Help fowarding data to a jsp page

Question

I know your not meant to double post but i was told it would be better if i post this message in here so:
I am trying to create a bean that will connect to a database and bring back data depending on what a user typed into a html form. However i need some help, if the database does not find any data i want to send a message saying something like "no results" to a jsp page which then be displayed, if results are found i then want to pass on these results to another jsp page.
My question is how would i pass on this data / message to a jsp page? Also if more then one piece of data is returned from the database how would i be able to make sure everything is sent to the jsp?

Answer 1

In the above code a Servlet, a JavaBean, JDBC and everything else is combined into just one class. That is not how it is.
A Servlet is a Servlet --- it is not a JavaBean ---- So create a dedicated class that is purely a Servlet and does what a Servlet is supposed to do. Taking the tutorial on Servlets will help you understand them better.
A JavaBean is a JavaBean ---- it is not a Servlet --- Create a JavaBean class.
Move the Database Connection code to the Data Access Layer --- this means create separate classes that are meant to only access data.
It is better to learn each individual concept before attempting something more complex.
Also build small code into your class, ---- understand what it's doing then compile it frequently.
I'll give you hints on how you should properly implement an MVC pattern.
JSP Page
This page contains an HTML form , with form fields and a submit button.
In the action attribute of the form you will specify the URL-pattern for the Servlet.
The URL-pattern for the servlet will be defined in web.xml , for example
<form action="/MyFirstServlet" method="post" >
</form>Then create a Servlet , in its package , so for example
com.myapp.servlet.MyFirstServlet.java
Place the servlet file in a proper folder structure in the Java source folder.
When the Servlet it compiled it needs to go under the corresponding folder structure under your applications /WEB-INF/classes/ folder.
Your servlet will look something like this:
package com.myapp.servlet.MyFirstServlet;
//All import statements go here
public class MyFirstServlet extends HttpServlet{
   public void doGet(HttpServletRequest request, HttpServletResponse response) throws ......... exceptions {
        doPost(request, response);
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ......... exceptions {
        //Process the request here
request.getAttribute("someFormField");
//similarly get all form fields
//Store all fields into a JavaBean
//Then call a method that saves the data to database
saveToDatabase(pass the javabean here);
private void saveToDatabase(SomeJavaBean someJavaBean){
    //Over here call a DataAccessObject -- DAO that saves the data
   // to the database.
/WEB-INF/web.xml
When you write a servlet you need to define it in web.xml and define a URL mapping also for it in web.xml
JavaBean example
com.myapp.beans.Person.java
package com.myapp.beans.Person;
//whatever import statements (if any) go here
public class Person{
private int age;
private String firstName;
public Person(){} //Every JavaBean must have a default constructor
//Write the Getters and Setters for the private fields above.
//in proper JavaBeans notation as follows
public void setAge(int age){
  this.age = age;
public int getAge(){
   return this.age;
//Similarly write getter and setter for firstName
}You would then use the above JavaBean to transport data between the database layer and JSP layer via the Servlet.
If you are Saving to the Database , you read the HTML form's data and save it into one JavaBean and then pass the JavaBean to the database layer to be saved. In the Database layer you write JDBC code to save the data.
If you are Reading from the database, you create an ArrayList of JavaBean objects in the database layer using JDBC code and then pass the ArrayList to the Servlet which stores it in the Request, then the servlet forwards control to the JSP which then reads the data from the request.
Most of the above is pseudo code, it is just there to give you an idea about how do this properly in MVC --- you can then read tutorials on each of the above --- for example tutorial on Servlet, tutorial on JDBC, tutorial on Java Classes and then understand them more.