現在主流的Web MVC框架除了Struts這個主力 外,其次就是Spring MVC了,因此這也是作為一名程序員需要掌握的主流框架,框架選擇多了,應對多變的需求和業務時,可實行的方案自然就多了。不過要想靈活運用Spring MVC來應對大多數的Web開發,就必須要掌握它的配置及原理。
一、Spring MVC環境搭建:(Spring 2.5.6 + Hibernate 3.2.0)
1. jar包引入
Spring 2.5.6:spring.jar、spring-webmvc.jar、commons-logging.jar、cglib-nodep-2.1_3.jar
Hibernate 3.6.8:hibernate3.jar、hibernate-jpa-2.0-api-1.0.1.Final.jar、antlr-2.7.6.jar、commons-collections-3.1、dom4j-1.6.1.jar、javassist-3.12.0.GA.jar、jta-1.1.jar、slf4j-api-1.6.1.jar、slf4j-nop-1.6.4.jar、相應數據庫的驅動jar包
2. web.xml配置(部分)
- <!-- Spring MVC配置 -->
- <!-- ====================================== -->
- <servlet>
- <servlet-name>spring</servlet-name>
- <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
- <!-- 可以自定義servlet.xml配置文件的位置和名稱,默認為WEB-INF目錄下,名稱為[<servlet-name>]-servlet.xml,如spring-servlet.xml
- <init-param>
- <param-name>contextConfigLocation</param-name>
- <param-value>/WEB-INF/spring-servlet.xml</param-value> 默認
- </init-param>
- -->
- <load-on-startup>1</load-on-startup>
- </servlet>
- <servlet-mapping>
- <servlet-name>spring</servlet-name>
- <url-pattern>*.do</url-pattern>
- </servlet-mapping>
- <!-- Spring配置 -->
- <!-- ====================================== -->
- <listener>
- <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
- </listener>
- <!-- 指定Spring Bean的配置文件所在目錄。默認配置在WEB-INF目錄下 -->
- <context-param>
- <param-name>contextConfigLocation</param-name>
- <param-value>classpath:config/applicationContext.xml</param-value>
- </context-param>
<!-- Spring MVC配置 --> <!-- ====================================== --> <servlet> <servlet-name>spring</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!-- 可以自定義servlet.xml配置文件的位置和名稱,默認為WEB-INF目錄下,名稱為[<servlet-name>]-servlet.xml,如spring-servlet.xml <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/spring-servlet.xml</param-value> 默認 </init-param> --> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>spring</servlet-name> <url-pattern>*.do</url-pattern> </servlet-mapping> <!-- Spring配置 --> <!-- ====================================== --> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <!-- 指定Spring Bean的配置文件所在目錄。默認配置在WEB-INF目錄下 --> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:config/applicationContext.xml</param-value> </context-param>
3. spring-servlet.xml配置
spring-servlet這個名字是因為上面web.xml中<servlet-name>標簽配的值為spring(<servlet-name>spring</servlet-name>),再加上“-servlet”后綴而形成的spring-servlet.xml文件名,如果改為springMVC,對應的文件名則為springMVC-servlet.xml。
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
- xmlns:context="http://www.springframework.org/schema/context"
- xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
- http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
- http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
- http://www.springframework.org/schema/context <a href="http://www.springframework.org/schema/context/spring-context-3.0.xsd">http://www.springframework.org/schema/context/spring-context-3.0.xsd</a>">
- <!-- 啟用spring mvc 注解 -->
- <context:annotation-config />
- <!-- 設置使用注解的類所在的jar包 -->
- <context:component-scan base-package="controller"></context:component-scan>
- <!-- 完成請求和注解POJO的映射 -->
- <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
- <!-- 對轉向頁面的路徑解析。prefix:前綴, suffix:后綴 -->
- <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/jsp/" p:suffix=".jsp" />
- </beans>
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/context <a href="http://www.springframework.org/schema/context/spring-context-3.0.xsd">http://www.springframework.org/schema/context/spring-context-3.0.xsd</a>"> <!-- 啟用spring mvc 注解 --> <context:annotation-config /> <!-- 設置使用注解的類所在的jar包 --> <context:component-scan base-package="controller"></context:component-scan> <!-- 完成請求和注解POJO的映射 --> <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" /> <!-- 對轉向頁面的路徑解析。prefix:前綴, suffix:后綴 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/jsp/" p:suffix=".jsp" /> </beans>
4. applicationContext.xml配置
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xmlns:aop="http://www.springframework.org/schema/aop"
- xmlns:tx="http://www.springframework.org/schema/tx"
- xsi:schemaLocation="
- http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
- http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
- http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
- <!-- 采用hibernate.cfg.xml方式配置數據源 -->
- <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
- <property name="configLocation">
- <value>classpath:config/hibernate.cfg.xml</value>
- </property>
- </bean>
- <!-- 將事務與Hibernate關聯 -->
- <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
- <property name="sessionFactory">
- <ref local="sessionFactory"/>
- </property>
- </bean>
- <!-- 事務(注解 )-->
- <tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true"/>
- <!-- 測試Service -->
- <bean id="loginService" class="service.LoginService"></bean>
- <!-- 測試Dao -->
- <bean id="hibernateDao" class="dao.HibernateDao">
- <property name="sessionFactory" ref="sessionFactory"></property>
- </bean>
- </beans>
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"> <!-- 采用hibernate.cfg.xml方式配置數據源 --> <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"> <property name="configLocation"> <value>classpath:config/hibernate.cfg.xml</value> </property> </bean> <!-- 將事務與Hibernate關聯 --> <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager"> <property name="sessionFactory"> <ref local="sessionFactory"/> </property> </bean> <!-- 事務(注解 )--> <tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true"/> <!-- 測試Service --> <bean id="loginService" class="service.LoginService"></bean> <!-- 測試Dao --> <bean id="hibernateDao" class="dao.HibernateDao"> <property name="sessionFactory" ref="sessionFactory"></property> </bean> </beans>
二、詳解
Spring MVC與Struts從原理上很相似(都是基於MVC架構),都有一個控制頁面請求的Servlet,處理完后跳轉頁面。看如下代碼(注解):
以上4個方法示例,是一個Controller里含有不同的請求url,也可以采用一個url訪問,通過url參數來區分訪問不同的方法,代碼如下:
- package controller;
- import javax.servlet.http.HttpServletRequest;
- import org.springframework.stereotype.Controller;
- import org.springframework.web.bind.annotation.RequestMapping;
- import org.springframework.web.bind.annotation.RequestParam;
- import entity.User;
- @Controller //類似Struts的Action
- public class TestController {
- @RequestMapping("test/login.do") // 請求url地址映射,類似Struts的action-mapping
- public String testLogin(@RequestParam(value="username")String username, String password, HttpServletRequest request) {
- // @RequestParam是指請求url地址映射中必須含有的參數(除非屬性required=false)
- // @RequestParam可簡寫為:@RequestParam("username")
- if (!"admin".equals(username) || !"admin".equals(password)) {
- return "loginError"; // 跳轉頁面路徑(默認為轉發),該路徑不需要包含spring-servlet配置文件中配置的前綴和后綴
- }
- return "loginSuccess";
- }
- @RequestMapping("/test/login2.do")
- public ModelAndView testLogin2(String username, String password, int age){
- // request和response不必非要出現在方法中,如果用不上的話可以去掉
- // 參數的名稱是與頁面控件的name相匹配,參數類型會自動被轉換
- if (!"admin".equals(username) || !"admin".equals(password) || age < 5) {
- return new ModelAndView("loginError"); // 手動實例化ModelAndView完成跳轉頁面(轉發),效果等同於上面的方法返回字符串
- }
- return new ModelAndView(new RedirectView("../index.jsp")); // 采用重定向方式跳轉頁面
- // 重定向還有一種簡單寫法
- // return new ModelAndView("redirect:../index.jsp");
- }
- @RequestMapping("/test/login3.do")
- public ModelAndView testLogin3(User user) {
- // 同樣支持參數為表單對象,類似於Struts的ActionForm,User不需要任何配置,直接寫即可
- String username = user.getUsername();
- String password = user.getPassword();
- int age = user.getAge();
- if (!"admin".equals(username) || !"admin".equals(password) || age < 5) {
- return new ModelAndView("loginError");
- }
- return new ModelAndView("loginSuccess");
- }
- @Resource(name = "loginService") // 獲取applicationContext.xml中bean的id為loginService的,並注入
- private LoginService loginService; //等價於spring傳統注入方式寫get和set方法,這樣的好處是簡潔工整,省去了不必要得代碼
- @RequestMapping("/test/login4.do")
- public String testLogin4(User user) {
- if (loginService.login(user) == false) {
- return "loginError";
- }
- return "loginSuccess";
- }
- }
package controller; import javax.servlet.http.HttpServletRequest; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import entity.User; @Controller //類似Struts的Action public class TestController { @RequestMapping("test/login.do") // 請求url地址映射,類似Struts的action-mapping public String testLogin(@RequestParam(value="username")String username, String password, HttpServletRequest request) { // @RequestParam是指請求url地址映射中必須含有的參數(除非屬性required=false) // @RequestParam可簡寫為:@RequestParam("username") if (!"admin".equals(username) || !"admin".equals(password)) { return "loginError"; // 跳轉頁面路徑(默認為轉發),該路徑不需要包含spring-servlet配置文件中配置的前綴和后綴 } return "loginSuccess"; } @RequestMapping("/test/login2.do") public ModelAndView testLogin2(String username, String password, int age){ // request和response不必非要出現在方法中,如果用不上的話可以去掉 // 參數的名稱是與頁面控件的name相匹配,參數類型會自動被轉換 if (!"admin".equals(username) || !"admin".equals(password) || age < 5) { return new ModelAndView("loginError"); // 手動實例化ModelAndView完成跳轉頁面(轉發),效果等同於上面的方法返回字符串 } return new ModelAndView(new RedirectView("../index.jsp")); // 采用重定向方式跳轉頁面 // 重定向還有一種簡單寫法 // return new ModelAndView("redirect:../index.jsp"); } @RequestMapping("/test/login3.do") public ModelAndView testLogin3(User user) { // 同樣支持參數為表單對象,類似於Struts的ActionForm,User不需要任何配置,直接寫即可 String username = user.getUsername(); String password = user.getPassword(); int age = user.getAge(); if (!"admin".equals(username) || !"admin".equals(password) || age < 5) { return new ModelAndView("loginError"); } return new ModelAndView("loginSuccess"); } @Resource(name = "loginService") // 獲取applicationContext.xml中bean的id為loginService的,並注入 private LoginService loginService; //等價於spring傳統注入方式寫get和set方法,這樣的好處是簡潔工整,省去了不必要得代碼 @RequestMapping("/test/login4.do") public String testLogin4(User user) { if (loginService.login(user) == false) { return "loginError"; } return "loginSuccess"; } }
其實RequestMapping在Class上,可看做是父Request請求url,而RequestMapping在方法上的可看做是子Request請求url,父子請求url最終會拼起來與頁面請求url進行匹配,因此RequestMapping也可以這么寫:
查看源碼打印?
- package controller;
- import org.springframework.stereotype.Controller;
- import org.springframework.web.bind.annotation.RequestMapping;
- @Controller
- @RequestMapping("/test3/*") // 父request請求url
- public class TestController3 {
- @RequestMapping("login.do") // 子request請求url,拼接后等價於/test3/login.do
- public String testLogin(String username, String password, int age) {
- if (!"admin".equals(username) || !"admin".equals(password) || age < 5) {
- return "loginError";
- }
- return "loginSuccess";
- }
- }
package controller; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; @Controller @RequestMapping("/test3/*") // 父request請求url public class TestController3 { @RequestMapping("login.do") // 子request請求url,拼接后等價於/test3/login.do public String testLogin(String username, String password, int age) { if (!"admin".equals(username) || !"admin".equals(password) || age < 5) { return "loginError"; } return "loginSuccess"; } }
三、結束語
掌握以上這些Spring MVC就已經有了很好的基礎了,幾乎可應對與任何開發,在熟練掌握這些后,便可更深層次的靈活運用的技術,如多種視圖技術,例如 Jsp、Velocity、Tiles、iText 和 POI。Spring MVC框架並不知道使用的視圖,所以不會強迫您只使用 JSP 技術。