Tomcat Maven Plugin重新部署返回404错误的原因是什么？

Let's break down why you're hitting this 404 error with the tomcat7:redeploy goal and how to fix it.

Core Issue #

The tomcat7:redeploy goal depends entirely on Tomcat's Manager application to handle deployment operations. When you run mvn tomcat7:run, you're starting an embedded Tomcat instance—and by default, this embedded setup does NOT include the Manager application. That’s why you can’t access http://localhost:8080/manager, and why the redeploy call fails with a 404 when trying to reach /manager/text/deploy.

Solution 1: Use a Standalone Tomcat Installation (Recommended for Deployment Workflows) #

If you want to use redeploy reliably, it’s better to work with a standalone Tomcat instance instead of the embedded one:

1. Install and start standalone Tomcat 7
   Download Tomcat 7, extract it, and launch it using bin/startup.sh (Linux/macOS) or bin/startup.bat (Windows).

2. Configure user permissions for Manager access
   Edit conf/tomcat-users.xml in your standalone Tomcat directory to add a user with the manager-script role (required for the Maven plugin to interact with Manager):

   <tomcat-users>
     <!-- Keep existing users if any, add this entry -->
     <user username="tomcat" password="tomcat" roles="manager-script,manager-gui"/>
   </tomcat-users>
   

   Restart Tomcat to apply this change.

3. Update your pom.xml plugin configuration
   Point the plugin to your standalone Tomcat’s Manager text interface:

   <plugin>
     <groupId>org.apache.tomcat.maven</groupId>
     <artifactId>tomcat7-maven-plugin</artifactId>
     <version>2.2</version>
     <configuration>
       <!-- URL of standalone Tomcat's Manager text endpoint -->
       <url>http://localhost:8080/manager/text</url>
       <!-- Reference to a server entry in your Maven settings -->
       <server>TomcatStandalone</server>
       <!-- Context path for your application -->
       <path>/app</path>
     </configuration>
   </plugin>
   

4. Add server credentials to Maven settings.xml
   Open your Maven settings.xml (usually located at ~/.m2/settings.xml or conf/settings.xml in your Maven installation) and add a server entry matching the <server> value above:

   <servers>
     <server>
       <id>TomcatStandalone</id>
       <username>tomcat</username>
       <password>tomcat</password>
     </server>
   </servers>
   

5. Run the redeploy command
   Stop any running embedded Tomcat instances, start your standalone Tomcat, then execute:

   mvn package tomcat7:redeploy
   

   This should work now, as the plugin is communicating with the fully functional Manager app in your standalone Tomcat.

Solution 2: Enable Manager in the Embedded Tomcat (For Testing Only) #

If you need to use the embedded Tomcat with redeploy (not recommended for production), you can force it to include the Manager app:

1. Update pom.xml to include the Manager dependency
   Modify your plugin configuration to add the Tomcat Manager WAR as an additional dependency:

   <plugin>
     <groupId>org.apache.tomcat.maven</groupId>
     <artifactId>tomcat7-maven-plugin</artifactId>
     <version>2.2</version>
     <configuration>
       <server>TomcatEmbedded</server>
       <path>/app</path>
       <additionalDependencies>
         <additionalDependency>
           <groupId>org.apache.tomcat</groupId>
           <artifactId>tomcat-manager</artifactId>
           <version>7.0.55</version> <!-- Matches the Tomcat version used by plugin 2.2 -->
           <type>war</type>
         </additionalDependency>
       </additionalDependencies>
       <!-- Configure embedded Tomcat users -->
       <tomcatUsers>
         <user username="admin" password="admin" roles="manager-script"/>
       </tomcatUsers>
     </configuration>
   </plugin>
   

2. Add server credentials to Maven settings.xml
   Add a server entry for TomcatEmbedded using the username/password you set in the plugin configuration.

3. Test the setup
   Start the embedded Tomcat with mvn tomcat7:run, then in a separate terminal run mvn package tomcat7:redeploy. You should now be able to access http://localhost:8080/manager/html (note the /html suffix) and the redeploy should succeed.

Quick Verification Step #

Before running redeploy, always confirm the Manager app is accessible:

• For standalone Tomcat: Visit http://localhost:8080/manager and log in with your configured user.
• For embedded Tomcat: Visit http://localhost:8080/manager/html and log in.

If the Manager loads without issues, your redeploy command should work without 404 errors.

内容的提问来源于stack exchange，提问作者marcioggs