springMVC

这篇文章将教你快速地上手使用 Spring 框架. 如果你手上有一本《Spring in Action》, 那么你最好从第三部分"Spring 在 Web 层的应用--建立 Web 层"开始看, 否则那将是一场恶梦!

首先, 我需要在你心里建立起 Spring MVC 的基本概念. 基于 Spring 的 Web 应用程序接收到 http://localhost:8080/hello.do(事实上请求路径是 /hello.do) 的请求后, Spring 将这个请求交给一个名为 helloController 的程序进行处理, helloController 再调用 一个名为 hello.jsp 的 jsp 文件生成 HTML 代码发给用户的浏览器显示. 上面的名称(/hello.do, helloController, hello.jsp) 都是变量, 你可以更改.

在 Spring MVC 中, jsp 文件中尽量不要有 Java 代码, 只有 HTML 代码和"迭代(forEach)"与"判断(if)"两个jstl标签. jsp 文件只作为渲染(或称为视图 View)模板使用.

好了, 我们开始吧. 首先我们需要一个放在 WEB-INF 目录下的 web.xml 文件:

web.xml:
 1 <?xml version="1.0" encoding="UTF-8"?>  2   3 <web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"  4          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  5          xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee  6          http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">  7   8     <context-param>  9         <param-name>contextConfigLocation</param-name> 10         <param-value> 11             /WEB-INF/database.xml 12             /WEB-INF/applicationContext.xml 13         </param-value> 14     </context-param> 15  16     <listener> 17         <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> 18     </listener> 19  20     <filter> 21         <filter-name>encodingFilter</filter-name> 22         <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> 23         <init-param> 24             <param-name>encoding</param-name> 25             <param-value>UTF-8</param-value> 26         </init-param> 27     </filter> 28  29     <filter-mapping> 30         <filter-name>encodingFilter</filter-name> 31         <url-pattern>*.do</url-pattern> 32     </filter-mapping> 33  34     <servlet> 35         <servlet-name>ideawu</servlet-name> 36         <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> 37         <load-on-startup>1</load-on-startup> 38     </servlet> 39  40     <servlet-mapping> 41         <servlet-name>ideawu</servlet-name> 42         <url-pattern>*.do</url-pattern> 43     </servlet-mapping> 44  45     <welcome-file-list> 46         <welcome-file>index.jsp</welcome-file> 47         <welcome-file>index.html</welcome-file> 48     </welcome-file-list> 49  50     <jsp-config> 51         <taglib> 52             <taglib-uri>http://java.sun.com/jsp/jstl/core</taglib-uri> 53             <taglib-location>/WEB-INF/tld/c.tld</taglib-location> 54         </taglib> 55         <taglib> 56             <taglib-uri>http://java.sun.com/jsp/jstl/fmt</taglib-uri> 57             <taglib-location>/WEB-INF/tld/fmt.tld</taglib-location> 58         </taglib> 59     </jsp-config> 60  61 </web-app> 

它配置了以下功能:

  • 配置 DispatcherServlet (servlet 标签), 它是一个 Java Servlet 程序. 我们将它命名为 ideawu. 然后我们再配置 Servlet 映射(servlet-mapping 标签), 也就是你希望哪些请求被DispatcherServlet处理. 这里, 我们设置后缀名为 do(*.do) 的所有URL请求都被名为 ideawu 的 DispatcherServlet 的程序处理. 选择 .do 只是一个习惯,但是你不要选择 .html! 虽然《Spring in Action》选择了 .html, 但是那是一种非常糟糕的作法, 特别是你整合 Apache 和 Tomcat 的时候.

  • 配置 CharacterEncodingFilter (filter 标签), 否则你会发现中文乱码. 因为我的 jsp 和 html 文件都是 UTF-8 编码的, 所以我在 param-value 标签中设置了 UTF-8. 估计你使用的是 GB2312 或者 GBK, 立即转到 UTF-8 上来吧.

  • 分解配置文件. context-param 标签指明我们的配置文件还有 /WEB-INF/database.xml 和 /WEB-INF/applicationContext.xml. ContextLoaderListener(listener 标签) 由此得知配置文件是哪些, 它会将它们载入.

因为我们将 DispatcherServlet 命名为 ideawu, 所以我们在 WEB-INF 目录下建立一个名为 ideawu-servlet.xml 的文件:

ideawu-servlet.xml:
 1 <?xml version="1.0" encoding="UTF-8" ?>  2 <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">  3   4 <beans>  5   6     <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">  7         <property name="prefix" value="/WEB-INF/jsp/" />  8         <property name="suffix" value=".jsp" />  9     </bean> 10  11     <bean id="simpleUrlHandlerMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> 12         <property name="mappings"> 13             <props> 14                 <prop key="/hello.do">helloController</prop> 15             </props> 16         </property> 17     </bean> 18  19     <bean id="helloController" class="com.ideawu.HelloController"> 20         <!-- 21         <property name="helloManager" ref="helloManager" /> 22         --> 23     </bean> 24  25 </beans> 

它配置了以下功能:

  • 配置 InternalResourceViewResolver, 它是 jsp 渲染模板的处理器. 如果你告诉 InternalResourceViewResolver 处理一个名为 hello 的模板时, 它会渲染 /WEB-INF/jsp/hello.jsp 文件. 把 jsp 文件放到 /WEB-INF/jsp/ 目录下是被鼓励的, 这样可以防止用户不经过 Controller 直接访问 jsp 文件从而出错(有些顽皮的人很喜欢这样做).

  • 配置 SimpleUrlHandlerMapping, 在上面的配置文件中, /hello.do 的请求将被 helloController 处理. "/hello.do"和"helloController" 是变量, 你可以更改. 但是你注意到了吗, hello.do 以 .do 作为后缀名. 如果这里(本文的条件下)你不使用.do 作为后缀名, 就没有程序来处理这个请求了. 因为 DispatcherServlet 将收到的请求转交给 SimpleUrlHandlerMapping, DispatcherServlet 收不到的请求, SimpleUrlHandlerMapping 当然也收不到了. 你可以在 props 标签内配置多个 prop 标签.

  • 我们将在后面编写 com.ideawu.HelloController 类.

上面, 我们在 web.xml 文件中告诉 ContextLoaderListener, 我们还有另外两个配置文件 /WEB-INF/database.xml 和 /WEB-INF/applicationContext.xml.

applicationContext.xml:
 1 <?xml version="1.0" encoding="UTF-8"?>  2 <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">  3   4 <beans>  5   6     <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">  7         <property name="locations">  8             <list>  9                 <value>/WEB-INF/jdbc.properties</value> 10             </list> 11         </property> 12     </bean> 13  14 </beans> 

它配置了以下功能:

  • 读取 /WEB-INF/jdbc.properties 文件. 你可以在 list 标签中配置多个 value 标签.

database.xml:
 1 <?xml version="1.0" encoding="UTF-8"?>  2 <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">  3   4 <beans>  5   6     <!-- Remove this if your database setting is fine.  7     <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">  8         <property name="driverClassName" value="${jdbc.driverClassName}"/>  9         <property name="url" value="${jdbc.url}"/> 10         <property name="username" value="${jdbc.username}"/> 11         <property name="password" value="${jdbc.password}"/> 12     </bean> 13     --> 14  15     <!-- Transaction manager for a single JDBC DataSource 16     <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> 17         <property name="dataSource" ref="dataSource"/> 18     </bean> 19     --> 20  21     <!-- 22     <bean id="attributeManager" class="com.ideawu.core.AttributeManager"> 23         <property name="dataSource" ref="dataSource"/> 24     </bean> 25     --> 26  27 </beans> 

它配置了以下功能(不过,已经注释掉了):

  • 配置数据库连接. 类似${jbbc.url}是一种访问变量的方法. 我们可以从 /WEB-INF/jdbc.properties 中找到这个变量的值. 如果你的数据库已经配置好, 就将第一个注释去掉.

jdbc.properties:
1 jdbc.driverClassName=com.mysql.jdbc.Driver 2 jdbc.url=jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=UTF-8 3 jdbc.username=test 4 jdbc.password=12345 
现在, 我们来编写 Java 代码吧.
 1 /***********************************************************  2 * Date: 2006-8-26  3 * File: HelloController.java  4 * Author: ideawu  5 ***********************************************************/  6   7 package com.ideawu;  8   9 import org.springframework.web.servlet.mvc.Controller; 10 import org.springframework.web.servlet.ModelAndView; 11  12 import javax.servlet.http.HttpServletRequest; 13 import javax.servlet.http.HttpServletResponse; 14  15 /** 16  * @author ideawu 17  * 18  */ 19 public class HelloController implements Controller { 20 /*   21     private HelloManager helloManager; 22  23     public void setHelloManager(HelloManager helloManager) { 24         this.helloManager = helloManager; 25     } 26 */ 27  28     public ModelAndView handleRequest(HttpServletRequest request, 29             HttpServletResponse response)throws Exception{ 30  31         request.setAttribute("hello_1", "你好啊, Spring!"); 32         request.setAttribute("hello_2", "Hello World!"); 33  34         return new ModelAndView("hello"); 35     } 36  37 } 

return new ModelAndView("hello"); 告诉 InternalResourceViewResolver jsp 模板的名字叫作 hello. request.setAttribute() 设置的对象我们可以在 jsp 文件中使用.

hello.jsp:
 1 <%@ page contentType="text/html; charset=UTF-8" %>  2 <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>  3 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">  4 <html xmlns="http://www.w3.org/1999/xhtml">  5 <head>  6     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />  7     <title>Hello World!</title>  8 </head>  9 <body> 10  11 <h2>${hello_1}</h2> 12  13 <h2>${hello_2}</h2> 14  15 </body> 16 </html> 

web.xml:

1   <? xml version = " 1.0 "  encoding = " UTF-8 " ?>
 
2  
 
3   < web - app version = " 2.4 "  xmlns = " http://java.sun.com/xml/ns/j2ee "
 
4           xmlns:xsi = " http://www.w3.org/2001/XMLSchema-instance "
 
5           xsi:schemaLocation = " http://java.sun.com/xml/ns/j2ee
 6          http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd
" >
 
7  
 
8       < context - param >
 
9           < param - name > contextConfigLocation </ param - name >
10           < param - value >
11               / WEB - INF / database.xml
12               / WEB - INF / applicationContext.xml
13           </ param - value >
14       </ context - param >
15  
16       < listener >
17           < listener - class > org.springframework.web.context.ContextLoaderListener </ listener - class >
18       </ listener >
19  
20       < filter >
21           < filter - name > encodingFilter </ filter - name >
22           < filter - class > org.springframework.web.filter.CharacterEncodingFilter </ filter - class >
23           < init - param >
24               < param - name > encoding </ param - name >
25               < param - value > UTF - 8 </ param - value >
26           </ init - param >
27       </ filter >
28  
29       < filter - mapping >
30           < filter - name > encodingFilter </ filter - name >
31           < url - pattern >* . do </ url - pattern >
32       </ filter - mapping >
33  
34       < servlet >
35           < servlet - name > ideawu </ servlet - name >
36           < servlet - class > org.springframework.web.servlet.DispatcherServlet </ servlet - class >
37           < load - on - startup > 1 </ load - on - startup >
38       </ servlet >
39  
40       < servlet - mapping >
41           < servlet - name > ideawu </ servlet - name >
42           < url - pattern >* . do </ url - pattern >
43       </ servlet - mapping >
44  
45       < welcome - file - list >
46           < welcome - file > index.jsp </ welcome - file >
47           < welcome - file > index.html </ welcome - file >
48       </ welcome - file - list >
49  
50       < jsp - config >
51           < taglib >
52               < taglib - uri > http: // java.sun.com/jsp/jstl/core</taglib-uri>
53               < taglib - location >/ WEB - INF / tld / c.tld </ taglib - location >
54           </ taglib >
55           < taglib >
56               < taglib - uri > http: // java.sun.com/jsp/jstl/fmt</taglib-uri>
57               < taglib - location >/ WEB - INF / tld / fmt.tld </ taglib - location >
58           </ taglib >
59       </ jsp - config >
60  
61   </ web - app >

1   <? xml version = " 1.0 "  encoding = " UTF-8 "   ?>
 
2   <! DOCTYPE beans PUBLIC  " -//SPRING//DTD BEAN//EN "   " http://www.springframework.org/dtd/spring-beans.dtd " >
 
3  
 
4   < beans >
 
5  
 
6       < bean id = " viewResolver "  class = " org.springframework.web.servlet.view.InternalResourceViewResolver " >
 
7           < property name = " prefix "  value = " /WEB-INF/jsp/ "   />
 
8           < property name = " suffix "  value = " .jsp "   />
 
9       </ bean >
10  
11       < bean id = " simpleUrlHandlerMapping "  class = " org.springframework.web.servlet.handler.SimpleUrlHandlerMapping " >
12           < property name = " mappings " >
13               < props >
14                   < prop key = " /hello.do " > helloController </ prop >
15               </ props >
16           </ property >
17       </ bean >
18  
19       < bean id = " helloController "  class = " com.ideawu.HelloController " >
20           <!--
21           < property name = " helloManager "  ref = " helloManager "   />
22           -->
23       </ bean >
24  
25   </ beans >

ideawu
- servlet.xml:
 
1   <? xml version = " 1.0 "  encoding = " UTF-8 " ?>
 
2   <! DOCTYPE beans PUBLIC  " -//SPRING//DTD BEAN//EN "   " http://www.springframework.org/dtd/spring-beans.dtd " >
 
3  
 
4   < beans >
 
5  
 
6       < bean id = " propertyConfigurer "  class = " org.springframework.beans.factory.config.PropertyPlaceholderConfigurer " >
 
7           < property name = " locations " >
 
8               < list >
 
9                   < value >/ WEB - INF / jdbc.properties </ value >
10               </ list >
11           </ property >
12       </ bean >
13  
14   </ beans >

applicationContext.xml:
 
1   <? xml version = " 1.0 "  encoding = " UTF-8 " ?>
 
2   <! DOCTYPE beans PUBLIC  " -//SPRING//DTD BEAN//EN "   " http://www.springframework.org/dtd/spring-beans.dtd " >
 
3  
 
4   < beans >
 
5  
 
6       < bean id = " propertyConfigurer "  class = " org.springframework.beans.factory.config.PropertyPlaceholderConfigurer " >
 
7           < property name = " locations " >
 
8               < list >
 
9                   < value >/ WEB - INF / jdbc.properties </ value >
10               </ list >
11           </ property >
12       </ bean >
13  
14   </ beans >

database.xml:
 
1   <? xml version = " 1.0 "  encoding = " UTF-8 " ?>
 
2   <! DOCTYPE beans PUBLIC  " -//SPRING//DTD BEAN//EN "   " http://www.springframework.org/dtd/spring-beans.dtd " >
 
3  
 
4   < beans >
 
5  
 
6       <!--  Remove  this   if  your database setting is fine.
 
7       < bean id = " dataSource "  class = " org.apache.commons.dbcp.BasicDataSource "  destroy - method = " close " >
 
8           < property name = " driverClassName "  value = " ${jdbc.driverClassName} " />
 
9           < property name = " url "  value = " ${jdbc.url} " />
10           < property name = " username "  value = " ${jdbc.username} " />
11           < property name = " password "  value = " ${jdbc.password} " />
12       </ bean >
13       -->
14  
15       <!--  Transaction manager  for  a single JDBC DataSource
16       < bean id = " transactionManager "  class = " org.springframework.jdbc.datasource.DataSourceTransactionManager " >
17           < property name = " dataSource "  ref = " dataSource " />
18       </ bean >
19       -->
20  
21       <!--
22       < bean id = " attributeManager "  class = " com.ideawu.core.AttributeManager " >
23           < property name = " dataSource "  ref = " dataSource " />
24       </ bean >
25       -->
26  
27   </ beans >

你可能感兴趣的:(springMVC)