Gateway Hystrix fallback获取异常信息
gateway fallback后,需要知道请求的是哪个接口以及具体的异常信息,根据不同的请求以及异常进行不同的处理。一开始根据网上一篇博客上的做法:
pom.xml:
1 2 3 4 5 6 7 8 | < dependency > < groupId >org.springframework.cloud</ groupId > < artifactId >spring-cloud-starter-gateway</ artifactId > </ dependency > < dependency > < groupId >org.springframework.cloud</ groupId > < artifactId >spring-cloud-starter-netflix-hystrix</ artifactId > </ dependency > |
application.yml:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | spring: cloud: gateway: discovery: locator: enabled: false lowerCaseServiceId: true routes: - id: auth-server predicates: - Path=/** default-filters: - name: Hystrix args: name: fallbackcmd fallbackUri: forward:/fallback |
然后fallback就是这样:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | @RestController @Slf4j public class FallbackController { @RequestMapping (value = "/fallback" ) @ResponseStatus public Mono<Map<String, Object>> fallback(ServerWebExchange exchange, Throwable throwable) { Map<String, Object> result = new HashMap<>( 3 ); ServerHttpRequest request = exchange.getRequest(); log.error( "接口调用失败,URL={}" , request.getPath().pathWithinApplication().value(), throwable); result.put( "code" , 60002 ); result.put( "data" , null ); result.put( "msg" , "接口调用失败!" ); return Mono.just(result); } } |
但是测试发现,这样取出来的接口地址只是“/fallback”本身,并且没有异常信息:
后来我重新到HystrixGatewayFilterFactory类中去查看,发现了异常信息其实在exchange里:
而请求的接口也通过debug找到了:
所以将代码改成如下:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | @RestController @Slf4j public class FallbackController { @RequestMapping (value = "/fallback" ) @ResponseStatus public Mono<Map<String, Object>> fallback(ServerWebExchange exchange) { Map<String, Object> result = new HashMap<>( 3 ); result.put( "code" , 60002 ); result.put( "data" , null ); Exception exception = exchange.getAttribute(ServerWebExchangeUtils.HYSTRIX_EXECUTION_EXCEPTION_ATTR); ServerWebExchange delegate = ((ServerWebExchangeDecorator) exchange).getDelegate(); log.error( "接口调用失败,URL={}" , delegate.getRequest().getURI(), exception); if (exception instanceof HystrixTimeoutException) { result.put( "msg" , "接口调用超时" ); } else if (exception != null && exception.getMessage() != null ) { result.put( "msg" , "接口调用失败: " + exception.getMessage()); } else { result.put( "msg" , "接口调用失败" ); } return Mono.just(result); } } |
正常取到请求路径以及异常信息:
关于 hystrix 的异常 fallback method wasn't found
消费者服务--service 的实现如下:
1 2 3 4 5 6 7 8 9 10 11 12 13 | @Service public class BookService { @Autowired public RestTemplate restTemplate; @HystrixCommand (fallbackMethod = "addServiceFallback" ) public Book getBook( Integer bookId ){ return restTemplate.getForObject( "http://provider-service/boot/book?bookId={bookId}" ,Book. class , bookId); } public String addServiceFallback(){ System.out.println( "error addServiceFallback.... " ); return "error" ; } } |
就会出现如下所述的异常
Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.Fri May 25 14:27:51 CST 2018
There was an unexpected error (type=Internal Server Error, status=500).
fallback method wasn't found: addServiceFallback([class java.lang.Integer])
这是因为指定的 备用方法 addServiceFallback 和 原方法getBook 的参数个数,参数类型 不同造成的;
修改addServiceFallback 方法:
1 2 3 4 | public String addServiceFallback(Integer bookId){ System.out.println( "error addServiceFallback.... " ); return "error" ; } |
继续运行,就会出现如下所述的异常
Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.Fri May 25 14:32:24 CST 2018
There was an unexpected error (type=Internal Server Error, status=500).
Incompatible return types. Command method: public com.bmcc.springboot.model.Book com.bmcc.springboot.service.BookService.getBook(java.lang.Integer); Fallback method: public java.lang.String com.bmcc.springboot.service.BookService.addServiceFallback(java.lang.Integer); Hint: Fallback method 'public java.lang.String com.bmcc.springboot.service.BookService.addServiceFallback(java.lang.Integer)' must return: class com.bmcc.springboot.model.Book or its subclass
这是因为指定的 备用方法 addServiceFallback 和 原方法getBook 虽然 参数个数,参数类型 相同 ,但是 方法的返回值类型不同造成的;
修改addServiceFallback 方法:
1 2 3 4 | public Book addServiceFallback(Integer bookId){ System.out.println( "error addServiceFallback.... " ); return new Book() ; } |
继续运行,这样就可以看到当一个服务提供者异常关闭时, 消费者(消费者采用轮询的方式消费服务)再继续访问服务时,不会抛出异常页面,而是如下:
1 | { "bookId" : 0 , "bookName" : null , "price" : null , "publisher" : null } |
以上为个人经验,希望能给大家一个参考,也希望大家多多支持自学编程网。
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