The "CUSTOMER" table looks as follows:
# | Username | Password | Name | Address | ID
('ID' is the primary key which is auto incremented)
The JSP where the user inputs the information is as follows:
<%#page import="model.Jdbc"%>
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>User</title>
</head>
<body>
<h2>User's details:</h2>
<%! int i = 0;
String str = "Register";
String url = "NewUser.do";
%>
<%
if ((String) request.getAttribute("msg") == "del") {
str = "Delete";
url = "Delete.do";
}
else
{
str = "Register";
url = "NewUser.do";
}
%>
<form method="POST" action="<%=url%>">
<table>
<tr>
<th></th>
<th>Please provide your following details</th>
</tr>
<tr>
<td>Username:</td>
<td><input type="text" name="username"/></td>
</tr>
<tr>
<td>Password:</td>
<td><input type="password" name="password"/></td>
</tr>
<tr>
<td>Confirm Password:</td>
<td><input type="password" name="confPassword"/></td>
</tr>
<tr>
<td>Name:</td>
<td><input type="text" name="name"/></td>
</tr>
<tr>
<td>Address:</td>
<td><input type="text" name="address"/></td>
</tr>
<tr>
<td> <input type="submit" value="<%=str%>"/></td>
</tr>
</table>
</form>
<%
if (i++ > 0 && request.getAttribute("message") != null) {
out.println(request.getAttribute("message"));
i--;
}
%>
</br>
<jsp:include page="foot.jsp"/>
</body>
</html>
The SQL statement used to create the database:
CREATE TABLE Customer (
username varchar(20),
password varchar(20),
name varchar(20),
address varchar(60),
id INT primary key GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1)
);
The code doesn't throw any errors however, when I check the database to see if the data has been added it never gets added and I cannot figure out why (I think it's something to do with the "insert" method?). I have looked around for solutions however, I still get the same outcome and could really use some help.
Cheers,
For Oracle you need to specify column for auto generated columns:
ps = connection.prepareStatement("INSERT INTO CUSTOMER VALUES (?,?,?,?)", new String[]{"ID"})
For ID column
You forgot to replace prepareStatement.return.. to Statement.return..ps = connection.prepareStatement("INSERT INTO CUSTOMER VALUES (?,?,?,?)",Statement.RETURN_GENERATED_KEYS,new String[]{"ID"});
The history:
History I.
History II.
So the problem is still here. If I select somebody and press the delete button, not to delete from database else a new empty record created.
The client.java:
public class client implements DatabaseConnection{
private static Connection conn = null;
private static void createConnection(){
try {
conn = DriverManager.getConnection(URL, USER, PASSWORD);
} catch (SQLException ex) {
Logger.getLogger(client.class.getName()).log(Level.SEVERE, null, ex);
}
}
private static void closeConnection(){
if (conn != null){
try {
conn.close();
} catch (SQLException ex) {
Logger.getLogger(client.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
public List clientList(){
createConnection();
List list=new ArrayList();
try {
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery("SELECT * FROM customer");
while(rs.next()){
**list.add(rs.getString("ID"));**
list.add(rs.getString("CNAME"));
list.add(rs.getString("ADDRESS"));
list.add(rs.getString("PHONENUMBER"));
}
stmt.close();
} catch (Exception e) {
e.printStackTrace(System.err);
}
return list;
}
public void newClient(String name, String address, String phoneNumber)
throws SQLException{
PreparedStatement ps = null;
try {
createConnection();
String insert="INSERT INTO CUSTOMER(CNAME,ADDRESS, PHONENUMBER)
VALUES(?,?,?)";
ps=conn.prepareStatement(insert);
ps.setString(1, name);
ps.setString(2, address);
ps.setString(3, phoneNumber);
ps.executeUpdate();
ps.close();
} catch (Exception e) {
e.printStackTrace(System.err);
}
finally {
ps.close();
closeConnection();
}
}
public void deleteClient(String ID){
try {
createConnection();
String delete="DELETE FROM CUSTOMER WHERE ID=?";
PreparedStatement ps=conn.prepareStatement(delete);
ps.setString(1, ID);
ps.executeUpdate();
} catch (Exception e) {
e.printStackTrace(System.err);
}
**finally {
closeConnection();
}**
}
}
The index.jsp:
<jsp:useBean id="client" class="database.client" scope="page" />
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body bgcolor="lightgrey">
<%
String ID=request.getParameter("ID");
String NAME=request.getParameter("CNAME");
String ADDRESS=request.getParameter("ADDRESS");
String PHONENUMBER=request.getParameter("PHONENUMBER");
%>
<form method="post" action="">
<table border="0" align="left">
<th colspan="2" align="center" style="color: brown">Field</th>
<tr>
<td>Name:</td>
<td><input type="text" name="CNAME" style="background-
color:beige"/></td>
</tr>
<tr>
<td>Address?</td>
<td><input type="text" name="ADDRESS" style="background-
color:beige"/></td>
</tr>
<tr>
<td>PhoneNumber:</td>
<td><input type="text" name="PHONENUMBER" style="background-
color:beige"/></td>
</tr>
<input type="submit" name="OK" onclick="
<%
if(NAME!=null && ADDRESS!=null && PHONENUMBER!=null){
client.newClient(NAME, ADDRESS, PHONENUMBER);
}
%>" value="OK"/>
<input type="submit" name="Cancel" onclick="
<%
//nothing
%>" value="Cancel"/>
<input type="submit" name="Delete" onclick="
<%client.deleteClient(ID);%>" value="Delete"/>
</table>
<table border="2">
<th colspan="4" align="center" bgcolor="orange">Clients</th>
<tr bgcolor="silver" align="center">
<td> </td>
**<td>ID</td>**
<td>Name</td>
<td>Address</td>
<td>PhoneNumber</td>
</tr>
<%
List list=client.clientList();
Iterator it=list.iterator();
while(it.hasNext()){
out.print("<tr bgcolor='lightgreen'>");
out.print("<td>");
**ID**=(String)it.next();
out.print("<input type='radio' name='ID' value="+**ID**+"/>");
out.print("</td>");
out.print("<td>");
out.print(**ID**);
out.print("</td>");
for (int i = 0; i < **3**; i++) {
out.print("<td>");
out.print(it.next());
out.print("</td>");
}
out.print("</tr>");
}
%>
</table>
</form>
</body>
</html>
Just create a new Servlet (Delete Servlet) and pass the ID in url and handle it in new jsp page ...You can change your code likethis :
Index JSP:
Delete
Delete Servlet : Updated
#WebServlet(name = "DeleteServlet", urlPatterns = {"/DeleteServlet"})
public class DeleteServlet extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
private static final Logger LOGGER = Logger.getLogger(CurdOperationsImpl.class.getName());
#Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String ID = request.getParameter("id");
int id = Integer.parseInt(PersonId);
deleteClient(id); // add your own code
out.println("<h2 style='color: green'>Person Deleted Sucessfully.</h2>");
response.sendRedirect("index.jsp");
}else {
}
}
Bonus : get this my ugly Servlet-JSP-Mysql project is ready to use Github link
I hope this help you.
I have a JSP page in which I have two tags. In first I am trying get input such as Car Maker name such as Tata, Hyundai, Toyota, Audi etc. When user selects any option in first , it should display car models from that maker such as Innova,Land Cruiser etc. So when user selects any option in first tag, I am calling a servlet which gets all the models from database in a list and setting the list as attribute of session and forwarding the request back to JSP. But in jsp when I try to fetch the list it is giving NULL POINTER EXCEPTION. How to solve it?
The code is as below:
DbReviewCar.java
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
Connection conn= null;
PreparedStatement pstmt= null;
ResultSet rs;
String sql= null;
String maker= request.getParameter("make");
List modellist= new ArrayList();
/*if(maker==null)
{
modellist.add("ferrari");
modellist.add("hummer");
request.getSession().setAttribute("value", modellist);
request.getRequestDispatcher("CarReview.jsp").forward(request,response);
}
else
{*/
try {
Class.forName("com.mysql.jdbc.Driver");
conn= DriverManager.getConnection("jdbc:mysql://localhost/cardetails", "root", "Welcome123");
sql= "select model from cars where make=?;";
pstmt= conn.prepareStatement(sql);
pstmt.setString(1, maker);
rs= pstmt.executeQuery();
while(rs.next())
{
String mod= rs.getString(1);
modellist.add(mod);
System.out.println(mod+">>>>>>>>>>>>>>>>>>.");
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
request.getSession().setAttribute("value", modellist);
request.getRequestDispatcher("CarReview.jsp").forward(request,response);
}
CarReview.jsp
Here is my JSP file
<form action="DbReviewCar" method="get" name="myform">
<table>
<tr>
<td>
<tr>
<td>Make:</td>
<td><select name="make" onchange="this.form.submit()"><option>select</option>
<option>Maruti</option>
<option>Ford</option>
<option>Honda</option>
<option>Skoda</option>
<option>Tata</option>
<option>Audi</option>
<option>Toyota</option></select><br></br></td>
</tr>
<%
List list = new ArrayList();
list.addAll((List) (request.getSession().getAttribute("value")));
%>
<tr>
<td>Model:</td>
<td><select name="model">
<%
for (int i = 0; i < list.size(); i++) {
%>
<option value=<%=list.get(i)%>><%=list.get(i)%></option>
<%
}
%>
</select><br></br></td>
</tr>
<tr>
<td>Rating For Style:</td>
<td><input type="text" name="style"><br></br></td>
</tr>
<tr>
<td>Rating for comfort:</td>
<td><input type="text" name="comfort"><br></br></td>
</tr>
<tr>
<td>Rating for Performance:</td>
<td><input type="text" name="performance"><br></br></td>
</tr>
<tr>
<td>Rating for FuelEconomy:</td>
<td><input type="text" name="economy"><br></br></td>
</tr>
<tr>
<td>Review:</td>
<td><textarea cols="18" rows="3"></textarea><br></br></td>
</tr>
<tr>
<td><Button>Save</Button></td>
<td><input type="reset" name="cancel" value="Cancel" /></td>
</tr>
</table>
</form>
When jsp loading for the first time the "value" atribute is not set.
Try to check null for value:
request.getSession().getAttribute("value")