現在主流的Web MVC框架除了Struts這個主力 外,其次就是Spring MVC了,因此這也是作爲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)
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< servlet-name >spring</ servlet-name > |
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< servlet-class >org.springframework.web.servlet.DispatcherServlet</ servlet-class > |
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< load-on-startup >1</ load-on-startup > |
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< servlet-name >spring</ servlet-name > |
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< url-pattern >*.do</ url-pattern > |
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< listener-class >org.springframework.web.context.ContextLoaderListener</ listener-class > |
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< param-name >contextConfigLocation</ param-name > |
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< param-value >classpath:config/applicationContext.xml</ param-value > |
3. spring-servlet.xml配置
spring-servlet這個名字是因爲上面web.xml中<servlet-name>標籤配的值爲spring(<servlet-name>spring</servlet-name>),再加上“-servlet”後綴而形成的spring-servlet.xml文件名,如果改爲springMVC,對應的文件名則爲springMVC-servlet.xml。
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<? xml version = "1.0" encoding = "UTF-8" ?> |
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< beans xmlns = "http://www.springframework.org/schema/beans" |
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xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" xmlns:p = "http://www.springframework.org/schema/p" |
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xmlns:context = "http://www.springframework.org/schema/context" |
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xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd |
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http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd |
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http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd |
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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 >"> |
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< context:annotation-config /> |
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< context:component-scan base-package = "controller" ></ context:component-scan > |
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< bean class = "org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" /> |
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< bean class = "org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix = "/jsp/" p:suffix = ".jsp" /> |
4. applicationContext.xml配置
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<? xml version = "1.0" encoding = "UTF-8" ?> |
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< beans xmlns = "http://www.springframework.org/schema/beans" |
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xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" |
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xmlns:aop = "http://www.springframework.org/schema/aop" |
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xmlns:tx = "http://www.springframework.org/schema/tx" |
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http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd |
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http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-2.5.xsd |
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http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"> |
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< bean id = "sessionFactory" class = "org.springframework.orm.hibernate3.LocalSessionFactoryBean" > |
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< property name = "configLocation" > |
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< value >classpath:config/hibernate.cfg.xml</ value > |
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< bean id = "transactionManager" class = "org.springframework.orm.hibernate3.HibernateTransactionManager" > |
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< property name = "sessionFactory" > |
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< ref local = "sessionFactory" /> |
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< tx:annotation-driven transaction-manager = "transactionManager" proxy-target-class = "true" /> |
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< bean id = "loginService" class = "service.LoginService" ></ bean > |
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< bean id = "hibernateDao" class = "dao.HibernateDao" > |
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< property name = "sessionFactory" ref = "sessionFactory" ></ property > |
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,處理完後跳轉頁面。看如下代碼(註解):
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import javax.servlet.http.HttpServletRequest; |
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import org.springframework.stereotype.Controller; |
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import org.springframework.web.bind.annotation.RequestMapping; |
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import org.springframework.web.bind.annotation.RequestParam; |
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public class TestController
{ |
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@RequestMapping ( "test/login.do" ) |
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public String
testLogin( @RequestParam (value= "username" )String
username, String password, HttpServletRequest request) { |
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if (! "admin" .equals(username)
|| ! "admin" .equals(password))
{ |
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return "loginSuccess" ; |
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@RequestMapping ( "/test/login2.do" ) |
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public ModelAndView
testLogin2(String username, String password, int age){ |
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if (! "admin" .equals(username)
|| ! "admin" .equals(password)
|| age < 5 )
{ |
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return new ModelAndView( "loginError" ); |
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return new ModelAndView( new RedirectView( "../index.jsp" )); |
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@RequestMapping ( "/test/login3.do" ) |
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public ModelAndView
testLogin3(User user) { |
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String
username = user.getUsername(); |
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String
password = user.getPassword(); |
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int age
= user.getAge(); |
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if (! "admin" .equals(username)
|| ! "admin" .equals(password)
|| age < 5 )
{ |
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return new ModelAndView( "loginError" ); |
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return new ModelAndView( "loginSuccess" ); |
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@Resource (name
= "loginService" ) |
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private LoginService
loginService; |
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@RequestMapping ( "/test/login4.do" ) |
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public String
testLogin4(User user) { |
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if (loginService.login(user)
== false )
{ |
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return "loginSuccess" ; |
以上4個方法示例,是一個Controller裏含有不同的請求url,也可以採用一個url訪問,通過url參數來區分訪問不同的方法,代碼如下:
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import org.springframework.stereotype.Controller; |
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import org.springframework.web.bind.annotation.RequestMapping; |
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import org.springframework.web.bind.annotation.RequestMethod; |
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@RequestMapping ( "/test2/login.do" ) |
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public class TestController2
{ |
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public String
testLogin(String username, String password, int age)
{ |
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if (! "admin" .equals(username)
|| ! "admin" .equals(password)
|| age < 5 )
{ |
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return "loginSuccess" ; |
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@RequestMapping (params
= "method=1" ,
method=RequestMethod.POST) |
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public String
testLogin2(String username, String password) { |
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if (! "admin" .equals(username)
|| ! "admin" .equals(password))
{ |
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return "loginSuccess" ; |
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@RequestMapping (params
= "method=2" ) |
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public String
testLogin3(String username, String password, int age)
{ |
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if (! "admin" .equals(username)
|| ! "admin" .equals(password)
|| age < 5 )
{ |
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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也可以這麼寫:
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import org.springframework.stereotype.Controller; |
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import org.springframework.web.bind.annotation.RequestMapping; |
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@RequestMapping ( "/test3/*" ) |
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public class TestController3
{ |
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@RequestMapping ( "login.do" ) |
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public String
testLogin(String username, String password, int age)
{ |
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if (! "admin" .equals(username)
|| ! "admin" .equals(password)
|| age < 5 )
{ |
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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,在熟練掌握這些後,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。