尽管在 pom 上具有 commons-httpclient 和 httpcomponents 依赖项，但在运行有效 jar（使用依赖项编译）时出现 NoClassDefFoundError

Question

我正在尝试通过使用 main 方法中的 selenium webdriver 来自动化一个简单的用户行为（不在测试范围内） 从编译器运行以下代码时，它可以工作！ 但是在几种情况下运行 jar 时 - 面临以下问题 （我在 Ubuntu 上运行，使用 java 7）

“线程“主”java.lang.NoClassDefFoundError 中的异常：org/apache/http/conn/HttpClientConnectionManager”

@日志 公共类 MainProgram {

public  WebDriver driver = new FirefoxDriver();

public static void main(String args[]) {
 //   Injector injector = Guice.createInjector(new WebModule());

    System.out.println("Browser will soon be opened");
    MainProgram mainProgram = new MainProgram();
    mainProgram.run();

}

public void run(){

    driver.get("http://www.google.co.il");
    WebElement lookFor = driver.findElement(By.name("q"));

    if(!lookFor.isDisplayed()){
        driver.close();
      log.log(Level.WARNING,"Failed!");
    };
    driver.close();

}

}

WebDriver 对 pom 的依赖：

    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-server</artifactId>
        <version>2.42.2</version>
    </dependency>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-java</artifactId>
        <version>2.42.2</version>
    </dependency>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-api</artifactId>
        <version>2.42.2</version>
    </dependency>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-firefox-driver</artifactId>
        <version>2.42.2</version>
    </dependency>

Case A

 when removed -commons-httpclient - received: HttpClientConnectionManager as follows:

<!--
        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.1</version>
        </dependency>-->

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.3.4</version>
          <!--  <scope>test</scope>-->
        </dependency>


Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/conn/HttpClientConnectionManager
    at org.openqa.selenium.remote.HttpCommandExecutor.<init>(HttpCommandExecutor.java:99)
    at org.openqa.selenium.remote.HttpCommandExecutor.<init>(HttpCommandExecutor.java:82)
    at org.openqa.selenium.firefox.internal.NewProfileExtensionConnection.start(NewProfileExtensionConnection.java:77)

-------------------------------------------------------------------------------------------------------------------------------------------
Case B

removed both commons-httpclient + httpcomponents received HttpClientConnectionManager:

<!--        &lt;!&ndash;
        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.1</version>
        </dependency>&ndash;&gt;

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.3.4</version>
          &lt;!&ndash;  <scope>test</scope>&ndash;&gt;
        </dependency>-->


liron@liron-Latitude-3330:~$ java -jar automatic-tests-4.0-SNAPSHOT-jar-with-dependencies.jar
Try
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/conn/HttpClientConnectionManager
    at org.openqa.selenium.remote.HttpCommandExecutor.<init>(HttpCommandExecutor.java:99)
    at org.openqa.selenium.remote.HttpCommandExecutor.<init>(HttpCommandExecutor.java:82)

---------------------------------------------------------------------------------------------------------------------------------------------

Case C
when both were added to pom - same HttpClientConnectionManager


liron@liron-Latitude-3330:~$ java -jar automatic-tests-4.0-SNAPSHOT-jar-with-dependencies.jar
Browser will soon be opened
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/conn/HttpClientConnectionManager
    at org.openqa.selenium.remote.HttpCommandExecutor.<init>(HttpCommandExecutor.java:99)
    at org.openqa.selenium.remote.HttpCommandExecutor.<init>(HttpCommandExecutor.java:82)
    at org.openqa.selenium.firefox.internal.NewProfileExtensionConnection.start(NewProfileExtensionConnection.java:77)


----------------------------------------------------------------------------------------------------------------------------------------------

Answer 1

昨晚我的 WebDriver 项目遇到了同样的问题，经过一番调试，发现它缺少以下依赖项。添加它们后，我没有再次遇到此异常。

   <dependency>
       <groupId>org.apache.httpcomponents</groupId>
       <artifactId>httpclient</artifactId>
       <version>4.3.5</version>
   </dependency>

Answer 2

您的 pom 依赖项中应该只需要 selenium-java。请参阅this graphic @ Selenium HQ，它解释了 Selenium 的各个部分是如何相关的。此外，Selenium 本身依赖于httpclient，您不需要显式定义它们。如果您确实对这些有正当需求，那么事情就会发生冲突，您需要使用exclusions 进行清理。

清理完 pom 后，您可以运行 mvn dependency:tree 来查看您的项目中发生了什么。

Answer 3

添加新的 google guava 对我有帮助：

<dependency>
   <groupId>com.google.guava</groupId>
   <artifactId>guava</artifactId>
   <version>21.0</version>
</dependency>

那是因为其他依赖可以下载旧的 guava 18 版本。
当然就像 testphreak 说的：org.apache.httpcomponents