spring mvc 起步

1：mvc的核心思想是业务数据抽取同业务数据呈现相分离

2：HandlerAdapter用来处理handleinterceptor和 ControlInter 生成的handleExecuteChain

   请求 diapatcherServlet 接受请求，--> 交给handleMapper处理，返回一个 handleExecuteChain(包含拦截器和相应的handle) -->先执行注册的拦截器，在交给HandleAdapt 执行相应的handl,返回一个modleAndView.

3：mode ModelAndView map

4:为了防止用Maven管理Spring项目时，不同的项目依赖了不同版本的Spring，可以使用Maven BOM来解决者一问题。

在依赖管理时，引入spring-framework-bom，如：

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-framework-bom</artifactId>
            <version>4.3.1.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

即可统一版本，而且，在引入BOM之后，在引入其他Spring依赖时，都无需指定版本，如：

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
    </dependency>
<dependencies>

5:配置文件

WEB-INF

      web.xml

       spring

             applicationContext.xml

             mvc-dispatcher-servlet.xml

 

内容如下：

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
   http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
  <display-name>Spring MVC Study</display-name>
  <!-- Spring应用上下文， 理解层次化的ApplicationContext -->
  <context-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>/WEB-INF/configs/spring/applicationContext*.xml</param-value>
  </context-param>
  
  <listener>
      <listener-class>
         org.springframework.web.context.ContextLoaderListener
      </listener-class>
  </listener>
  
  <!-- DispatcherServlet, Spring MVC的核心 --> 可有有多个DispatcherServlet

  <servlet>
      <servlet-name>mvc-dispatcher</servlet-name>
      <servlet-class> org.springframework.web.servlet.DispatcherServlet</servlet-class>
      <!-- DispatcherServlet对应的上下文配置， 默认为/WEB-INF/$servlet-name$-servlet.xml
       -->
      <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>/WEB-INF/configs/spring/mvc-dispatcher-servlet.xml</param-value>
        </init-param>
      <load-on-startup>1</load-on-startup>
   </servlet>
   <servlet-mapping>
      <servlet-name>mvc-dispatcher</servlet-name>
       <!-- mvc-dispatcher拦截所有的请求-->
      <url-pattern>/</url-pattern>
   </servlet-mapping>
</web-app>

applicationContext.xml如下：

<?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:context="http://www.springframework.org/schema/context"
   xmlns:mvc="http://www.springframework.org/schema/mvc"
   xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

   <context:annotation-config />

   <context:component-scan base-package="com.imooc.mvcdemo">
      <context:exclude-filter type="annotation"
         expression="org.springframework.stereotype.Controller" />
   </context:component-scan>
</beans>

mvc-dispatcher-servlet.xml如下：

<?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:context="http://www.springframework.org/schema/context"
   xmlns:mvc="http://www.springframework.org/schema/mvc"
   xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

   <!-- 本配置文件是工名为mvc-dispatcher的DispatcherServlet使用， 提供其相关的Spring MVC配置 -->

   <!-- 启用Spring基于annotation的DI, 使用户可以在Spring MVC中使用Spring的强大功能。 激活 @Required 
      @Autowired,JSR 250's @PostConstruct, @PreDestroy and @Resource 等标注 -->
   <context:annotation-config />

   <!-- DispatcherServlet上下文， 只管理@Controller类型的bean， 忽略其他型的bean, 如@Service -->
   <context:component-scan base-package="com.imooc.mvcdemo">
      <context:include-filter type="annotation"
         expression="org.springframework.stereotype.Controller" />
   </context:component-scan>

   <!-- HandlerMapping, 无需配置， Spring MVC可以默认启动。 DefaultAnnotationHandlerMapping 
      annotation-driven HandlerMapping -->

   <!-- 扩充了注解驱动，可以将请求参数绑定到控制器参数 -->
   <mvc:annotation-driven />

   <!-- 静态资源处理， css， js， imgs -->
   <mvc:resources mapping="/resources/**" location="/resources/" />


   <!-- 配置ViewResolver。 可以用多个ViewResolver。 使用order属性排序。 InternalResourceViewResolver放在最后。 -->
   <bean
      class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
      <property name="order" value="1" />
      <property name="mediaTypes">
         <map>
            <entry key="json" value="application/json" />
            <entry key="xml" value="application/xml" />
            <entry key="htm" value="text/html" />
         </map>
      </property>

      <property name="defaultViews">
         <list>
            <!-- JSON View -->
            <bean
               class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
            </bean>
         </list>
      </property>
      <property name="ignoreAcceptHeader" value="true" />
   </bean>

   <bean
      class="org.springframework.web.servlet.view.InternalResourceViewResolver">
      <property name="viewClass"
         value="org.springframework.web.servlet.view.JstlView" />
      <property name="prefix" value="/WEB-INF/jsps/" />
      <property name="suffix" value=".jsp" />
   </bean>


   <!--200*1024*1024即200M resolveLazily属性启用是为了推迟文件解析，以便捕获文件大小异常 -->
   <bean id="multipartResolver"
      class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
      <property name="maxUploadSize" value="209715200" />
      <property name="defaultEncoding" value="UTF-8" />
      <property name="resolveLazily" value="true" />
   </bean>

</beans>

6:参数接收

//本方法将处理 /courses/view?courseId=123 形式的URL
@RequestMapping(value="/view", method=RequestMethod.GET)
public String viewCourse(@RequestParam("courseId") Integer courseId,
Model model) {


log.debug("In viewCourse, courseId = {}", courseId);
Course course = courseService.getCoursebyId(courseId);
model.addAttribute(course);
return "course_overview";
}

//本方法将处理 /courses/view2/123 形式的URL
@RequestMapping("/view2/{courseId}")
public String viewCourse2(@PathVariable("courseId") Integer courseId,
Map<String, Object> model) {

log.debug("In viewCourse2, courseId = {}", courseId);
Course course = courseService.getCoursebyId(courseId);
model.put("course",course);
return "course_overview";
}

//本方法将处理 /courses/view3?courseId=123 形式的URL
@RequestMapping("/view3")
public String viewCourse3(HttpServletRequest request) {

Integer courseId = Integer.valueOf(request.getParameter("courseId"));
Course course = courseService.getCoursebyId(courseId);
request.setAttribute("course",course);

return "course_overview";
}

@RequestMapping(value="/admin", method = RequestMethod.GET, params = "add")
public String createCourse(){
return "course_admin/edit";
}

@RequestMapping(value="/save", method = RequestMethod.POST)
public String doSave(@ModelAttribute Course course){

log.debug("Info of Course:");
log.debug(ReflectionToStringBuilder.toString(course));

//在此进行业务操作，比如数据库持久化
course.setCourseId(123);
return "redirect:view2/"+course.getCourseId();
}

此处多了一个注解@ModelAttribute("user")，它的作用是将该绑定的命令对象以“user”为名称添加到模型对象中供视图页面展示使用。我们此时可以在视图页面使用${user.username}来获取绑定的命令对象的属性。

7：用到HttpServletRequest  需要引入

<dependency>
   <groupId>javax.servlet</groupId>
   <artifactId>servlet-api</artifactId>
   <version>2.5</version>
</dependency>

8： 对json的支持

@RequestMapping(value="/{courseId}",method=RequestMethod.GET)
public @ResponseBody Course getCourseInJson(@PathVariable Integer courseId){
return courseService.getCoursebyId(courseId);
}


@RequestMapping(value="/jsontype/{courseId}",method=RequestMethod.GET)
public ResponseEntity<Course> getCourseInJson2(@PathVariable Integer courseId){
Course course = courseService.getCoursebyId(courseId);
return new ResponseEntity<Course>(course, HttpStatus.OK);
}

需要引入

<dependency>
   <groupId>com.fasterxml.jackson.core</groupId>
   <artifactId>jackson-databind</artifactId>
   <version>${jackson.version}</version>
</dependency>

以及配置ViewResolver