生命不息，奋斗不止。——卡莱尔
分享一个小技巧，在webflux开发中，我们可以在主启动类上加这么一行代码：
Hooks.onOperatorDebug();
这行代码的用处是注册一个回调函数，可以打印操作符信息，举个例子：
import reactor.core.publisher.Flux; import reactor.core.publisher.Hooks; public class DebugExample { public static void main(String[] args) { Hooks.onOperatorDebug(); // 启用操作符调试 Flux<Integer> flux = Flux.just(1, 2, 3, 4) .map(i -> i / 0); // 这里会触发除以零的异常 flux.subscribe( value -> System.out.println("Received: " + value), error -> System.err.println("Error: " + error) ); } }
如果我们没有注册，则堆栈打印信息：
Received: 1 Received: 2 Received: 3 Exception in thread "main" java.lang.ArithmeticException: / by zero at DebugExample.lambda$main$0(DebugExample.java:12) at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:120) at reactor.core.publisher.FluxJust$WeakScalarSubscription.request(FluxJust.java:91) at reactor.core.publisher.FluxMap$MapSubscriber.request(FluxMap.java:155) at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:1266) at reactor.core.publisher.FluxMap.onSubscribe(FluxMap.java:59) at reactor.core.publisher.FluxJust.subscribe(FluxJust.java:68) at reactor.core.publisher.FluxMap.subscribe(FluxMap.java:44) at reactor.core.publisher.Flux.subscribe(Flux.java:9117) at reactor.core.publisher.Flux.subscribe(Flux.java:9091) at DebugExample.main(DebugExample.java:14)
注册以后：
Received: 1 Received: 2 Received: 3 Error: java.lang.ArithmeticException: / by zero at reactor.core.publisher.Operators.onErrorDropped(Operators.java:197) Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: | onSubscribe([Synchronous Fuseable] FluxMapFuseable.MapFuseableSubscriber) | Flux.map(Map.java:95) | Flux.map(Map.java:92) | DebugExample.main(DebugExample.java:15) | onAssembly(FluxMapFuseable) | Flux.map(Map.java:95) | Flux.map(Map.java:92) | DebugExample.main(DebugExample.java:15) | request(unbounded) at reactor.core.publisher.FluxOnAssembly.onAssembly(FluxOnAssembly.java:482) at reactor.core.publisher.FluxMapFuseable.subscribe(FluxMapFuseable.java:64) at reactor.core.publisher.Flux.subscribe(Flux.java:9065) at reactor.core.publisher.Flux.subscribe(Flux.java:9039) at DebugExample.main(DebugExample.java:14) Suppressed: java.lang.ArithmeticException: / by zero at reactor.core.publisher.Operators.onErrorDropped(Operators.java:197) Suppressed: java.lang.ArithmeticException: / by zero at reactor.core.publisher.Operators.onErrorDropped(Operators.java:197) Suppressed: java.lang.ArithmeticException: / by zero at reactor.core.publisher.Operators.onErrorDropped(Operators.java:197) Suppressed: java.lang.ArithmeticException: / by zero at reactor.core.publisher.Operators.onErrorDropped(Operators.java:197) Suppressed: java.lang.ArithmeticException: / by zero at reactor.core.publisher.Operators.onErrorDropped(Operators.java:197) Suppressed: java.lang.ArithmeticException: / by zero at reactor.core.publisher.Operators.onErrorDropped(Operators.java:197) Suppressed: java.lang.ArithmeticException: / by zero at reactor.core.publisher.Operators.onErrorDropped(Operators.java:197) Suppressed: java.lang.ArithmeticException: / by zero at reactor.core.publisher.Operators.onErrorDropped(Operators.java:197) at reactor.core.publisher.FluxOnAssembly.onAssembly(FluxOnAssembly.java:482) at reactor.core.publisher.FluxMapFuseable.subscribe(FluxMapFuseable.java:64) at reactor.core.publisher.Flux.subscribe(Flux.java:9065) at reactor.core.publisher.Flux.subscribe(Flux.java:9039) at DebugExample.main(DebugExample.java:14)
