Fix for Spring Boot 2.5.x + Zuul - NoSuchMethodError: ErrorController.getErrorPath()

ZuulConfiguration.java

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.boot.web.servlet.error.ErrorController;
import org.springframework.cglib.proxy.Callback;
import org.springframework.cglib.proxy.CallbackFilter;
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;
import org.springframework.cglib.proxy.NoOp;
import org.springframework.cloud.netflix.zuul.filters.RouteLocator;
import org.springframework.cloud.netflix.zuul.web.ZuulController;
import org.springframework.cloud.netflix.zuul.web.ZuulHandlerMapping;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/** Zuul configuration. */
@Configuration
public class ZuulConfiguration {

    /** The path returned by ErrorContoller.getErrorPath() with Spring Boot < 2.5 (and no longer available on Spring Boot >= 2.5). */
    private static final String ERROR_PATH = "/error";

    /**
     * Constructs a new bean post-processor for Zuul.
     * 
     * @param routeLocator
     *            the route locator.
     * @param zuulController
     *            the Zuul controller.
     * @param errorController
     *            the error controller.
     * @return the new bean post-processor.
     */
    @Bean
    public ZuulPostProcessor zuulPostProcessor(@Autowired RouteLocator routeLocator, @Autowired ZuulController zuulController,
            @Autowired(required = false) ErrorController errorController) {
        return new ZuulPostProcessor(routeLocator, zuulController, errorController);
    }

    private static final class ZuulPostProcessor implements BeanPostProcessor {

        private final RouteLocator routeLocator;

        private final ZuulController zuulController;

        private final boolean hasErrorController;

        ZuulPostProcessor(RouteLocator routeLocator, ZuulController zuulController, ErrorController errorController) {
            this.routeLocator = routeLocator;
            this.zuulController = zuulController;
            this.hasErrorController = (errorController != null);
        }

        @Override
        public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
            if (hasErrorController && (bean instanceof ZuulHandlerMapping)) {
                Enhancer enhancer = new Enhancer();
                enhancer.setSuperclass(ZuulHandlerMapping.class);
                enhancer.setCallbackFilter(LookupHandlerCallbackFilter.INSTANCE); // only for lookupHandler
                enhancer.setCallbacks(new Callback[] { LookupHandlerMethodInterceptor.INSTANCE, NoOp.INSTANCE });
                Constructor<?> ctor = ZuulHandlerMapping.class.getConstructors()[0];
                return enhancer.create(ctor.getParameterTypes(), new Object[] { routeLocator, zuulController });
            }
            return bean;
        }

    }

    private static enum LookupHandlerCallbackFilter implements CallbackFilter {

        INSTANCE;

        @Override
        public int accept(Method method) {
            if ("lookupHandler".equals(method.getName())) {
                return 0;
            }
            return 1;
        }

    }

    private static enum LookupHandlerMethodInterceptor implements MethodInterceptor {

        INSTANCE;

        @Override
        public Object intercept(Object target, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
            if (ERROR_PATH.equals(args[0])) {

                /* by entering this branch we avoid the ZuulHandlerMapping.lookupHandler method to trigger the NoSuchMethodError */
                return null;
            }
            return methodProxy.invokeSuper(target, args);
        }

    }

}

Seems to work in ver. 2.7.1 as well! - At least this very error is gone wink THANKS!

Hey! I'm a newbie to learn microservices using spring boot. Can anybody tell where to create this file? I'm getting error in the pom.xml itself. Using spring version 2.7.5

Hi I am trying to migrate a spring boot 2.4.4 and zuul 1.3.1 to 2.7.0 but its not working with 1.3.1 so I tried to upgarde to zuul 2.0.0 but now issue is In my Code RequestContext was used But now in zuul 2.0.0 Its not there Any Idea How to Fix it.

does this solution is working with spring boot 3.0.5