Spring中HandlerMethod类源码详细解析

public class HandlerMethod {
	//bean名称，调试的时候看到是字符串控制器名称（首字母小写）
	private final Object bean;
  //bean工厂类，个人调试传入的是DefaultListableBeanFactory
	@Nullable
	private final BeanFactory beanFactory;
	//方法所属类
	private final Class<?> beanType;
	//控制器方法
	private final Method method;
	//桥接方法，如果method是原生的，这个属性就是method
	private final Method bridgedMethod;
	//封装方法参数实例
	private final MethodParameter[] parameters;
	//Http状态码
	@Nullable
	private HttpStatus responseStatus;
	//ResponseStatus注解的reason值
	@Nullable
	private String responseStatusReason;
	//使用createWithResolvedBean方法创建的HttpMethod方法对象
	@Nullable
	private HandlerMethod resolvedFromHandlerMethod;
	//getInterfaceParameterAnnotations获取
	@Nullable
	private volatile List<Annotation[][]> interfaceParameterAnnotations;
	//类描述，使用initDescription方法解析beanType和method获得
	private final String description;
}

	/**
	* 获取request请求参数，调用控制器方法
	**/
  @Nullable
	public Object invokeForRequest(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
			Object... providedArgs) throws Exception {
		//获取request请求方法的参数
		Object[] args = getMethodArgumentValues(request, mavContainer, providedArgs);
		if (logger.isTraceEnabled()) {
			logger.trace("Arguments: " + Arrays.toString(args));
		}
		return doInvoke(args);
	}

	/**
	* 使用给定的参数调用控制器方法
	**/
	@Nullable
	protected Object doInvoke(Object... args) throws Exception {
		ReflectionUtils.makeAccessible(getBridgedMethod());
		try {
      //调用真实最终的控制器方法，并返回执行后的结果
			return getBridgedMethod().invoke(getBean(), args);
		}
		catch (IllegalArgumentException ex) {
			assertTargetBean(getBridgedMethod(), getBean(), args);
			String text = (ex.getMessage() != null ? ex.getMessage() : "Illegal argument");
			throw new IllegalStateException(formatInvokeError(text, args), ex);
		}
		catch (InvocationTargetException ex) {
			// Unwrap for HandlerExceptionResolvers ...
			Throwable targetException = ex.getTargetException();
			if (targetException instanceof RuntimeException) {
				throw (RuntimeException) targetException;
			}
			else if (targetException instanceof Error) {
				throw (Error) targetException;
			}
			else if (targetException instanceof Exception) {
				throw (Exception) targetException;
			}
			else {
				throw new IllegalStateException(formatInvokeError("Invocation failure", args), targetException);
			}
		}
	}

	/**
	 * Invoke the method and handle the return value through one of the
	 * configured {@link HandlerMethodReturnValueHandler HandlerMethodReturnValueHandlers}.
	 * @param webRequest the current request
	 * @param mavContainer the ModelAndViewContainer for this request
	 * @param providedArgs "given" arguments matched by type (not resolved)
	 */
	public void invokeAndHandle(ServletWebRequest webRequest, ModelAndViewContainer mavContainer,
			Object... providedArgs) throws Exception {
		//调用父类InvocableHandlerMethod的回调方法，并返回调用接口控制器方法的返回结果
		Object returnValue = invokeForRequest(webRequest, mavContainer, providedArgs);
		setResponseStatus(webRequest);

		if (returnValue == null) {
			if (isRequestNotModified(webRequest) || getResponseStatus() != null || mavContainer.isRequestHandled()) {
				disableContentCachingIfNecessary(webRequest);
				mavContainer.setRequestHandled(true);
				return;
			}
		}
		else if (StringUtils.hasText(getResponseStatusReason())) {
			mavContainer.setRequestHandled(true);
			return;
		}

		mavContainer.setRequestHandled(false);
		Assert.state(this.returnValueHandlers != null, "No return value handlers");
		try {
      //将控制器返回的结果交给HandlerMethodReturnValueHandler来处理
			this.returnValueHandlers.handleReturnValue(
					returnValue, getReturnValueType(returnValue), mavContainer, webRequest);
		}
		catch (Exception ex) {
			if (logger.isTraceEnabled()) {
				logger.trace(formatErrorForReturnValue(returnValue), ex);
			}
			throw ex;
		}
	}