架构师进阶之路——3、Spring MVC 源码深度剖析(二)

男娘i 2022-10-06 12:54 136阅读 0赞

**目录**

一、SpringMVC处理请求源码分析

1、前端控制器 DispatcherServlet 继承结构

2、SpringMVC处理请求流程

3、核心方法深度剖析

1）getHandler方法剖析

2）getHandlerAdapter方法剖析

3）ha.handle方法剖析

4）processDispatchResult方法剖析

二、SpringMVC九大组件初始化

1、九大组件

2、九大组件的初始化时机

3、Spring与Spring MVC 初始化的关联性

--------------------

# 一、SpringMVC处理请求源码分析 #

## 1、前端控制器 DispatcherServlet 继承结构 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70][]

## 2、SpringMVC处理请求流程 ##

1) 调用getHandler()获取到能够处理当前请求的执行链 HandlerExecutionChain(Handler+拦截器)

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 1][]

2)调用getHandlerAdapter();获取能够执行1)中Handler的适配器

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 2][]

3)适配器调用Handler执行ha.handle(总会返回一个ModelAndView对象)

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 3][]

调用processDispatchResult()方法完成视图渲染跳转

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 4][]

## 3、核心方法深度剖析 ##

### 1）getHandler方法剖析 ###

遍历两个HandlerMapping，试图获取能够处理当前请求的执行链

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 5][]

### 2）getHandlerAdapter方法剖析 ###

遍历各个HandlerAdapter，看哪个Adapter支持处理当前Handler

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 6][]

### 3）ha.handle方法剖析 ###

进入

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 7][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 8][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 9][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 10][]

### 4）processDispatchResult方法剖析 ###

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 11][]

# 二、SpringMVC九大组件初始化 #

## 1、九大组件 ##

在DispatcherServlet中定义了九个属性，每一个属性都对应一种组件

/** MultipartResolver used by this servlet. */ 
    // 多部件解析器
    @Nullable
    private MultipartResolver multipartResolver;
    /** LocaleResolver used by this servlet. */ 
    // 区域化 国际化解析器
    @Nullable
    private LocaleResolver localeResolver;
    /** ThemeResolver used by this servlet. */ 
    // 主题解析器
    @Nullable
    private ThemeResolver themeResolver;
    /** List of HandlerMappings used by this servlet. */ 
    // 处理器映射器组件
    @Nullable
    private List<HandlerMapping> handlerMappings;
    /** List of HandlerAdapters used by this servlet. */ 
    // 处理器适配器组件
    @Nullable
     
    private List<HandlerAdapter> handlerAdapters;
    /** List of HandlerExceptionResolvers used by this servlet. */ 
    // 异常解析器组件
    @Nullable
    private List<HandlerExceptionResolver> handlerExceptionResolvers;
    /** RequestToViewNameTranslator used by this servlet. */ 
    // 默认视图名转换器组件
    @Nullable
    private RequestToViewNameTranslator viewNameTranslator;
    /** FlashMapManager used by this servlet. */ 
    // flash属性管理组件
    @Nullable
    private FlashMapManager flashMapManager;
    /** List of ViewResolvers used by this servlet. */ 
    // 视图解析器
    @Nullable
    private List<ViewResolver> viewResolvers;

##  2、九大组件的初始化时机 ##

DispatcherServlet中的onRefresh()，该方法中初始化了九大组件

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 12][]

观察其中的一个组件initHandlerMappings(context)

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 13][]

##  3、Spring与Spring MVC 初始化的关联性 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 14][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 15][]

在spring启动的时候发布时间监听，通过监听来出发dispatcherServlet的onReFresh()，从而加载spring mvc的相关组件

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 16][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70]: /images/20221005/1ab6f24cc0c74febb03ba2717c290d76.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 1]: /images/20221005/a06f1117594340f49b24d52d070556ae.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 2]: /images/20221005/8f6b42efa65547cd961c4b8d2c7bf1d0.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 3]: /images/20221005/31aeb0304be54c2ab8f5b03f4762d378.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 4]: /images/20221005/91fe87a278f84f87bdee5eeee3ceb10a.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 5]: /images/20221005/6b2469114f33437dba9f5287f6bae4da.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 6]: /images/20221005/2b73b09e812f4d77a3a53e8a79c37115.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 7]: /images/20221005/1bafbab8cfd3495796f94a707e138081.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 8]: /images/20221005/278196483dcc4abe9c85f6ee5c1ea4b4.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 9]: /images/20221005/73bca4318ce54a35a16289b72fbfb174.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 10]: /images/20221005/7e6ca14f4b5f48fdbc92eb1c9ddd0615.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 11]: /images/20221005/1de9e2e8bb4d4be3b383758569a15793.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 12]: /images/20221005/f88d6a558cf9464cab42a4d41ae6f224.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 13]: /images/20221005/fb52825048614de69a35394b89249e68.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 14]: /images/20221005/e963b37a5b8a48cb95f0a7c5a61f4de1.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 15]: /images/20221005/6ca14f774db045ab934a76c1b52f7003.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTA5NTA4_size_16_color_FFFFFF_t_70 16]: /images/20221005/cf7d208d0a8d47daa12306bb3005ae34.png