Introduction

to learn spring web mvc.

在spring mvc 中是WebApplicationContext, 继承了ApplicationContext ,就多了一个方法，获取ServletContext.

hierarchy

在web.xml中使用ContextLoaderListener配置RootWebApplicationContext.可以初始化一些公共的service/repository等。
dispatcherServlet 继承自RootWebApplicationContext。
覆盖 DefaultListableBeanFactory.allowBeanDefinitionOverriding 默认允许覆盖

可以只配置dispatcherServlet。所有的controller必须在dispatcherServlet配置的容器中。

<context-param>
    <param-name>contextConfigLocation</param-name>
   <param-value>classpath:applicationContext.xml</param-value>
  </context-param>

用来初始化ContextLoaderListener配置RootWebApplicationContext。

    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>/WEB-INF/mvc-config.xml</param-value>
    </init-param>

用来初始化dispatcherServlet的webApplicationContext.

通过param-value指定配置文件。
param-value为空，不使用配置文件初始化。
不配置init-param，默认使用[dispatcherServlet名称]-config.xml.
controller 最好在DispatcherServlet中扫描，如果在RootWebApplication 中扫描，WebApplicationContext 中不能配置<mvc:annotation-driven></mvc:annotation-driven> ,否则会使用子容器中的RequestMappingInfoHandlerMapping。

mvc:annotation-driven

这个是必须的，用来启动springmvc的基础设施。

context:annotation-config

context:annotation-config/ only looks for annotations on beans in the same application context in which it is defined. This means that, if you put context:annotation-config/ in a WebApplicationContext for a DispatcherServlet, it only checks for @Autowired beans in your controllers, and not your services. The use of context:component-scan implicitly enables the functionality of context:annotation-config. There is usually no need to include the context:annotation-config element when using context:component-scan.

process

来自http://gearever.iteye.com/blog/1841586

Tomcat
  Server 一个tomcat实例
  |  1:n
  |-- service
         | 
         |-- connector 
         |       
         |-- executor
         |  request/response
         |-- engine
               |
               |-- host
               |-- context (web applications)

     
Spring
request -> Locale Resolver-> theme Resolver ->|Interceptors                | 
                                 ^            |      preHandle             |    
                                 |            |      -- MappingHandler --  |  ExceptionsChain             
                        View Resolver<-model<-|      postHandle            |     
                                              |      afterCompletion       |          
                                              |                            |

Note that postHandle is less useful with @ResponseBody and ResponseEntity methods for which the response is written and committed within the HandlerAdapter and before postHandle. That means it is too late to make any changes to the response, such as adding an extra header. For such scenarios, you can implement ResponseBodyAdvice and either declare it as an Controller Advice bean or configure it directly on RequestMappingHandlerAdapter.

spring session

会引起频繁的youngGC 使用SpringHttpSessionConfiguration.springSessionRepositoryFilter 注册bean 所以必须在ContextLoaderListener初始化session配置，并且filter名称必须是springSessionRepositoryFilter

transaction

默认只回滚RuntimeException和Error,所以要指定rollbackFor InfrastructureAdvisorAutoProxyCreator实现了BeanPostProcessor. 事务注意事项

public
类内部调用无效
默认只回滚RuntimeException 和Error

@schedule 使用BeanPostProcessor 把使用注解的方法单独拉出来创建了个Runnable对象进行调度，依赖jdk调度 cron 使用的是固定延时调度 ScheduledExecutorService

notice

BeanPostProcessor/BeanFactoryPostProcessor 只对当前容器中的bean有效
context:component-scan 默认会开启context:annotation-config

skyding228 / springmvc-learn