现在主流的Web MVC框架除了Struts这个主力 外,其次就是Spring MVC了,因此这也是作为一名程序员需要掌握的主流框架,框架选择多了,应对多变的需求和业务时,可实行的方案自然就多了。不过要想灵活运用Spring MVC来应对大多数的Web开发,就必须要掌握它的配置及原理。
一、Spring MVC环境搭建:(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、相应数据库的驱动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>
- <!-- 可以自定义servlet.xml配置文件的位置和名称,默认为WEB-INF目录下,名称为[<servlet-name>]-servlet.xml,如spring-servlet.xml
- <init-param>
- <param-name>contextConfigLocation</param-name>
- <param-value>/WEB-INF/spring-servlet.xml</param-value> 默认
- </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的配置文件所在目录。默认配置在WEB-INF目录下 -->
- <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> <!-- 可以自定义servlet.xml配置文件的位置和名称,默认为WEB-INF目录下,名称为[<servlet-name>]-servlet.xml,如spring-servlet.xml <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/spring-servlet.xml</param-value> 默认 </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的配置文件所在目录。默认配置在WEB-INF目录下 --> <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这个名字是因为上面web.xml中<servlet-name>标签配的值为spring(<servlet-name>spring</servlet-name>),再加上“-servlet”后缀而形成的spring-servlet.xml文件名,如果改为springMVC,对应的文件名则为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>">
- <!-- 启用spring mvc 注解 -->
- <context:annotation-config />
- <!-- 设置使用注解的类所在的jar包 -->
- <context:component-scan base-package="controller"></context:component-scan>
- <!-- 完成请求和注解POJO的映射 -->
- <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
- <!-- 对转向页面的路径解析。prefix:前缀, suffix:后缀 -->
- <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>"> <!-- 启用spring mvc 注解 --> <context:annotation-config /> <!-- 设置使用注解的类所在的jar包 --> <context:component-scan base-package="controller"></context:component-scan> <!-- 完成请求和注解POJO的映射 --> <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" /> <!-- 对转向页面的路径解析。prefix:前缀, suffix:后缀 --> <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方式配置数据源 -->
- <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
- <property name="configLocation">
- <value>classpath:config/hibernate.cfg.xml</value>
- </property>
- </bean>
- <!-- 将事务与Hibernate关联 -->
- <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
- <property name="sessionFactory">
- <ref local="sessionFactory"/>
- </property>
- </bean>
- <!-- 事务(注解 )-->
- <tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true"/>
- <!-- 测试Service -->
- <bean id="loginService" class="service.LoginService"></bean>
- <!-- 测试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方式配置数据源 --> <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"> <property name="configLocation"> <value>classpath:config/hibernate.cfg.xml</value> </property> </bean> <!-- 将事务与Hibernate关联 --> <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager"> <property name="sessionFactory"> <ref local="sessionFactory"/> </property> </bean> <!-- 事务(注解 )--> <tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true"/> <!-- 测试Service --> <bean id="loginService" class="service.LoginService"></bean> <!-- 测试Dao --> <bean id="hibernateDao" class="dao.HibernateDao"> <property name="sessionFactory" ref="sessionFactory"></property> </bean> </beans>
二、详解
Spring
MVC与Struts从原理上很相似(都是基于MVC架构),都有一个控制页面请求的Servlet,处理完后跳转页面。看如下代码(注解):
以上4个方法示例,是一个Controller里含有不同的请求url,也可以采用一个url访问,通过url参数来区分访问不同的方法,代码如下:
- 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 //类似Struts的Action
- public class TestController {
- @RequestMapping("test/login.do") // 请求url地址映射,类似Struts的action-mapping
- public String testLogin(@RequestParam(value="username")String username, String password, HttpServletRequest request) {
- // @RequestParam是指请求url地址映射中必须含有的参数(除非属性required=false)
- // @RequestParam可简写为:@RequestParam("username")
- if (!"admin".equals(username) || !"admin".equals(password)) {
- return "loginError"; // 跳转页面路径(默认为转发),该路径不需要包含spring-servlet配置文件中配置的前缀和后缀
- }
- return "loginSuccess";
- }
- @RequestMapping("/test/login2.do")
- public ModelAndView testLogin2(String username, String password, int age){
- // request和response不必非要出现在方法中,如果用不上的话可以去掉
- // 参数的名称是与页面控件的name相匹配,参数类型会自动被转换
- if (!"admin".equals(username) || !"admin".equals(password) || age < 5) {
- return new ModelAndView("loginError"); // 手动实例化ModelAndView完成跳转页面(转发),效果等同于上面的方法返回字符串
- }
- return new ModelAndView(new RedirectView("../index.jsp")); // 采用重定向方式跳转页面
- // 重定向还有一种简单写法
- // return new ModelAndView("redirect:../index.jsp");
- }
- @RequestMapping("/test/login3.do")
- public ModelAndView testLogin3(User user) {
- // 同样支持参数为表单对象,类似于Struts的ActionForm,User不需要任何配置,直接写即可
- 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") // 获取applicationContext.xml中bean的id为loginService的,并注入
- private LoginService loginService; //等价于spring传统注入方式写get和set方法,这样的好处是简洁工整,省去了不必要得代码
- @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 //类似Struts的Action public class TestController { @RequestMapping("test/login.do") // 请求url地址映射,类似Struts的action-mapping public String testLogin(@RequestParam(value="username")String username, String password, HttpServletRequest request) { // @RequestParam是指请求url地址映射中必须含有的参数(除非属性required=false) // @RequestParam可简写为:@RequestParam("username") if (!"admin".equals(username) || !"admin".equals(password)) { return "loginError"; // 跳转页面路径(默认为转发),该路径不需要包含spring-servlet配置文件中配置的前缀和后缀 } return "loginSuccess"; } @RequestMapping("/test/login2.do") public ModelAndView testLogin2(String username, String password, int age){ // request和response不必非要出现在方法中,如果用不上的话可以去掉 // 参数的名称是与页面控件的name相匹配,参数类型会自动被转换 if (!"admin".equals(username) || !"admin".equals(password) || age < 5) { return new ModelAndView("loginError"); // 手动实例化ModelAndView完成跳转页面(转发),效果等同于上面的方法返回字符串 } return new ModelAndView(new RedirectView("../index.jsp")); // 采用重定向方式跳转页面 // 重定向还有一种简单写法 // return new ModelAndView("redirect:../index.jsp"); } @RequestMapping("/test/login3.do") public ModelAndView testLogin3(User user) { // 同样支持参数为表单对象,类似于Struts的ActionForm,User不需要任何配置,直接写即可 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") // 获取applicationContext.xml中bean的id为loginService的,并注入 private LoginService loginService; //等价于spring传统注入方式写get和set方法,这样的好处是简洁工整,省去了不必要得代码 @RequestMapping("/test/login4.do") public String testLogin4(User user) { if (loginService.login(user) == false) { return "loginError"; } return "loginSuccess"; } }
其实RequestMapping在Class上,可看做是父Request请求url,而RequestMapping在方法上的可看做是子Request请求url,父子请求url最终会拼起来与页面请求url进行匹配,因此RequestMapping也可以这么写:
查看源码打印?
- package controller;
- import org.springframework.stereotype.Controller;
- import org.springframework.web.bind.annotation.RequestMapping;
- @Controller
- @RequestMapping("/test3/*") // 父request请求url
- public class TestController3 {
- @RequestMapping("login.do") // 子request请求url,拼接后等价于/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请求url public class TestController3 { @RequestMapping("login.do") // 子request请求url,拼接后等价于/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、结束语
掌握以上这些Spring
MVC就已经有了很好的基础了,几乎可应对与任何开发,在熟练掌握这些后,便可更深层次的灵活运用的技术,如多种视图技术,例如
Jsp、Velocity、Tiles、iText 和 POI。Spring MVC框架并不知道使用的视图,所以不会强迫您只使用 JSP 技术。