package com.artisan.learnmvc.model;
import java.io.Serializable;
public class Product implements Serializable {
    private static final long serialVersionUID = 748392348L;
    private String name;
    private String description;
    private float price;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    public float getPrice() {
        return price;
    }
    public void setPrice(float price) {
        this.price = price;
    }
}

package com.artisan.learnmvc.form;
public class ProductForm {
    private String name;
    private String description;
    private String price;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    public String getPrice() {
        return price;
    }
    public void setPrice(String price) {
        this.price = price;
    }

package com.artisan.learnmvc.servlet;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.artisan.learnmvc.form.ProductForm;
import com.artisan.learnmvc.model.Product;
/**
 * 
 * @author Mr.Yang
 * @Desc ControllerServlet类继承自javax.servlet.http.HttpServlet. 
 *       其中doGet和doPOST方法都最终调用自定义的process方法，该方法是整个Servlet控制器的核心。
 *
 */
public class ControllerServlet extends HttpServlet {
    private static final long serialVersionUID = 1579L;
    @Override
    public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
            throws IOException, ServletException {
        process(request, response);
    }
    @Override
    public void doPost(HttpServletRequest request,
                       HttpServletResponse response)
            throws IOException, ServletException {
        process(request, response);
    }
    private void process(HttpServletRequest request,
                         HttpServletResponse response)
            throws IOException, ServletException {
        String uri = request.getRequestURI();
        /*
         * uri is in this form: /contextName/resourceName, 
         * for example: /chapter02a/product_input. 
         * However, in the event of a default context, the 
         * context name is empty, and uri has this form
         * /resourceName, e.g.: /product_input
         */
        int lastIndex = uri.lastIndexOf("/");
        String action = uri.substring(lastIndex + 1);
        // execute an action
        if (action.equals("product_input.action")) {
            // no action class, there is nothing to be done
        } else if (action.equals("product_save.action")) {
            // create form
            ProductForm productForm = new ProductForm();
            // populate action properties
            productForm.setName(request.getParameter("name"));
            productForm.setDescription(
                    request.getParameter("description"));
            productForm.setPrice(request.getParameter("price"));
            // create model
            Product product = new Product();
            product.setName(productForm.getName());
            product.setDescription(productForm.getDescription());
            try {
                product.setPrice(Float.parseFloat(
                        productForm.getPrice()));
            } catch (NumberFormatException e) {
            }
            // code to save product
            // store model in a scope variable for the view
            request.setAttribute("product", product);
        }
        // forward to a view
        String dispatchUrl = null;
        if (action.equals("product_input.action")) {
            dispatchUrl = "/WEB-INF/jsp/ProductForm.jsp";
        } else if (action.equals("product_save.action")) {
            dispatchUrl = "/WEB-INF/jsp/ProductDetails.jsp";
        }
        if (dispatchUrl != null) {
            RequestDispatcher rd =
                    request.getRequestDispatcher(dispatchUrl);
            rd.forward(request, response);
        }
    }
}

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    version="3.0"> 
     <servlet>
        <servlet-name>ControllerServlet</servlet-name>
        <servlet-class>com.artisan.learnmvc.servlet.ControllerServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ControllerServlet</servlet-name>
        <url-pattern>*.action</url-pattern>
    </servlet-mapping>
</web-app>

<!DOCTYPE HTML>
<html>
<head>
<title>Add Product Form</title>
<style type="text/css">@import url(css/main.css);</style>
</head>
<body>
<div id="global">
<form action="product_save.action" method="post">
    <fieldset>
        <legend>Add a product</legend>
            <p>
                <label for="name">Product Name: </label>
                <input type="text" id="name" name="name" 
                    tabindex="1">
            </p>
            <p>
                <label for="description">Description: </label>
                <input type="text" id="description" 
                    name="description" tabindex="2">
            </p>
            <p>
                <label for="price">Price: </label>
                <input type="text" id="price" name="price" 
                    tabindex="3">
            </p>
            <p id="buttons">
                <input id="reset" type="reset" tabindex="4">
                <input id="submit" type="submit" tabindex="5" 
                    value="Add Product">
            </p>
    </fieldset>
</form>
</div>
</body>
</html>

<!DOCTYPE HTML>
<html>
<head>
<title>Save Product</title>
<style type="text/css">@import url(css/main.css);</style>
</head>
<body>
<div id="global">
    <h4>The product has been saved.</h4>
    <p>
        <h5>Details:</h5>
        Product Name: ${product.name}<br/>
        Description: ${product.description}<br/>
        Price: ${product.price}
    </p>
</div>
</body>
</html>