Maven包错误：org.apache.commons-lang不存在（Java） [英] Maven package error: org.apache.commons-lang does not exist (Java)

问题描述

我正在使用MyEclipse开发一个非常简单的Java Struts项目。一切正常，直到我想在 org.apache.commons.lang 中使用 StringUtils 类。在MyEclipse中，我导入了包，如

I'm using MyEclipse to develop a really simple Java Struts project. Everything was working fine until I wanted to use the StringUtils class in org.apache.commons.lang. In MyEclipse I imported the package like

import org.apache.commons.lang.StringUtils;

我将 commons-lang-2.4 的Jar文件添加到我的构建中路径。这一切都很好，花花公子，我得到了Intellisense，没有Eclipse或任何错误。现在，当我去做一个 mvn clean package 时，我得到一个错误，说明

I added the Jar file for commons-lang-2.4 to my build path. This all works fine and dandy and I get the Intellisense and no errors in Eclipse or anything. Now, when I go to do a mvn clean package, I get an error saying that

包org.apache.commons.lang不存在

The package org.apache.commons.lang does not exist

我在war / Pom.xml文件中检查了我将它声明为依赖

I checked in my war/Pom.xml file and I do have it declared as a dependency

<dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.0.1</version>
    </dependency>

    <dependency>
        <groupId>commons-lang</groupId>
        <artifactId>commons-lang</artifactId>
        <version>2.4</version>
    </dependency>

</dependencies>

从我的研究中我发现Maven应该下载该软件包并将其安装到我的本地存储库（如果它不存在）。我检查了存储库，jar文件就在那里。我认为jar文件必须已损坏所以我删除了 commons-lang 文件夹以获得commons-lang的全新下载。现在这是我的想法，在我从本地存储库中删除它并运行 mvn clean package 之后，它就会出去并下载 commons-lang- 2.1 .pom和jar（即使pom.xml有2.4） BUT 仍然会出现编译失败，说包org.apache.commons.lang不存在的。

From my research I figured that Maven should download the package and install it to my local repository if it doesn't exists. I checked the repository and the jar file was in there. I figured the jar file must be corrupted so I deleted the commons-lang folder to get a fresh download of commons-lang. Now this is where it blows my mind, after I deleted it from the local repository and ran a mvn clean package, it goes out and downloads the commons-lang-2.1.pom and jar (even though the pom.xml has 2.4) BUT still gives a compilation failure saying that the package org.apache.commons.lang does not exist.

我没有使用Maven很长时间，所以我不确定如何解决这个问题。我错过了什么吗？我是否需要在其他地方的另一个pom.xml文件中添加依赖项？

I haven't been using Maven for very long so I'm not sure how to go about fixing this. Am I missing something? Do I need to add the dependency in another pom.xml file somewhere else?

推荐答案

尝试运行以下命令并检查输出：

Try running the following commands and examine the output:

$ mvn dependency:tree
$ mvn help:effective-pom

寻找 commons-lang ，也许某些事情会引起你的注意，例如排除或依赖性覆盖。另外，是：

Look for commons-lang, maybe something will draw your attention like excludes or dependency overrides. Also, is:

$ mvn dependency:copy-dependencies

将 commons-lang JAR复制到目标？

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