Spring MVC 入门
Written by ideawu Posted on 2006-08-26
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./xml/ns/j2ee" 4 xmlns:xsi="http://www./2001/XMLSchema-instance" 5 xsi:schemaLocation="http://java./xml/ns/j2ee 6 http://java./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./jsp/jstl/core</taglib-uri> 53 <taglib-location>/WEB-INF/tld/c.tld</taglib-location> 54 </taglib> 55 <taglib> 56 <taglib-uri>http://java./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:
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./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:
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./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:
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www./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):
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./jsp/jstl/core" %> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www./TR/xhtml1/DTD/xhtml1-transitional.dtd"> 4 <html xmlns="http://www./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> 你可以下载整个 Web 应用程序. 在 Debian Linux, Tomcat 5.5.16, JDK1.5.0 下运行良好. 解压后得到一个 spring 文件夹, 放到你的 webapps 目录下, 在浏览器中输入 http://localhost:8080/spring/hello.do 就可以访问了. |
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