无法调用“org.springframework.cloud.netflix.eureka.CloudEurekaClient.getApplications()”

Question

我将 Gradle 配置更新为最新的 Spring Cloud 版本和 Spring 版本：

plugins {
    id 'org.springframework.boot' version '2.5.5'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
}

group = 'com.test'
version = '0.0.1'
sourceCompatibility = '11'

repositories {
    mavenCentral()
}

ext {
    set('springCloudVersion', "2020.0.4")
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.cloud:spring-cloud-starter-openfeign'
    implementation 'org.springframework.cloud:spring-cloud-starter-loadbalancer'
    implementation 'com.netflix.eureka:eureka-core'
    implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
    implementation 'org.springframework.boot:spring-boot-starter-validation'
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation 'javax.validation:validation-api'
    implementation 'org.hibernate.validator:hibernate-validator'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    implementation 'org.threeten:threetenbp:1.5.1'
    implementation 'org.springframework.boot:spring-boot-starter-actuator'
    // Lombok
    compileOnly 'org.projectlombok:lombok:1.18.20'
    annotationProcessor 'org.projectlombok:lombok:1.18.20'
    testCompileOnly 'org.projectlombok:lombok:1.18.20'
    testAnnotationProcessor 'org.projectlombok:lombok:1.18.20'
    // Mapstruct
    implementation 'org.mapstruct:mapstruct:1.4.2.Final'
    annotationProcessor 'org.mapstruct:mapstruct-processor:1.4.2.Final'
    runtimeOnly 'org.postgresql:postgresql'
    // Swagger
    implementation group: 'io.springfox', name: 'springfox-swagger2', version: '3.0.0'
    implementation 'org.liquibase:liquibase-core'
}

dependencyManagement {
    imports {
        mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
    }
}

test {
    useJUnitPlatform()
}

但是当我启动应用程序时，我得到：

10:11:27.970 [main] ERROR SpringApplication[reportFailure:843] - Application run failed
org.springframework.context.ApplicationContextException: Failed to start bean 'eurekaAutoServiceRegistration'; nested exception is java.lang.NullPointerException: Cannot invoke "org.springframework.cloud.netflix.eureka.CloudEurekaClient.getApplications()" because the return value of "org.springframework.cloud.netflix.eureka.serviceregistry.EurekaRegistration.getEurekaClient()" is null
        at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181)
        at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54)
        at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356)
        at java.base/java.lang.Iterable.forEach(Iterable.java:75)
        at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155)
        at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123)
        at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586)
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754)
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:434)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:338)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1332)
        at org.MerchantHubApplication.main(MerchantHubApplication.java:18)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:567)
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:108)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:58)
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:88)
Caused by: java.lang.NullPointerException: Cannot invoke "org.springframework.cloud.netflix.eureka.CloudEurekaClient.getApplications()" because the return value of "org.springframework.cloud.netflix.eureka.serviceregistry.EurekaRegistration.getEurekaClient()" is null
        at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaServiceRegistry.maybeInitializeClient(EurekaServiceRegistry.java:54)
        at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaServiceRegistry.register(EurekaServiceRegistry.java:38)
        at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaAutoServiceRegistration.start(EurekaAutoServiceRegistration.java:83)
        at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178)
        ... 22 common frames omitted

application.yml配置：

eureka:
  client:
    serviceUrl:
      defaultZone: ${EUREKA_URI:http://localhost:8761/eureka}
    fetchRegistry: true
    healthcheck:
      enabled: true
  instance:
    preferIpAddress: true
    leaseRenewalIntervalInSeconds: 10

你知道可能是什么问题吗？

Answer 1

有时它会发生在 JRE 版本:

您的编译时 JDK 版本和运行时 JDK 版本可能不同。

如：编译时 JDK 11 和 运行时 JDK 17。

运行时 JRE 将与编译时相同。

Answer 2

你必须在 Gradle 配置中添加它，我现在不知道如何在你的 Gradle 配置中添加它，但我对 Maven 项目有同样的问题，我在 pom.xml 中添加了它

添加它时没有

<dependencyManagement>

我看到同样的问题

        <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>

但是添加以下配置后，我在尤里卡中运行项目和注册表，没有任何问题

<dependencyManagement>
<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>${spring-cloud.version}</version>
        <type>pom</type>
        <scope>import</scope>
    </dependency>

</dependencies>

我认为这个解决方案可以帮助你解决你的问题，但你必须将它从maven转换为Gradle

Answer 3

就我而言，版本

2.2.5.RELEASE

导致了错误。 因此，我尝试将其更改为如下所示的

3.1.3

，然后运行就没有任何问题了。

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    <version>3.1.3</version>
</dependency>

Answer 4

我在运行我的项目时遇到了同样的问题。如果您正在使用 IntellijIDE，您需要检查： File -> Project Structure -> Project：这里您需要检查您的 SDK 和 Language level 与 pom 文件中的 相同

Answer 5

我认为你的问题来自于你的 spring 版本与你的 spring boot 版本尝试将两者更新到以下版本

id 'org.springframework.boot' version '2.5.10-SNAPSHOT'


set('springCloudVersion', "2020.0.5")

Answer 6

从客户端添加此依赖项

    <dependency>
        <groupId>jakarta.servlet</groupId>
        <artifactId>jakarta.servlet-api</artifactId>
        <version>5.0.0</version><!--$NO-MVN-MAN-VER$-->
        <scope>provided</scope>
    </dependency>

• 您也可能在 Spring Boot 3X 版本中遇到这个问题