程序包 cn.taketoday.web

接口 ReturnValueHandler

所有已知子接口:

HandlerMethodReturnValueHandler, SmartReturnValueHandler

所有已知实现类:

AbstractMessageConverterMethodProcessor, AsyncTaskMethodReturnValueHandler, CallableMethodReturnValueHandler, DeferredResultReturnValueHandler, HttpEntityMethodProcessor, HttpHeadersReturnValueHandler, HttpStatusReturnValueHandler, MapMethodProcessor, ModelAttributeMethodProcessor, ModelMethodProcessor, ObjectHandlerMethodReturnValueHandler, RenderedImageReturnValueHandler, RequestResponseBodyMethodProcessor, ResponseBodyEmitterReturnValueHandler, ReturnValueHandlerDecorator, ReturnValueHandlerManager, SelectableReturnValueHandler, StreamingResponseBodyReturnValueHandler, ViewReturnValueHandler, VoidReturnValueHandler

public interface ReturnValueHandler

handler return-value Handler

Handle request-handler execution result

ReturnValueHandler is HTTP response writer

Note: This framework allows request-handler implement this interface to handle its execution result

作者:

TODAY 2019-07-10 19:22

另请参阅:

• HandlerExceptionHandler
• HandlerMethod

字段概要

字段

修饰符和类型	字段	说明
static final Object	NONE_RETURN_VALUE

方法概要

修饰符和类型	方法	说明
void	handleReturnValue(RequestContext context, Object handler, Object returnValue)	Handle result of the handler
static ReturnValueHandler	select(List<ReturnValueHandler> handlers, Object handler, Object returnValue)	Multiple ReturnValueHandlers under the ReturnValueHandler system choose different ReturnValueHandlers corresponding to different handler and returnValue
boolean	supportsHandler(Object handler)	If this ReturnValueHandler supports the target handler
default boolean	supportsReturnValue(Object returnValue)	If this ReturnValueHandler supports the target handler's result

字段详细资料

NONE_RETURN_VALUE

static final Object NONE_RETURN_VALUE

方法详细资料

supportsHandler

boolean supportsHandler(Object handler)

If this ReturnValueHandler supports the target handler

This method can test this ReturnValueHandler supports the target handler in application startup time , static match

参数:

handler - Target HTTP handler

返回:

If this ReturnValueHandler supports the target handler

supportsReturnValue

default boolean supportsReturnValue(@Nullable
 Object returnValue)

If this ReturnValueHandler supports the target handler's result

This method can test this ReturnValueHandler supports the target handler in application runtime

参数:

returnValue - Target handler's return-value or result

返回:

If this ReturnValueHandler supports the target handler's result

从以下版本开始:

4.0

handleReturnValue

void handleReturnValue(RequestContext context,
 @Nullable
 Object handler,
 @Nullable
 Object returnValue)
                throws Exception

Handle result of the handler

参数:

context - Current HTTP request context

handler - Target HTTP handler

returnValue - Handler execution result Or HandlerExceptionHandler return value

抛出:

Exception - return-value handled failed

select

@Nullable
static ReturnValueHandler select(List<ReturnValueHandler> handlers,
 @Nullable
 Object handler,
 @Nullable
 Object returnValue)

Multiple ReturnValueHandlers under the ReturnValueHandler system choose different ReturnValueHandlers corresponding to different handler and returnValue

参数:

handlers - Multiple ReturnValueHandlers

handler - Request handler

returnValue - handler's result ,if returnValue is NONE_RETURN_VALUE match handler only

返回:

A ReturnValueHandler that matches the situation , null if returnValue is NONE_RETURN_VALUE or no one matched