3.SpringMVC介绍

1.采用Spring MVC的好处

Dispathcher Servlet必须做如下的事情：

1.根据URI调用相应的action

2.实例化正确的控制器类

3.根据请求参数值来构造表单bean

3.调用控制器对象的相应方法

4.转向到一个视图（JSP页面）

SpringMVC提供了Dispatcher Servlet

使用基于XML的配置文件，实例化控制器

自动绑定用户输入，正确转换数据类型

可以校验用户输入，支持国际化和本地化，

支持多种视图

2.SpringMVC的DispatcherServlet

相当于调度员Servlet

配置部署：

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app version="3.0" 
 3         xmlns="http://java.sun.com/xml/ns/javaee"
 4         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 5         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
 6     <servlet>
 7         <servlet-name>springmvc</servlet-name>
 8         <servlet-class>
 9             org.springframework.web.servlet.DispatcherServlet
10         </servlet-class>
11         <load-on-startup>1</load-on-startup>
12     </servlet>
13 
14     <servlet-mapping>
15         <servlet-name>springmvc</servlet-name>
16         <url-pattern> /</url-pattern>
17     </servlet-mapping>
18     
19 </web-app>

load-on-startup 如存在，在程序启动时加载，
如不存在，在一个请求时候加载

springMVC的配置文件，可以放在WEB-INF下
也可以放在任何地方，用init-param加载该文件

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app version="3.0" 
 3         xmlns="http://java.sun.com/xml/ns/javaee"
 4         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 5         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
 6     <servlet>
 7         <servlet-name>springmvc</servlet-name>
 8         <servlet-class>
 9             org.springframework.web.servlet.DispatcherServlet
10         </servlet-class>
11         <init-param>
12             <param-name>contextConfigLocation</param-name>
13             <param-value>/WEB-INF/config/springmvc-config.xml</param-value>
14         </init-param>
15         <load-on-startup>1</load-on-startup>    
16     </servlet>
17 
18     <servlet-mapping>
19         <servlet-name>springmvc</servlet-name>
20         <url-pattern>*.action</url-pattern>
21     </servlet-mapping>
22 </web-app>


3.Controller接口(传统风格控制器，要实现Controller接口)
2.5以前开发控制的唯一方法是org.springframework.web.servlet.mvc.Controller接口
只有一个方法handleRequest，而他的实现类只能处理一个单一动作Action
 1 ModelAndView handleRequest(HttpServletRequest request,HttpServletResponse response) 
而基于注解的控制器可以控制多个动作，无需实现任何接口



4.SpringMVC第一个应用
1.目录结构
spring-webmvc-x.y.z.jar包括了 DispatcherServlet

2.部署描述符文件和SpringMVC配置文件

2.1 部署文件

没有init-param，所以放在WEB-INF下

<url-pattern>/</url-pattern> 将所有的URL映射到该Servlet上

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app version="3.0" 
 3         xmlns="http://java.sun.com/xml/ns/javaee"
 4         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 5         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
 6     <servlet>
 7         <servlet-name>springmvc</servlet-name>
 8         <servlet-class>
 9             org.springframework.web.servlet.DispatcherServlet
10         </servlet-class>
11         <load-on-startup>1</load-on-startup>
12     </servlet>
13 
14     <servlet-mapping>
15         <servlet-name>springmvc</servlet-name>
16         <url-pattern>/</url-pattern>
17     </servlet-mapping>
18     
19 </web-app>

2.2 SpringMVC的配置文件

2个控制器类

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4        xsi:schemaLocation="http://www.springframework.org/schema/beans
 5        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
 6        
 7     <bean name="/product_input.action" class="app03a.controller.InputProductController"/>
 8     <bean name="/product_save.action" class="app03a.controller.SaveProductController"/>
 9 
10 </beans>

3.Controller

 1 package app03a.controller;
 2 
 3 import javax.servlet.http.HttpServletRequest;
 4 import javax.servlet.http.HttpServletResponse;
 5 
 6 import org.apache.commons.logging.Log;
 7 import org.apache.commons.logging.LogFactory;
 8 import org.springframework.web.servlet.ModelAndView;
 9 import org.springframework.web.servlet.mvc.Controller;
10 
11 public class InputProductController implements Controller {
12 
13     private static final Log logger = LogFactory
14             .getLog(InputProductController.class);
15 
16     @Override
17     public ModelAndView handleRequest(HttpServletRequest request,
18             HttpServletResponse response) throws Exception {
19         logger.info("InputProductController called");
20         return new ModelAndView("/WEB-INF/jsp/ProductForm.jsp");
21     }
22 
23 }

 1 package app03a.controller;
 2 
 3 import javax.servlet.http.HttpServletRequest;
 4 import javax.servlet.http.HttpServletResponse;
 5 
 6 import org.apache.commons.logging.Log;
 7 import org.apache.commons.logging.LogFactory;
 8 import org.springframework.web.servlet.ModelAndView;
 9 import org.springframework.web.servlet.mvc.Controller;
10 
11 import app03a.domain.Product;
12 import app03a.form.ProductForm;
13 
14 public class SaveProductController implements Controller {
15 
16     private static final Log logger = LogFactory
17             .getLog(SaveProductController.class);
18 
19     @Override
20     public ModelAndView handleRequest(HttpServletRequest request,
21             HttpServletResponse response) throws Exception {
22         logger.info("SaveProductController called");
23         ProductForm productForm = new ProductForm();
24         // populate action properties
25         productForm.setName(request.getParameter("name"));
26         productForm.setDescription(request.getParameter("description"));
27         productForm.setPrice(request.getParameter("price"));
28 
29         // create model
30         Product product = new Product();
31         product.setName(productForm.getName());
32         product.setDescription(productForm.getDescription());
33         try {
34             product.setPrice(Float.parseFloat(productForm.getPrice()));
35         } catch (NumberFormatException e) {
36         }
37 
38         // insert code to save Product
39 
40         return new ModelAndView("/WEB-INF/jsp/ProductDetails.jsp", "product",
41                 product);//路径，模型名称，模型
42     }
43 
44 }

 1 package app03a.form;
 2 
 3 public class ProductForm {
 4     private String name;
 5     private String description;
 6     private String price;
 7 
 8     public String getName() {
 9         return name;
10     }
11     public void setName(String name) {
12         this.name = name;
13     }
14     public String getDescription() {
15         return description;
16     }
17     public void setDescription(String description) {
18         this.description = description;
19     }
20     public String getPrice() {
21         return price;
22     }
23     public void setPrice(String price) {
24         this.price = price;
25     }
26 }

 1 package app03a.domain;
 2 import java.io.Serializable;
 3 
 4 public class Product implements Serializable {
 5     private static final long serialVersionUID = 748392348L;
 6     private String name;
 7     private String description;
 8     private float price;
 9 
10     public String getName() {
11         return name;
12     }
13     public void setName(String name) {
14         this.name = name;
15     }
16     public String getDescription() {
17         return description;
18     }
19     public void setDescription(String description) {
20         this.description = description;
21     }
22     public float getPrice() {
23         return price;
24     }
25     public void setPrice(float price) {
26         this.price = price;
27     }
28 }

4.View

ProductForm.jsp

 1 <!DOCTYPE HTML>
 2 <html>
 3 <head>
 4 <title>Add Product Form</title>
 5 <style type="text/css">@import url(css/main.css);</style>
 6 </head>
 7 <body>
 8 
 9 <div id="global">
10 <form action="product_save.action" method="post">
11     <fieldset>
12         <legend>Add a product</legend>
13             <p>
14                 <label for="name">Product Name: </label>
15                 <input type="text" id="name" name="name" 
16                     tabindex="1">
17             </p>
18             <p>
19                 <label for="description">Description: </label>
20                 <input type="text" id="description" 
21                     name="description" tabindex="2">
22             </p>
23             <p>
24                 <label for="price">Price: </label>
25                 <input type="text" id="price" name="price" 
26                     tabindex="3">
27             </p>
28             <p id="buttons">
29                 <input id="reset" type="reset" tabindex="4">
30                 <input id="submit" type="submit" tabindex="5" 
31                     value="Add Product">
32             </p>
33     </fieldset>
34 </form>
35 </div>
36 </body>
37 </html>

ProductrDetails.jsp

 1 <!DOCTYPE HTML>
 2 <html>
 3 <head>
 4 <title>Save Product</title>
 5 <style type="text/css">@import url(css/main.css);</style>
 6 </head>
 7 <body>
 8 <div id="global">
 9     <h4>The product has been saved.</h4>
10     <p>
11         <h5>Details:</h5>
12         Product Name: ${product.name}<br/>
13         Description: ${product.description}<br/>
14         Price: $${product.price}
15     </p>
16 </div>
17 </body>
18 </html>

5.测试应用

1 http://localhost:8080/app03a/product_input.action

5.View Resolver

View Resolver负责配置视图解析器

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 
 3 <beans xmlns="http://www.springframework.org/schema/beans"
 4        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 5        xsi:schemaLocation="http://www.springframework.org/schema/beans
 6        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
 7 
 8     <bean name="/product_input.action" class="app03b.controller.InputProductController"/>
 9     <bean name="/product_save.action" class="app03b.controller.SaveProductController"/>
10     <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
11         <property name="prefix" value="/WEB-INF/jsp/"/>
12         <property name="suffix" value=".jsp"/>
13     </bean>
14 </beans>

视图解析器配置了前缀和后缀两个属性：

view路径可以缩短，仅需提供myPage，无需在写/WEB-INF/jsp/myPage.jsp