无法使用 Spring Cloud Hoxton SR4 在 Spring-Cloud-Gateway 中实例化 DiscoveryLocatorProperties

Question

感谢任何帮助解决以下问题。我正在使用 Spring Cloud Hoxton.SR4 并使用 spring-cloud-starter-gateway 创建了一个网关服务。应用程序在启动时抛出以下异常。

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'discoveryClientRouteDefinitionLocator' defined in class path resource [org/springframework/cloud/gateway/discovery/GatewayDiscoveryClientAutoConfiguration$ReactiveDiscoveryClientRouteDefinitionLocatorConfiguration.class]: Unsatisfied dependency expressed through method 'discoveryClientRouteDefinitionLocator' parameter 1; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'discoveryLocatorProperties' defined in class path resource [org/springframework/cloud/gateway/discovery/GatewayDiscoveryClientAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.gateway.discovery.DiscoveryLocatorProperties]: Factory method 'discoveryLocatorProperties' threw exception; nested exception is java.lang.NoClassDefFoundError: javax/validation/ValidationException
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:798) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:539) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1338) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.gateway.discovery.DiscoveryLocatorProperties]: Factory method 'discoveryLocatorProperties' threw exception; nested exception is java.lang.NoClassDefFoundError: javax/validation/ValidationException
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:651) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    ... 39 common frames omitted
Caused by: java.lang.NoClassDefFoundError: javax/validation/ValidationException
    at org.springframework.cloud.gateway.discovery.GatewayDiscoveryClientAutoConfiguration.initPredicates(GatewayDiscoveryClientAutoConfiguration.java:61) ~[spring-cloud-gateway-core-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.cloud.gateway.discovery.GatewayDiscoveryClientAutoConfiguration.discoveryLocatorProperties(GatewayDiscoveryClientAutoConfiguration.java:86) ~[spring-cloud-gateway-core-2.2.2.RELEASE.jar:2.2.2.RELEASE]enter code here
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_212]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_212]
    at sun.reflect.DelegatingMethodAccessorImpl.invoenter code hereke(Unknown Source) ~[na:1.8.0_212]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_212]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    ... 40 common frames omitted
Caused by: java.lang.ClassNotFoundException: javax.validation.ValidationException


   at java.net.URLClassLoader.findClass(Unknown Source) ~[na:1.8.0_212]
        at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_212]
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) ~[na:1.8.0_212]
        at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_212]
    ... 47 common frames omitted>

我也在 application.properties 中添加了以下条目；但它并没有解决问题

spring.cloud.gateway.discovery.locator.enabled=true
spring.cloud.gateway.discovery.locator.lower-case-service-id=true

Answer 1

看到这个：Spring Boot 2.3 Release Notes

上面写着：

从 #19550 开始，Web 和 WebFlux 启动器默认不再依赖验证启动器。如果您的应用程序正在使用验证功能，则需要在构建文件中手动添加对 spring-boot-starter-validation 的依赖。

Spring Initializr 似乎没有选择这个，所以现在每个人都缺少验证启动器。

将以下内容添加到您的 POM 中的 <dependencies> 块中：

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-validation</artifactId>
    </dependency>