doc: 阅读webflux controller文档

spring/webflux/spring webflux.md

@@ -320,3 +320,127 @@ webflux应用中包含的spring configuration通常包括：
 - 被委托给`webHandler`的beans
 - 其他
 
+上述配置将被被`WebHttpHandlerBuilder`使用，用于构建process chain，示例如下所示：
+```java
+ApplicationContext context = ...
+HttpHandler handler = WebHttpHandlerBuilder.applicationContext(context).build();
+```
+上述示例中返回的handler可以和`server adapter`结合使用。
+
+### DispatcherHandler委托
+`DispatcherHandler`会将请求的委托给特定的bean对象，bean对象会处理请求并且将结果渲染到response中。
+
+DispatcherHandler会对如下类型的bean进行auto-detect。
+
+<table id="webflux-special-beans-table" class="tableblock frame-all grid-all stripes-odd stretch">
+<colgroup>
+<col style="width: 33.3333%;">
+<col style="width: 66.6667%;">
+</colgroup>
+<thead>
+<tr>
+<th class="tableblock halign-left valign-top">Bean type</th>
+<th class="tableblock halign-left valign-top">Explanation</th>
+</tr>
+</thead>
+<tbody>
+<tr>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>HandlerMapping</code></p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">Map a request to a handler. The mapping is based on some criteria, the details of
+  which vary by <code>HandlerMapping</code> implementation — annotated controllers, simple
+  URL pattern mappings, and others.</p>
+<p class="tableblock">  The main <code>HandlerMapping</code> implementations are <code>RequestMappingHandlerMapping</code> for
+  <code>@RequestMapping</code> annotated methods, <code>RouterFunctionMapping</code> for functional endpoint
+  routes, and <code>SimpleUrlHandlerMapping</code> for explicit registrations of URI path patterns
+  and <code>WebHandler</code> instances.</p></td>
+</tr>
+<tr>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>HandlerAdapter</code></p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">Help the <code>DispatcherHandler</code> to invoke a handler mapped to a request regardless of
+  how the handler is actually invoked. For example, invoking an annotated controller
+  requires resolving annotations. The main purpose of a <code>HandlerAdapter</code> is to shield the
+  <code>DispatcherHandler</code> from such details.</p></td>
+</tr>
+<tr>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>HandlerResultHandler</code></p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">Process the result from the handler invocation and finalize the response.
+  See <a href="#webflux-resulthandling">Result Handling</a>.</p></td>
+</tr>
+</tbody>
+</table>
+
+### Processing
+`DispatcherHandler`按照如下方式处理请求：
+- 首先，会挨个查询`HandlerMapping`用于查找匹配的handler，会匹配第一个匹配的handler
+- 如果匹配到handler，会通过对应的HandlerAdapter执行该handler，并且会将handler返回的值作为`HandlerResult`暴露
+- `HandlerResult`将会被分配给指定的`HandlerResultHandler`进行处理，可能会直接向response中写入数据或渲染view
+
+### Result Handling
+通过`HandlerAdapter`对handler进行调用，返回的结果会被包裹在`HandlerResult`中，随之还包含额外的上下文。
+
+`HandlerResult`将会被传递给第一个支持其的上下文，下表中展示了`HandlerResultHandler`的实现：
+
+<table class="tableblock frame-all grid-all stripes-odd stretch">
+<colgroup>
+<col style="width: 25%;">
+<col style="width: 50%;">
+<col style="width: 25%;">
+</colgroup>
+<thead>
+<tr>
+<th class="tableblock halign-left valign-top">Result Handler Type</th>
+<th class="tableblock halign-left valign-top">Return Values</th>
+<th class="tableblock halign-left valign-top">Default Order</th>
+</tr>
+</thead>
+<tbody>
+<tr>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>ResponseEntityResultHandler</code></p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>ResponseEntity</code>, typically from <code>@Controller</code> instances.</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">0</p></td>
+</tr>
+<tr>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>ServerResponseResultHandler</code></p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>ServerResponse</code>, typically from functional endpoints.</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">0</p></td>
+</tr>
+<tr>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>ResponseBodyResultHandler</code></p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">Handle return values from <code>@ResponseBody</code> methods or <code>@RestController</code> classes.</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">100</p></td>
+</tr>
+<tr>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>ViewResolutionResultHandler</code></p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>CharSequence</code>, <a href="https://docs.spring.io/spring-framework/docs/6.2.3/javadoc-api/org/springframework/web/reactive/result/view/View.html"><code>View</code></a>,
+  <a href="https://docs.spring.io/spring-framework/docs/6.2.3/javadoc-api/org/springframework/ui/Model.html">Model</a>, <code>Map</code>,
+  <a href="https://docs.spring.io/spring-framework/docs/6.2.3/javadoc-api/org/springframework/web/reactive/result/view/Rendering.html">Rendering</a>,
+  or any other <code>Object</code> is treated as a model attribute.</p>
+<p class="tableblock">  See also <a href="#webflux-viewresolution">View Resolution</a>.</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code>Integer.MAX_VALUE</code></p></td>
+</tr>
+</tbody>
+</table>
+
+## Annotated Controllers
+spring webflux提供了基于注解的编程模型，通过使用注解来向外暴露request mappings。通过注解标注的controllers可包含灵活的方法签名，并且无需继承任何基类或实现指定接口。
+
+使用示例如下所示：
+```java
+@RestController
+public class HelloController {
+
+	@GetMapping("/hello")
+	public String handle() {
+		return "Hello WebFlux";
+	}
+}
+```
+
+### @Controller
+在基于注解的webflux变成模型中，可以使用`@Controller`或`@RestController`来声明controller bean。
+
+#### AOP
+对于部分场景，需要在运行时使用aop proxy来对controller进行decorate。
+
+对于针对controller的aop，推荐使用`class-based proxy`，可以使用`@EnableTransactionManagement(proxyTargetClass=true)`来实现。
+