fallback顧名思義當(dāng)Java程序運(yùn)行發(fā)生錯(cuò)誤時(shí)，由該參數(shù)定義的方法進(jìn)行處理

@GetMapping(value = "/consumer/{id}")@SentinelResource(value = "consumer", fallback = "handlerFallback")public ResponseEntity<String> consumerData(@PathVariable("id")Integer id) {ResponseEntity<String> entity = remoteService.getData(id);if (id <= 0) {throw new IllegalArgumentException("非法參數(shù)異常!");} else if (entity.getData() == null) {throw new NullPointerException("無響應(yīng)數(shù)據(jù)，空指針異常!");}return entity;}public ResponseEntity<String> handlerFallback(Integer id, Throwable e) {return new ResponseEntity<>(443, "程序處理異常，開始執(zhí)行fallback數(shù)據(jù)-->" +e.getMessage());}

blockHandler這個(gè)也很好明白，也就是當(dāng)API違背控制臺(tái)設(shè)置的閾值時(shí)，執(zhí)行該參數(shù)定義的方法進(jìn)行處理；說白了就是限流之后的處理

@GetMapping(value = "/consumer/{id}")@SentinelResource(value = "consumer",blockHandler = "blockHandler")public ResponseEntity<String> consumerData(@PathVariable("id")Integer id) {ResponseEntity<String> entity = remoteService.getData(id);if (id <= 0) {throw new IllegalArgumentException("非法參數(shù)異常!");} else if (entity.getData() == null) {throw new NullPointerException("無響應(yīng)數(shù)據(jù)，空指針異常!");}return entity;}public ResponseEntity<String> blockHandler(BlockException blockException) {return new ResponseEntity<>(444, "QPS過高，服務(wù)開始熔斷降級(jí)--->"+blockException.getMessage());}

那么問題來了，如果同時(shí)發(fā)生Java運(yùn)行錯(cuò)誤和限流，那么會(huì)走哪個(gè)默認(rèn)的方法呢？

@GetMapping(value = "/consumer/{id}")@SentinelResource(value = "consumer", fallback = "handlerFallback", blockHandler = "blockHandler")public ResponseEntity<String> consumerData(@PathVariable("id")Integer id) {ResponseEntity<String> entity = remoteService.getData(id);if (id <= 0) {throw new IllegalArgumentException("非法參數(shù)異常!");} else if (entity.getData() == null) {throw new NullPointerException("無響應(yīng)數(shù)據(jù)，空指針異常!");}return entity;}public ResponseEntity<String> handlerFallback(Integer id, Throwable e) {return new ResponseEntity<>(443, "程序處理異常，開始執(zhí)行fallback數(shù)據(jù)-->" +e.getMessage());}public ResponseEntity<String> blockHandler(Integer id, BlockException blockException) {return new ResponseEntity<>(444, "QPS過高，服務(wù)開始熔斷降級(jí)--->"+blockException.getMessage());}

設(shè)置限流規(guī)則

當(dāng)我持續(xù)刷新，它走的是blockHandler路線

記得在配置文件加入以下

feign:sentinel:enabled: true

總結(jié)

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