image.png

整体过程

1. 发起请求到前端控制器(DispatcherServlet)
2. 前端控制器请求HandlerMapping查找Handler
   可以根据xml配置， 注解进行查找
3. 处理器映射器HandlerMapping 向前端控制器返回Handler
4. 前端控制器调用处理器适配handleAdapter器去执行Handler
5. 处理器适配器去执行handler
6. handler执行完成给适配器返回modelandview
7. 处理器适配器向前端控制器返回modelAndview
   modelandview是springmvc框架的 一个底层对象，包括modelandview
8. 前端控制器请求视图解析器去进行视图解析
9. 视图解析器向前端控制器返回view
10. 前端控制器进行视图渲染
    视图渲染将Modelandview中的数据填充到response域
    11.前端控制器向用户响应结果

基于非注解的配置

• 使用

<bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"></bean>
    <bean class="org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter"></bean>

要注意对应的handler需要分别实现对应的接口才会被适配器所执行

public class HttpRequestHandlerAdapter implements HandlerAdapter {
    @Override
    public boolean supports(Object handler) {
        return (handler instanceof HttpRequestHandler);
    }
}
public class SimpleControllerHandlerAdapter implements HandlerAdapter {
    @Override
    public boolean supports(Object handler) {
        return (handler instanceof Controller);
    }
}

这两种也是dispatcher的默认配置，所以不需要在dispatcher-servlet.xml中显式配置也可以。默认配置文件可以在对应jar包(org.springframework.web.servlet)中获取

# Default implementation classes for DispatcherServlet's strategy interfaces.
# Used as fallback when no matching beans are found in the DispatcherServlet context.
# Not meant to be customized by application developers.

org.springframework.web.servlet.LocaleResolver=org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver

org.springframework.web.servlet.ThemeResolver=org.springframework.web.servlet.theme.FixedThemeResolver

org.springframework.web.servlet.HandlerMapping=org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping,\
    org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping

org.springframework.web.servlet.HandlerAdapter=org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,\
    org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,\
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter

org.springframework.web.servlet.HandlerExceptionResolver=org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerExceptionResolver,\
    org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver,\
    org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver

org.springframework.web.servlet.RequestToViewNameTranslator=org.springframework.web.servlet.view.DefaultRequestToViewNameTranslator

org.springframework.web.servlet.ViewResolver=org.springframework.web.servlet.view.InternalResourceViewResolver

org.springframework.web.servlet.FlashMapManager=org.springframework.web.servlet.support.SessionFlashMapManager

基于注解的方式配置

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

    <!--<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"></bean>-->
    <!--<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"></bean>-->
    <!--mvc:annotation-driven可以用来代替以上RequestMappingHandlerMapping和RequestMappingHandlerAdapter 的关系-->
    <mvc:annotation-driven></mvc:annotation-driven>

    <context:component-scan base-package="com.vee.controller"></context:component-scan>
    <!--视图解析器，解析jsp，默认使用jstl标签-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!--配置前缀和后缀就可以在写modleAndView的viewName的时候不用写出完整的绝对路径名-->
        <property name="prefix" value="/WEB-INF/jsp/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
</beans>

同时web.xml中servlet也要修改成annotationdispatcher

      <servlet>
        <servlet-name>annotationdispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>annotationdispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

使用注解的Controller类

//使用注解标识的控制器
@Controller
public class AnnotationHandler {
    @RequestMapping("/wocaolei")
    public ModelAndView handle(){
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("mesg", "annotationHandler..");
        //这个是没有使用前后缀的完整路径
        modelAndView.setViewName("/WEB-INF/jsp/welcome.jsp");
        return modelAndView;
    }
    //如果返回结果是字符串adapter会把他当成modelAndView中的viewName 来处理
    @RequestMapping("/wocaolei2")
    public String handle2(){
        System.out.println("annotation handle2");
        return  "welcome";
    }
}