spring 5 webflux异常处理

序

本文主要研究一下spring 5 webflux的异常处理

maven

        <dependency>
            <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-webflux</artifactId> </dependency> 

ExceptionHandler

由于webflux也支持传统spring mvc的大部分注解，因此原来的ExceptionHandler也是支持的。

@RestControllerAdvice
public class ExceptionHandlers { private static final Logger LOGGER = LoggerFactory.getLogger(ExceptionHandlers.class); @ExceptionHandler(Exception.class) @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR) public String serverExceptionHandler(Exception ex) { LOGGER.error(ex.getMessage(),ex); return ex.getMessage(); } } 

启动的时候可以看到日志

2018-02-12 19:26:03.249 INFO 7053 --- [ main] o.s.w.r.r.m.a.ControllerMethodResolver : Looking for @ControllerAdvice: org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext@65d09a04: startup date [Mon Feb 12 19:25:59 CST 2018]; root of context hierarchy 2018-02-12 19:26:03.281 INFO 7053 --- [ main] o.s.w.r.r.m.a.ControllerMethodResolver : Detected @ExceptionHandler methods in exceptionHandlers 

spring-webflux-5.0.2.RELEASE-sources.jar!/org/springframework/web/reactive/result/method/annotation/ControllerMethodResolver.java

/**
 * Package-private class to assist {@link RequestMappingHandlerAdapter} with
 * resolving, initializing, and caching annotated methods declared in
 * {@code @Controller} and {@code @ControllerAdvice} components: * <ul> * <li>{@code @InitBinder} * <li>{@code @ModelAttribute} * <li>{@code @RequestMapping} * <li>{@code @ExceptionHandler} * </ul> * * @author Rossen Stoyanchev * @since 5.0 */ class ControllerMethodResolver { private static Log logger = LogFactory.getLog(ControllerMethodResolver.class); private final List<SyncHandlerMethodArgumentResolver> initBinderResolvers; private final List<HandlerMethodArgumentResolver> modelAttributeResolvers; private final List<HandlerMethodArgumentResolver> requestMappingResolvers; private final List<HandlerMethodArgumentResolver> exceptionHandlerResolvers; private final ReactiveAdapterRegistry reactiveAdapterRegistry; //...... } 

可以看到支持InitBinder，ModelAttribute，RequestMapping，ExceptionHandler这几个注解。

实例

    @GetMapping(value = "/error",produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
    public Mono<String> exceptionReturn(){ // throw new RuntimeException("hello"); return Mono.error(new RuntimeException("test error")); } 

与传统mvc不同的是，除了直接throw异常外，Mono或Flux可以直接error一个异常，在exceptionHandlers都可以被接收处理

小结

webflux支持mvc的注解，是一个非常便利的功能，相比较于RouteFunction，自动扫描注册比较省事。异常处理可以沿用ExceptionHandler。

作者：go4it
转自：https://www.jianshu.com/p/ca89ea42a327