java.lang.NoClassDefFoundError: gherkin/IGherkinDialectProvider 在运行 Selenium-Cucumber 测试时

Question

在我开始之前，我已经问了一个类似的问题here 并且当时的答案（更改“小黄瓜”版本）为我解决了这个问题。但是这次我使用 pom.xml 而不是 jars，并且使用较新的版本我无法纠正错误。另外，我问这个问题是为了缩小和了解根本原因，并防止将来出现类似的错误。

JUnit 代码：

package TestRunner;

import org.junit.runner.RunWith;

import cucumber.api.CucumberOptions;
import cucumber.api.junit.Cucumber;

@RunWith(Cucumber.class)                
@CucumberOptions(features="Features/S1Test.Feature",glue={"StepDefinition"})                        
public class Runner                 
{       

}

pom.xml

<project
 xmlns="http://maven.apache.org/POM/4.0.0"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <groupId>S1</groupId>
 <artifactId>S1</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <name>Load Testing</name>
 <description>Selenium Load Testing Example Using TestNG and Maven</description>

 <!-- Add Following Lines in Your POM File -->
 <properties>
  <selenium.version>2.53.1</selenium.version>
  <testng.version>6.9.10</testng.version>
 </properties>

 <dependencies>
        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-java</artifactId>
            <version>3.141.59</version>
        </dependency>
        <dependency>
            <groupId>io.cucumber</groupId>
            <artifactId>cucumber-core</artifactId>
            <version>4.2.6</version>
        </dependency>
        <dependency>
            <groupId>io.cucumber</groupId>
            <artifactId>cucumber-html</artifactId>
            <version>0.2.7</version>
        </dependency>
        <dependency>
            <groupId>net.sourceforge.cobertura</groupId>
            <artifactId>cobertura</artifactId>
            <version>2.1.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.cucumber</groupId>
            <artifactId>cucumber-java</artifactId>
            <version>4.2.6</version>
        </dependency>
        <dependency>
            <groupId>io.cucumber</groupId>
            <artifactId>cucumber-junit</artifactId>
            <version>4.2.6</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.cucumber</groupId>
            <artifactId>cucumber-jvm-deps</artifactId>
            <version>1.0.6</version>
            <!-- <scope>provided</scope> -->
        </dependency>
        <dependency>
            <groupId>net.masterthought</groupId>
            <artifactId>cucumber-reporting</artifactId>
            <version>4.5.1</version>
        </dependency>
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-core</artifactId>
            <version>2.21.0</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.cucumber</groupId>
            <artifactId>gherkin</artifactId>
            <version>6.0.17</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.sun</groupId>
            <artifactId>tools</artifactId>
            <version>1.6</version>
            <scope>system</scope>
            <systemPath>C:\Program Files\Java\jdk1.8.0_111\lib\tools.jar</systemPath>
        </dependency>
        <dependency>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-library</artifactId>
            <version>2.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <version>5.4.1</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

例外

java.lang.NoClassDefFoundError: gherkin/IGherkinDialectProvider
    at cucumber.runtime.RuntimeOptionsFactory.create(RuntimeOptionsFactory.java:23)
    at cucumber.api.junit.Cucumber.<init>(Cucumber.java:83)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
    at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createUnfilteredTest(JUnit4TestLoader.java:87)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:73)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:46)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:523)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:761)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:461)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:207)
Caused by: java.lang.ClassNotFoundException: gherkin.IGherkinDialectProvider
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 19 more

请帮助我了解为什么我会收到此异常，以及如何在未来使用更新版本避免此类错误。

Answer 1

Maven 依赖有两种类型：

• 直接：这些是在pom.xml 文件中<dependencies/> 部分下定义的依赖项。

• 传递性：这些是您的直接依赖关系的依赖关系。

重点：我们不会混合直接依赖和传递依赖，特别是它们的版本！这样做可能会导致不可预测的结果。

解决方法：请删除cucumber-core、cucumber-java、cucumber-jvm-deps、小黄瓜和Junit。它们是传递依赖项，将由您的依赖项提供。

您可以添加以下一组黄瓜最小依赖项。

<dependency>
    <groupId>io.cucumber</groupId>
    <artifactId>cucumber-junit</artifactId>
    <version>4.2.6</version>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>io.cucumber</groupId>
    <artifactId>cucumber-picocontainer</artifactId>
    <version>4.2.6</version>
    <scope>test</scope>
</dependency>

要了解更多信息，您可以启动 IDE，比如说 eclipse 并打开 pom.xml -> 转到选项卡，依赖层次结构。现在探索和学习！！

Answer 2

删除或注释掉

<dependency>
        <groupId>io.cucumber</groupId>
        <artifactId>gherkin</artifactId>
        <version>6.0.17</version>
    </dependency>

来自你的 pom 文件。它会起作用的。

Answer 3

您已将传递依赖项（您的依赖项的依赖项）添加到您的 pom.xml 中。这些应该与您的依赖项所需的版本相同。否则你会看到像你现在看到的那样的问题。

所以你应该删除：cucumber-jvm-deps、cucumber-core 和 gherkin。 Maven 将确保它们存在并具有正确的版本。

您可以使用mvn dependency:tree -Dverbose 检查您的依赖关系树。见 Apache Maven Dependency Plugin - Resolving conflicts using the dependency tree。