【Java.Web】MVC —— 基于Servlet Controller的Model2 —— 示例

基于Servlet Controller的Model2

示例

这个应用程序可以用来输入产品信息；在如图的表单中输入信息：

http://localhost:8080/base-webapp/product_input

并提交，然后，应用程序给用户发送一个确认页面，并显示所保存产品的详细信息。

http://localhost:8080/base-webapp/product_save

这个应用程序能够执行下面这两个action：

• 显示Add Product表单，URI中包含字符串“product_input”
• 保存产品，并返回确认页面，URI中包含字符串“product_save”

这个应用包含一下组件：

• Product类时模型对象，包含产品信息
• ProductForm类，封装用于输入产品的HTML表单域
• ControllerServlet类，是这个Model2应用的Controller
• Action类，用于保存产品信息
• View的两个JSP页面：ProductForm.jsp和ProductDetails.jsp

源码：

product bean 类：

package com.gof.test.bean;

import java.io.Serializable;

public class Product implements Serializable {

	/**
	 * 
	 */
	private static final long serialVersionUID = -2088880133830936693L;

	private String nameString;
	private String description;
	private float price;
	
	public String getName(){
		return nameString;
	}
	public void setName(String name){
		this.nameString = 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;
	}
}

product form 类：

package com.gof.test.bean;

public class ProductForm {
	private String nameString;
	private String description;
	private String price;
	
	public String getName(){
		return nameString;
	}
	public void setName(String name){
		this.nameString = 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;
	}
}

ControllerServlet类：

package com.gof.test.servlet;

import java.io.IOException;
import java.net.URL;

import javax.print.DocFlavor.STRING;
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.gof.test.action.SaveProductAction;
import com.gof.test.bean.Product;
import com.gof.test.bean.ProductForm;

public class ControllerServlet extends HttpServlet {
	
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException{
		process(req, resp);
	}
	
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException{
		process(req, resp);
	}
	
	private void process(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException{
		String uri = req.getRequestURI();
		int lastIndex = uri.lastIndexOf("/");
		String action = uri.substring(lastIndex + 1);
		String dispatchUrlString = null;
		
		if (action.equals("product_input")){
			dispatchUrlString = "/jsp/controller/ProductForm.jsp";
		}else 
		if (action.equals("product_save")){
			ProductForm productForm = new ProductForm();
			
			productForm.setName(req.getParameter("name"));
			productForm.setDescription(req.getParameter("description"));
			productForm.setPrice(req.getParameter("price"));
			
			Product product = new Product();
			product.setName(productForm.getName());
			product.setDescription(productForm.getDescription());
			try{
				product.setPrice(Float.parseFloat(productForm.getPrice()));
			}catch (NumberFormatException e){
				e.printStackTrace();
			}
			
			SaveProductAction saveProductAction = new SaveProductAction();
			saveProductAction.save(product);
			
			req.setAttribute("product", product);
			dispatchUrlString = "/jsp/controller/ProductDetails.jsp";
		}
        
		if (dispatchUrlString != null){
			RequestDispatcher rDispatcher = req.getRequestDispatcher(dispatchUrlString);
			rDispatcher.forward(req, resp);
		}
	}
}

在web.xml中注册这个servlet：

<!-- Servlet Controller -->
  <servlet>
  	 <servlet-name>controller</servlet-name>
  	 <servlet-class>com.gof.test.servlet.ControllerServlet</servlet-class>
   </servlet>
   <servlet-mapping>
      <servlet-name>controller</servlet-name>
      <url-pattern>/product_input</url-pattern>
   </servlet-mapping>
   <servlet-mapping>
      <servlet-name>controller</servlet-name>
      <url-pattern>/product_save</url-pattern>
   </servlet-mapping>

save action类：

package com.gof.test.action;

import com.gof.test.bean.Product;

public class SaveProductAction {
    public void save(Product product){
    	// insert product into the database
    }
}

View - ProductForm.jsp :

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Add Product Form</title>
</head>
<body>

<div>
    <h3>Add a product</h3>
    <form method="post" action="product_save">
        <table>
            <tr>
                <td>Product Name:</td>
                <td><input type="text" name="name"/></td>
            </tr>
            <tr>
                <td>Description:</td>
                <td><input type="text" name="description"/></td>
            </tr>
            <tr>
                <td>Price:</td>
                <td><input type="text" name="price"/></td>
            </tr>
            <tr>
                <td><input type="reset" /></td>
                <td><input type="submit" value="Add Product"/></td>
            </tr>
        </table>
    </form>
</div>

</body>
</html>

View - ProductDeails.jsp：

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Save Product</title>
</head>
<body>

<div>
    <h4>The product has been saved.</h4>
    <p>
        <h5>Details:</h5>
        Product Name: ${product.name}<br/>
        Description: ${product.description}<br/>
        Price:${product.price}<br/>
    </p>
</div>

</body>
</html>