使用Maven插件`tomcat7-maven-plugin`部署web应用时出现401 Unauthorized错误

问题描述

在使用Maven插件tomcat7-maven-plugin自动部署web应用到Tomcat时，遇到了401 Unauthorized错误。他已经按照以下三个步骤进行了操作：
1. 在Tomcat的安装目录下的conf\tomcat-users.xml文件中添加了一个具有部署权限的新用户。
2. 在Maven的conf\settings.xml文件中的servers节点中添加了上述Tomcat用户的信息。
3. 在项目的pom.xml文件中添加了使用tomcat7-maven-plugin插件的配置。

在第一步中，用户在conf\tomcat-users.xml文件中添加了以下内容：

 <role rolename="manager-gui"/>
<role rolename="manager-script"/>
<role rolename="manager-jmx"/>
<user username="war-deployer" password="some-password" roles="manager-gui,manager-script,manager-jmx" />

然后，用户重启了Tomcat。

在第二步中，用户在conf\settings.xml文件的servers节点中添加了以下内容：

 <server>
    <id>maven-tomcat-war-deployment-server</id>
    <username>war-deployer</username>
    <password>some-password</password>
</server>

最后，在第三步中，用户在项目的pom.xml文件的plugins节点中添加了以下内容，以使用tomcat7-maven-plugin插件：

 <plugin>
    <groupId>org.apache.tomcat.maven</groupId>
    <artifactId>tomcat7-maven-plugin</artifactId>
    <version>2.0</version>
    <configuration>
        <url>http://localhost:8080/manager/text</url>
        <path>/my-project-url-path</path>
    </configuration>
</plugin>

用户以为一切都会顺利进行，但是当执行命令mvn tomcat7:deploy时，他的web应用没有被部署，Tomcat的webapps目录中没有任何内容，并且Tomcat返回了以下响应：

[INFO] tomcatManager status code:401, ReasonPhrase:[INFO] <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">[INFO] <html>[INFO]  <head>[INFO]   <title>401 Unauthorized</title>[INFO]   <style type="text/css">[INFO]     <!--[INFO]     BODY {font-family:Tahoma,Arial,sans-serif;color:black;background-color:white;font-size:12px;}[INFO]     H1 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:22px;}[INFO]     PRE, TT {border: 1px dotted #525D76}[INFO]     A {color : black;}A.name {color : black;}[INFO]     -->[INFO]   </style>[INFO]  </head>[INFO]  <body>[INFO]    <h1>401 Unauthorized</h1>[INFO]    <p>[INFO]     You are not authorized to view this page. If you have not changed[INFO]     any configuration files, please examine the file[INFO]     <tt>conf/tomcat-users.xml</tt> in your installation. That[INFO]     file must contain the credentials to let you use this webapp.[INFO]    </p>[INFO]    <p>[INFO]     For example, to add the <tt>manager-gui</tt> role to a user named[INFO]     <tt>tomcat</tt> with a password of <tt>s3cret</tt>, add the following to the[INFO]     config file listed above.[INFO]    </p>[INFO] <pre>[INFO] &lt;role rolename="manager-gui"/&gt;[INFO] &lt;user username="tomcat" password="s3cret" roles="manager-gui"/&gt;[INFO] </pre>[INFO]    <p>[INFO]     Note that for Tomcat 7 onwards, the roles required to use the manager[INFO]     application were changed from the single <tt>manager</tt> role to the[INFO]     following four roles. You will need to assign the role(s) required for[INFO]     the functionality you wish to access.[INFO]    </p>[INFO]     <ul>[INFO]       <li><tt>manager-gui</tt> - allows access to the HTML GUI and the status[INFO]           pages</li>[INFO]       <li><tt>manager-script</tt> - allows access to the text interface and the[INFO]           status pages</li>[INFO]       <li><tt>manager-jmx</tt> - allows access to the JMX proxy and the status[INFO]           pages</li>[INFO]       <li><tt>manager-status</tt> - allows access to the status pages only</li>[INFO]     </ul>[INFO]    <p>[INFO]     The HTML interface is protected against CSRF but the text and JMX interfaces[INFO]     are not. To maintain the CSRF protection:[INFO]    </p>[INFO]    <ul>[INFO]     <li>Users with the <tt>manager-gui</tt> role should not be granted either[INFO]         the <tt>manager-script</tt> or <tt>manager-jmx</tt> roles.</li>[INFO]     <li>If the text or jmx interfaces are accessed through a browser (e.g. for[INFO]         testing since these interfaces are intended for tools not humans) then[INFO]         the browser must be closed afterwards to terminate the session.</li>[INFO]    </ul>[INFO]    <p>[INFO]     For more information - please see the[INFO]     <a href="/docs/manager-howto.html" rel="noopener noreferrer">Manager App How-To</a>.[INFO]    </p>[INFO]  </body>[INFO] </html>

尽管Maven没有报告任何错误，并且最后显示了BUILD SUCCESS，但用户已经为此问题苦苦挣扎了几个小时，并且在网上搜索了很多，但是找不到解决办法。请帮助用户解决这个问题。非常感谢！

解决方案

请注意以下操作注意版本差异及修改前做好备份。

方案

问题出现的原因是你忘记将插件的<configuration>与settings.xml中的<server>定义关联起来，因此tomcat7-maven-plugin尝试以未经身份验证的方式进行部署。

你需要在插件的配置部分添加<server>maven-tomcat-war-deployment-server</server>，如下所示：

 <configuration>
    <server>maven-tomcat-war-deployment-server</server>
    <url>http://localhost:8080/manager/text</url>
    <path>/my-project-url-path</path>
</configuration>

这样，插件就会使用settings.xml中定义的服务器信息进行身份验证，从而解决401 Unauthorized错误。

请注意，确保<server>的<id>与pom.xml中的插件配置中的<server>一致。

希望这个解决方案能帮助到你。如果还有其他问题，请随时提问。

	<role rolename="manager-gui"/>
	<role rolename="manager-script"/>
	<role rolename="manager-jmx"/>
	<user username="war-deployer" password="some-password" roles="manager-gui,manager-script,manager-jmx" />

	<server>
	<id>maven-tomcat-war-deployment-server</id>
	<username>war-deployer</username>
	<password>some-password</password>
	</server>

	<plugin>
	<groupId>org.apache.tomcat.maven</groupId>
	<artifactId>tomcat7-maven-plugin</artifactId>
	<version>2.0</version>
	<configuration>
	<url>http://localhost:8080/manager/text</url>
	<path>/my-project-url-path</path>
	</configuration>
	</plugin>

	<configuration>
	<server>maven-tomcat-war-deployment-server</server>
	<url>http://localhost:8080/manager/text</url>
	<path>/my-project-url-path</path>
	</configuration>