SpringMVC参数解析及结果处理学习笔记

Controller处理概述

1. RequestMappingHandlerAdapter.invokeHandlerMethod调用ServletInvocableHandlerMethod.invokeAndHandle
2. 获取Controller参数并执行

    InvocableHandlerMethod.invokeForRequest{
         Object[] args = HandlerMethodArgumentResolverComposite.resolveArgument# 这里从 
         Object returnValue = doInvoke(args);
         return returnValue ;
    }
   

3. 处理Controller返回结果

   HandlerMethodReturnValueHandlerComposite.handleReturnValue{
      HandlerMethodReturnValueHandler handler = selectHandler(returnValue, returnType);
      handler.handleReturnValue(returnValue, returnType, mavContainer, webRequest);
    }
   

获取Controller参数并执行

1. resolveArgument解析controller方法的每一个参数类型放入MethodParameter[]数组中
2. 遍历MethodParameter对象，使用HandlerMethodArgumentResolverComposite.supportsParameter(MethodParameter parameter)
3. HandlerMethodArgumentResolverComposite.getArgumentResolver获取能处理MethodParameter的XXXResolver，
   以RequestResponseBodyMethodProcessor为例，继续以下逻辑

   0 = {RequestParamMethodArgumentResolver@6275} 
   1 = {RequestParamMapMethodArgumentResolver@6276} 
   2 = {PathVariableMethodArgumentResolver@6277} 
   3 = {PathVariableMapMethodArgumentResolver@6278} 
   4 = {MatrixVariableMethodArgumentResolver@6279} 
   5 = {MatrixVariableMapMethodArgumentResolver@6280} 
   6 = {ServletModelAttributeMethodProcessor@6281} 
   7 = {RequestResponseBodyMethodProcessor@6282} 
   8 = {RequestPartMethodArgumentResolver@6283} 
   9 = {RequestHeaderMethodArgumentResolver@6284} 
   10 = {RequestHeaderMapMethodArgumentResolver@6285} 
   11 = {ServletCookieValueMethodArgumentResolver@6286} 
   12 = {ExpressionValueMethodArgumentResolver@6287} 
   13 = {SessionAttributeMethodArgumentResolver@6288} 
   14 = {RequestAttributeMethodArgumentResolver@6289} 
   15 = {ServletRequestMethodArgumentResolver@6290} 
   16 = {ServletResponseMethodArgumentResolver@6291} 
   17 = {HttpEntityMethodProcessor@6292} 
   18 = {RedirectAttributesMethodArgumentResolver@6293} 
   19 = {ModelMethodProcessor@6294} 
   20 = {MapMethodProcessor@6295} 
   21 = {ErrorsMethodArgumentResolver@6296} 
   22 = {SessionStatusMethodArgumentResolver@6297} 
   23 = {UriComponentsBuilderMethodArgumentResolver@6298} 
   24 = {PrincipalMethodArgumentResolver@6299} 
   25 = {RequestParamMethodArgumentResolver@6300} 
   26 = {ServletModelAttributeMethodProcessor@6301} 
   

4. 根据3中获取到的RequestResponseBodyMethodProcessor调用resolveArgument=>readWithMessageConverters
5. 遍历RequestResponseBodyMethodProcessor中的HttpMessageConverter集合，调用canRead判断Converter是否能支持解析参数

   0 = {ByteArrayHttpMessageConverter@6254} 
   1 = {StringHttpMessageConverter@6255} 
   2 = {StringHttpMessageConverter@6256} 
   3 = {ResourceHttpMessageConverter@6257} 
   4 = {ResourceRegionHttpMessageConverter@6258} 
   5 = {SourceHttpMessageConverter@6259} 
   6 = {AllEncompassingFormHttpMessageConverter@6260} 
   7 = {MappingJackson2HttpMessageConverter@6261} 
   8 = {MappingJackson2HttpMessageConverter@6262} 
   

6. 通过MappingJackson2HttpMessageConverter读取数据

处理Controller返回结果

1. selectHandler(returnValue, returnType)遍历ReturnValueHandler根据supportsReturnType选取,
   以RequestResponseBodyMethodProcessor为例,因被@ResponseBody注解所以被选中

   0 = {ModelAndViewMethodReturnValueHandler@6200} 
   1 = {ModelMethodProcessor@6201} 
   2 = {ViewMethodReturnValueHandler@6202} 
   3 = {ResponseBodyEmitterReturnValueHandler@6203} 
   4 = {StreamingResponseBodyReturnValueHandler@6204} 
   5 = {HttpEntityMethodProcessor@6205} 
   6 = {HttpHeadersReturnValueHandler@6206} 
   7 = {CallableMethodReturnValueHandler@6207} 
   8 = {DeferredResultMethodReturnValueHandler@6208} 
   9 = {AsyncTaskMethodReturnValueHandler@6209} 
   10 = {ModelAttributeMethodProcessor@6210} 
   11 = {RequestResponseBodyMethodProcessor@6211} 
   12 = {ViewNameMethodReturnValueHandler@6212} 
   13 = {MapMethodProcessor@6213} 
   14 = {ModelAttributeMethodProcessor@6214} 
   

2. handler.handleReturnValue处理返回结果 => RequestResponseBodyMethodProcessor.writeWithMessageConverters
3. 根据request获取accept头对应的MediaType集合，
4. 获取controller对应的MediaType集合，如果controller未标注produces，则遍历messageConvert，
   根据canWrite(返回结果类型)，将messageConvert支持的MediaType集合

   0 = {PropertiesHttpMessageConverter@6332} 
   1 = {ByteArrayHttpMessageConverter@6333} 
   2 = {StringHttpMessageConverter@6334} 
   3 = {StringHttpMessageConverter@6335} 
   4 = {ResourceHttpMessageConverter@6336} 
   5 = {ResourceRegionHttpMessageConverter@6337} 
   6 = {SourceHttpMessageConverter@6338} 
   7 = {AllEncompassingFormHttpMessageConverter@6339} 
   8 = {MappingJackson2HttpMessageConverter@6340} 
   9 = {MappingJackson2HttpMessageConverter@6341} 
   

5. 遍历3集合与4集合逐个匹配，并将结果集排序，获取最优的MediaType
6. 遍历所有的messageConverters根据canWrite(返回值类型,MediaType)选出messageConverter
   并调用write将结果写回客户端

Type
6. 遍历所有的messageConverters根据canWrite(返回值类型,MediaType)选出messageConverter
并调用write将结果写回客户端