java.lang.IllegalArgumentException:名为[X]和[Y]的servlet都映射到不允许的url-pattern [/ url]

Question

我试着添加这个servlet

package com.classmgt.servlet;

@WebServlet("/ControllerServlet")
public class ControllerServlet extends HttpServlet {}

到我的Eclipse项目,通过编辑web.xml如下

<servlet>
    <description>Servlet to print out Hello World!</description>
    <display-name>ControllerServlet</display-name>
    <servlet-name>ControllerServlet</servlet-name>
    <servlet-class>com.classmgt.servlet.ControllerServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>ControllerServlet</servlet-name>
    <url-pattern>/ControllerServlet</url-pattern>
</servlet-mapping>

但是,我得到以下异常:

SEVERE: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/ClassManagementSystem]]
    at java.util.concurrent.FutureTask$Sync.innerGet(Unknown Source)
    at java.util.concurrent.FutureTask.get(Unknown Source)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:800)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/ClassManagementSystem]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
    ... 7 more
Caused by: java.lang.IllegalArgumentException: The servlets named [ControllerServlet] and [com.classmgt.servlet.ControllerServlet] are both mapped to the url-pattern [/ControllerServlet] which is not permitted
    at org.apache.catalina.deploy.WebXml.addServletMapping(WebXml.java:335)
    at org.apache.catalina.startup.ContextConfig.processAnnotationWebServlet(ContextConfig.java:2457)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:2139)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:2100)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:2093)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:2093)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:2093)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1300)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:878)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:369)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5269)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 7 more

我曾尝试添加metadata-complete="true"到web.xml,但现在不承认这个servlet.

Answer 1

引起:java.lang.IllegalArgumentException:名为[ControllerServlet]和[com.classmgt.servlet.ControllerServlet]的servlet都映射到url-pattern [/ ControllerServlet],这是不允许的

您似乎已经混合了@WebServlet基于注释和web.xml基于配置.

我怀疑你是否使用"Create Servlet"向导创建了一个Servlet,该向导使用url-pattern创建web.xml条目,然后添加了一个@WebServlet注释,该注释会复制您在web.xml中放置的任何内容.

你应该使用其中一个,而不是两个.从中删除映射web.xml并继续仅使用@WebServlet注释.

阅读更多:Servlet 3.0注释和我们的Servlets维基页面.

Answer 2

只需删除注释@WebServlet("/ControllerServlet"),ControllerServlet因为它已添加到web.xml.