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JSP two pages

Ivan Bisevac

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posted 14 years ago

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I have to write to pages in JSP to show to professor that i know to search some database (for example northwind from access) and to click on 1 record and then opens second JSP page for selected record and from that page to show report for that selected record (for example for one customer). I am new to JSP but not to servlets and could you help me with this?

Bear Bibeault

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All the work should be done in Java classes, not JSP. JSP should only be used to show the final results.

In other words, if you find yourself starting to put java code into a JSP, you are doing it wrong.

So get your Java classes written to perform all the database and other stuff, and then let us know what problems you are having showing results in the JSPs.

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Ivan Bisevac

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Bear Bibeault wrote:All the work should be done in Java classes, not JSP. JSP should only be used to show the final results.

In other words, if you find yourself starting to put java code into a JSP, you are doing it wrong.

So get your Java classes written to perform all the database and other stuff, and then let us know what problems you are having showing results in the JSPs.

Yout mean that i have to write servlet class? And after that to write jsp? I worked with servlets but with jsp never. Can you explain me more..

Bear Bibeault

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Read this article.

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Ivan Bisevac

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I found example on http://www.roseindia.net/servlets/search.shtml and did some changes and now it is not working. Here is the code:

Search.java

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.sql.*;
import java.sql.*;
import java.util.*;

public class Search extends HttpServlet{ 
 
   public void doPost(HttpServletRequest request, HttpServletResponse response)    throws ServletException,IOException{
            response.setContentType("text/html");
            PrintWriter out = response.getWriter();

System.out.println("MySQL Connect Example.");
            Connection conn = null;
            String url = "jdbc:odbc:northwind";

String driver = "sun.jdbc.odbc.Driver";
            Statement st;
            
            try {
                Class.forName(driver).newInstance();
                conn = DriverManager.getConnection(url);
                System.out.println("Connected to the database");

//sledece parametre koje nam prosledjuje jsp stranica treba da izmenimo u stranici search.jsp
                String  ContactName  = request.getParameter("ContactName");
                String  City  = request.getParameter("City");

//al se stavlja da je null zato sto zelimo samo da napravimo referencu tipa ArrayList
                ArrayList al=null;
                ArrayList emp_list =new ArrayList();
                String query = "select * from customers where ContactName like '"+ContactName+"*' or City='"+City+"'";
                System.out.println("query " + query);
                st = conn.createStatement();
                ResultSet  rs = st.executeQuery(query);

while(rs.next())
                {
                    al  = new ArrayList();
                
                  al.add(rs.getString(1));
                  al.add(rs.getString(2));
                  al.add(rs.getString(3));
                  al.add(rs.getString(4));
                  al.add(rs.getString(5));
                  al.add(rs.getString(6));
                  al.add(rs.getString(7));
                  al.add(rs.getString(8));
                  al.add(rs.getString(10));
                  al.add(rs.getString(11));    
                  System.out.println("al :: "+al);
                  emp_list.add(al);
                }

request.setAttribute("empList",emp_list);
                
             System.out.println("empList " + emp_list);

//   out.println("emp_list " + emp_list);

String nextJSP = "/viewSearch.jsp";
                RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(nextJSP);
                dispatcher.forward(request,response);
                conn.close();
                System.out.println("Disconnected from database");
            } catch (Exception e) {
            e.printStackTrace();
            }
  }
}

<%@ page import="java.util.*" %> 
<html>
<head>
</head>
<body>

<table width="700px" align="center" style="border:1px solid #000000;">
<tr>
<td colspan=8 align="center" style="background-color:ffeeff">Employee Record</td>
</tr>
<tr style="background-color:efefef;">
<td>Customer ID</td>
<td>Company Name</td>
<td>Contact Name</td>
<td>Contact Title</td>
<td>Address</td>
<td>City</td>
<td>Region</td>
<td>Postal Code</td>
<td>Coutry</td>
<td>Phone</td>
<td>Fax</td>
</tr>
<%
int count=0;
String color = "#F9EBB3";

if(request.getAttribute("empList")!=null)
{
 ArrayList al = (ArrayList)request.getAttribute("empList");
 Iterator itr = al.iterator();
 
 
 while(itr.hasNext())
 {
 
 if((count%2)==0)
 {
 
 color = "#eeffee";
 
 
 }
 else
 {
 color = "#F9EBB3";
 }
 count++;
 ArrayList empList = (ArrayList)itr.next();
 %>
<tr style="background-color:<%=color%>;">
<td><%=empList.get(0)%></td>
<td><%=empList.get(1)%></td>
<td><%=empList.get(3)%></td>
<td><%=empList.get(4)%></td>
<td><%=empList.get(5)%></td>
<td><%=empList.get(6)%></td>
<td><%=empList.get(7)%></td>
<td><%=empList.get(8)%></td>
<td><%=empList.get(9)%></td>
<td><%=empList.get(10)%></td>
<td><%=empList.get(11)%></td>

</tr>
 <%
 
 }
}

<%
if(count==0)
{
 %>
<tr>
<td colspan=8 align="center" style="background-color:eeffee">No Record</td>

</tr>
 <%
}
%>
</table>
</body>
</html>

what is doing command al.add(). Maybe this example is for searching and presenting just 1 record from database?

Bear Bibeault

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Ugh! Java code in a JSP? In 2010?

I'd suggest using more up-to-date examples.

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Ivan Bisevac

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Bear Bibeault wrote:Ugh! Java code in a JSP? In 2010?

I am beginner in jsp and don't know why you say this.

Can you give me those examples or links to them. I just need search form and when search is complete to display results on second page. Then from second page to generate report. Can you give me those examples?

Hussein Baghdadi

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Did you read the article Mr.Bear gave to you?
It should give a clear idea what he is trying to tell you.

Bear Bibeault

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Ivan Bisevac wrote:I am beginner in jsp and don't know why you say this.

As a beginner, it's important to not learn bad practices to begin with. Putting Java code in a JSP has been a discredited practice for over 8 years.

You want to avoid reference that use Java scriptlets. Modern JSP uses JSTL (JSP Standard Tag Library) and the EL (Expression Language).

You might also benefit from reading these articles: The Secret Life of JSPs and The Front Man (again).

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Ivan Bisevac

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Ok, i will read this articles tomorow. Is there any book for this with examples?

Bear Bibeault

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Any modern JSP book will cover JSTL and EL.

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Ivan Bisevac

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Ok, i read book Core servlets and jsp pages and now am familiar with jsp. But now i have some questions.
After i get data from database do i put it in html table or there is a data grid in JSP? How to open one record in another page? For example i write sql query that gives me all employees with starting letter 'B' in name. I get some data and display it. How to make that customer make choice of just one employee and after employee is selected how to display result in another page? I don't need code just some advices. Thanks..

Bear Bibeault

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Ivan Bisevac wrote:After i get data from database do i put it in html table or there is a data grid in JSP?

JSP is just a templating technology that helps you create the HTML pages. Any "data grid" will need to be rendered in HTML, JavaScript and CSS. There are 3rd party tag libraries that can help you do this (though I'm not personally impressed by any of them).

How to open one record in another page?

Based on what? A mouse click? If so, get the primary key from the clicked element and submit a request that goes through the whole process of fetching the data and displaying it.

The articles I referenced show this cycle.

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Ivan Bisevac

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Bear Bibeault wrote:

Ivan Bisevac wrote:After i get data from database do i put it in html table or there is a data grid in JSP?

JSP is just a templating technology that helps you create the HTML pages. Any "data grid" will need to be rendered in HTML, JavaScript and CSS. There are 3rd party tag libraries that can help you do this (though I'm not personally impressed by any of them).

How to open one record in another page?

Based on what? A mouse click? If so, get the primary key from the clicked element and submit a request that goes through the whole process of fetching the data and displaying it.

The articles I referenced show this cycle.

Witch 3rd party library are those? Where i could find some info for that..

Bear Bibeault

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I'd try google.

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Ivan Bisevac

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Bear Bibeault wrote:I'd try google.

I found some libraries but i asked for your experience. that's why i am here on forum.

Bear Bibeault

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I've already said that I'm not impressed with any of them, so there isn't one I'd recommend.

I just do it myself. Creating an HTML table in JSP isn't at all hard, and I use jQuery on the client side to instrument the table with the appropriate behaviors.

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