Tomcat 上的 Wicket 快速入门：Servlet NoSuchMethodError答案

【问题标题】：Wicket Quickstart on Tomcat: Servlet NoSuchMethodErrorTomcat 上的 Wicket 快速入门：Servlet NoSuchMethodError
【发布时间】：2015-10-06 05:47:24
【问题描述】：

Wicket 和 Java Web 开发新手。我从 Wicket 网站获得了一个快速入门项目，我正在尝试在本地 Tomcat 服务器上运行它。主页目前给我一个错误：“javax.servlet.ServletException：过滤器执行引发异常”。

这是堆栈跟踪：

Oct 05, 2015 10:40:18 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet default threw exception
java.lang.NoSuchMethodError: javax.servlet.http.HttpServletRequest.isAsyncStarted()Z
at org.apache.wicket.protocol.http.servlet.ServletWebResponse.flush(ServletWebResponse.java:319)
at org.apache.wicket.protocol.http.HeaderBufferingWebResponse.flush(HeaderBufferingWebResponse.java:99)
at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:263)
at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:203)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:284)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:745)

我已将 tomcat 8 库及其 servlet-api.jar 添加到我的类路径中。 pom.xml 或 web.xml 中似乎没有任何关于 servlet 的内容。我读过它可能是 servlet-api 版本问题，但 mvn install 似乎正在安装正确的版本（3.1.0）。这是 pom.xml 文件：

<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License.  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

<modelVersion>4.0.0</modelVersion>
<groupId>com.drat.proteus</groupId>
<artifactId>proteus</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
    <!-- TODO project name  -->
<name>quickstart</name>
<description></description>
<!--
    <organization>
        <name>company name</name>
        <url>company url</url>
    </organization>
-->
<licenses>
    <license>
        <name>The Apache Software License, Version 2.0</name>
        <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
        <distribution>repo</distribution>
    </license>
</licenses>
<properties>
    <wicket.version>7.0.0</wicket.version>
    <jetty9.version>9.2.11.v20150529</jetty9.version>
    <log4j.version>2.3</log4j.version>
    <junit.version>4.12</junit.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <!-- allowed values: R7, 1.0, 1.5, 2.0 or none -->
    <wtp.version>none</wtp.version>
</properties>
<dependencies>
    <!--  WICKET DEPENDENCIES -->
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-core</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <!-- OPTIONAL DEPENDENCY
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-extensions</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    -->

    <!-- LOGGING DEPENDENCIES - LOG4J -->
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-slf4j-impl</artifactId>
        <version>${log4j.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-core</artifactId>
        <version>${log4j.version}</version>
    </dependency>

    <!--  JUNIT DEPENDENCY FOR TESTING -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>${junit.version}</version>
        <scope>test</scope>
    </dependency>

    <!--  JETTY DEPENDENCIES FOR TESTING  -->
    <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-server</artifactId>
        <version>${jetty9.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-webapp</artifactId>
        <version>${jetty9.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-util</artifactId>
        <version>${jetty9.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-jmx</artifactId>
        <version>${jetty9.version}</version>
        <scope>test</scope>
    </dependency>
</dependencies>
<build>
    <resources>
        <resource>
            <filtering>false</filtering>
            <directory>src/main/resources</directory>
        </resource>
        <resource>
            <filtering>false</filtering>
            <directory>src/main/java</directory>
            <includes>
                <include>**</include>
            </includes>
            <excludes>
                <exclude>**/*.java</exclude>
            </excludes>
        </resource>
    </resources>
    <testResources>
        <testResource>
            <filtering>false</filtering>
            <directory>src/test/resources</directory>
        </testResource>
        <testResource>
            <filtering>false</filtering>
            <directory>src/test/java</directory>
            <includes>
                <include>**</include>
            </includes>
            <excludes>
                <exclude>**/*.java</exclude>
            </excludes>
        </testResource>
    </testResources>
    <plugins>
        <plugin>
            <inherited>true</inherited>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
                <encoding>UTF-8</encoding>
                <showWarnings>true</showWarnings>
                <showDeprecation>true</showDeprecation>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-maven-plugin</artifactId>
            <version>${jetty9.version}</version>
            <configuration>
                <systemProperties>
                    <systemProperty>
                        <name>maven.project.build.directory.test-classes</name>
                        <value>${project.build.directory}/test-classes</value>
                    </systemProperty>
                </systemProperties>
                <jettyXml>${project.basedir}/src/test/jetty/jetty.xml,${project.basedir}/src/test/jetty/jetty-ssl.xml,${project.basedir}/src/test/jetty/jetty-http.xml,${project.basedir}/src/test/jetty/jetty-https.xml</jettyXml>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-eclipse-plugin</artifactId>
            <version>2.9</version>
            <configuration>
                <downloadSources>true</downloadSources>
                <wtpversion>${wtp.version}</wtpversion>
            </configuration>
        </plugin>
    </plugins>
</build>

<repositories>
    <repository>
        <id>Apache Nexus</id>
        <url>https://repository.apache.org/content/repositories/snapshots/</url>
        <releases>
            <enabled>false</enabled>
        </releases>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </repository>
</repositories>
</project>

谢谢！

【问题讨论】：

方法isAsyncStarted从servlet-api 3.0开始就存在了，看docs.oracle.com/javaee/6/api/javax/servlet/…你用的是哪个servlet API？
@MartinStrejc 当我进行 mvn 安装时，servlet-api 的所有实例都是 3.1.0 但是，就像我说的，pom.xml 中没有提到 servlet，所以我不确定在哪里那是来自。我已将 pom 文件添加到我的帖子中。
POM 中的 Maven 依赖项具有“已提供”范围。这意味着它可以从代码中访问，它是用那个库编译的，但它不是最终战争的一部分。原因是 JAR 库应该是共享目录（例如 libs）中服务器（例如 Tomcat）的一部分。见github.com/apache/wicket/blob/master/pom.xml

标签： tomcat wicket

【解决方案1】：

将web.xml中的版本改成3.0，现在还是2.5

来自：

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" 
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
      http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
      version="2.5">
...
</web-app>

到：

<web-app xmlns="http://java.sun.com/xml/ns/javaee"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
      http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
      version="3.0">
...
</web-app>

或：

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
     http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
     version="3.1">
...
</web-app>

也许这会有所帮助。

【讨论】：

谢谢！我已经修复了 Wicket 的快速入门 Maven 原型。
这样做并没有解决 servlet 问题。不过，这绝对是件好事。