多个 Filter 的 doOnSuccess、doOnError 和 doFinally 执行顺序

在 Spring Cloud Gateway 中，多个 Filter 组成链时，doOnSuccess、doOnError 和 doFinally 的执行顺序由 Filter 嵌套和 Reactor 行为决定

执行顺序

假设 Filter 链为 Filter1 -> Filter2 -> … -> FilterN -> 代理服务：

成功完成

示例（FilterA -> FilterB）：

  1. FilterB doOnSuccess
  2. FilterA doOnSuccess
  3. FilterA doFinally
  4. FilterB doFinally

错误完成

示例（FilterA -> FilterB）：

  1. FilterB doOnError
  2. FilterA doOnError
  3. FilterA doFinally
  4. FilterB doFinally

验证样例

public class MonoFilterChainTest {
    public static void main(String[] args) {
        testSuccessCase();
        testErrorCase();
    }

    static void testSuccessCase() {
        Mono<Void> proxy = Mono.empty()
            .doOnSuccess(v -> System.out.println("FilterB doOnSuccess"))
            .doFinally(s -> System.out.println("FilterB doFinally"))
            .doOnSuccess(v -> System.out.println("FilterA doOnSuccess"))
            .doFinally(s -> System.out.println("FilterA doFinally"));
        proxy.subscribe();
    }

    static void testErrorCase() {
        Mono<Void> proxy = Mono.error(new RuntimeException("Error"))
            .doOnError(e -> System.out.println("FilterB doOnError"))
            .doFinally(s -> System.out.println("FilterB doFinally"))
            .doOnError(e -> System.out.println("FilterA doOnError"))
            .doFinally(s -> System.out.println("FilterA doFinally"));
        proxy.subscribe();
    }
}

输出

总结