@SentinelResource 来指定出现限流和降级时候的异常处理策略

小咪咪 2022-11-24 14:13 80阅读 0赞

[使用@SentinelResource注解实现限流][SentinelResource]

## 1.降级或限流 ##

1.  示例

@GetMapping("/sentinel-resource")
        @SentinelResource(value = "test-sentinel",blockHandler = "handleException")
        public String byResource2(){ 
            return "sentinel-resource";
        }
        public String handleException(BlockException blockException){ 
            System.out.println("限流或降级了");
            return "限流或降级了";
        }

*  实例2.  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGVuZ3dlaTIzMDYxMg_size_16_color_FFFFFF_t_70]

@GetMapping("/test-sentinel-resource")
        @SentinelResource(
                value = "test-sentinel-api",
              blockHandler = "block",
            // blockHandlerClass = TestControllerBlockHandlerClass.class,
        )
        public String testSentinelResource(@RequestParam(required = false) String a) { 
            if (StringUtils.isBlank(a)) { 
                throw new IllegalArgumentException("a cannot be blank.");
            }
            return a;
        }
    
        /** * 处理限流或者降级 * * @param a * @param e * @return */
        public  String block(String a, BlockException e) { 
            log.warn("限流，或者降级了 block", e);
            return "限流，或者降级了 block";
        }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGVuZ3dlaTIzMDYxMg_size_16_color_FFFFFF_t_70 1]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGVuZ3dlaTIzMDYxMg_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGVuZ3dlaTIzMDYxMg_size_16_color_FFFFFF_t_70 3]

## 2.降级 ##

@GetMapping("/test-sentinel-resource")
        @SentinelResource(
                value = "test-sentinel-api",
            // blockHandler = "block",
            // blockHandlerClass = TestControllerBlockHandlerClass.class,
                fallback = "fallback"
        )
        public String testSentinelResource(@RequestParam(required = false) String a) { 
            if (StringUtils.isBlank(a)) { 
                throw new IllegalArgumentException("a cannot be blank.");
            }
            return a;
        }
    
        /** * 处理限流或者降级 * * @param a * @param e * @return */
        public  String block(String a, BlockException e) { 
            log.warn("限流，或者降级了 block", e);
            return "限流，或者降级了 block";
        }
    
        /** * 1.5 处理降级 * - sentinel 1.6 可以处理Throwable * * @param a * @return */
        public String fallback(String a) { 
            return "限流，或者降级了 fallback";
        }

## 使用单独类处理 ##

@GetMapping("/test-sentinel-resource")
        @SentinelResource(
                value = "test-sentinel-api",
                blockHandlerClass = TestControllerBlockHandlerClass.class,
        )
        public String testSentinelResource(@RequestParam(required = false) String a) { 
            if (StringUtils.isBlank(a)) { 
                throw new IllegalArgumentException("a cannot be blank.");
            }
            return a;
        }

*  限流或降级处理类

@Slf4j
    public class TestControllerBlockHandlerClass { 
        /** * 处理限流或者降级 * * @param a * @param e * @return */
        public static String block(String a, BlockException e) { 
            log.warn("限流，或者降级了 block", e);
            return "限流，或者降级了 block";
        }
    }

![vv][]

[SentinelResource]: https://blog.csdn.net/las723/article/details/101207046
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[vv]: /images/20221124/11a0b85e12254f0a85301819686b5775.png