如何解决Tomcat 9出现java.lang.ClassNotFoundException: waffle.apache.MixedAuthenticator问题

使用Apache Tomcat 9运行Java项目，引入对应pom依赖后启动Tomcat服务器时出现报错，Apache Tomcat 7下未遇到该问题，切换到Tomcat 9后触发问题，报错指向lib文件夹下的apache tomcat util jar包。

使用的Pom文件如下 #

<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>AMS</groupId>
<artifactId>AMS</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<name>webservice_app</name>
<url>Welcome to Apache Maven</url>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.json/json -->
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20140107</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.slf4j/jcl-over-slf4j -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
<version>2.0.0-alpha1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.mail/mail -->
<dependency>
<groupId>javax.mail</groupId>
<artifactId>mail</artifactId>
<version>1.4.7</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.0.1</version>
<scope>provided</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/com.microsoft.sqlserver/mssql-jdbc -->
<dependency>
<groupId>com.microsoft.sqlserver</groupId>
<artifactId>mssql-jdbc</artifactId>
<version>9.4.0.jre16</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.github.waffle/waffle-jetty -->
<dependency>
<groupId>com.github.waffle</groupId>
<artifactId>waffle-jetty</artifactId>
<version>1.9.1</version>
<scope>runtime</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/com.github.waffle/waffle-shiro -->
<dependency>
<groupId>com.github.waffle</groupId>
<artifactId>waffle-shiro</artifactId>
<version>3.0.0</version>
<scope>runtime</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/com.github.waffle/waffle-spring-security4 -->
<dependency>
<groupId>com.github.waffle</groupId>
<artifactId>waffle-spring-security4</artifactId>
<version>1.8.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.webjars/jquery -->
<dependency>
<groupId>org.webjars</groupId>
<artifactId>jquery</artifactId>
<version>3.6.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.webjars/datatables -->
<dependency>
<groupId>org.webjars</groupId>
<artifactId>datatables</artifactId>
<version>1.11.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.google.guava/guava -->
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>31.0.1-jre</version>
</dependency>
<!-- https://mvnrepository.com/artifact/net.java.dev.jna/jna -->
<dependency>
<groupId>net.java.dev.jna</groupId>
<artifactId>jna</artifactId>
<version>5.10.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/net.java.dev.jna/jna-platform -->
<dependency>
<groupId>net.java.dev.jna</groupId>
<artifactId>jna-platform</artifactId>
<version>5.10.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>2.0.0-alpha1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.github.waffle/waffle-jna -->
<dependency>
<groupId>com.github.waffle</groupId>
<artifactId>waffle-jna</artifactId>
<version>3.0.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.github.waffle/waffle-tomcat9 -->
<dependency>
<groupId>com.github.waffle</groupId>
<artifactId>waffle-tomcat9</artifactId>
<version>3.0.0</version>
<scope>runtime</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>3.3.2</version>
</plugin>
</plugins>
<finalName>${project.artifactId}</finalName>
</build>
</project>

错误堆栈信息如下 #

Nov 23, 2021 1:29:09 PM org.apache.tomcat.util.digester.Digester startElement
SEVERE: Begin event threw exception
java.lang.ClassNotFoundException: waffle.apache.MixedAuthenticator
at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:433)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:586)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
at org.apache.tomcat.util.digester.ObjectCreateRule.begin(ObjectCreateRule.java:104)
at org.apache.tomcat.util.digester.Digester.startElement(Digester.java:1293)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:518)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:183)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1386)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2725)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:541)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:888)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:824)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1224)
at java.xml/com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:635)
at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1551)
at org.apache.catalina.startup.Catalina.parseServerXml(Catalina.java:617)
at org.apache.catalina.startup.Catalina.load(Catalina.java:709)
at org.apache.catalina.startup.Catalina.load(Catalina.java:746)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:302)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:472)
Nov 23, 2021 1:29:09 PM org.apache.catalina.startup.Catalina parseServerXml
WARNING: Unable to load server configuration from [C:\Users\tangudan\OtherProjects\AMS\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\conf\server.xml]
org.xml.sax.SAXParseException; systemId: file:/C:/Users/tangudan/OtherProjects/AMS/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/conf/server.xml; lineNumber: 157; columnNumber: 149; Error at line [157] column [149]: [waffle.apache.MixedAuthenticator]
at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:1982)
at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:2014)
at org.apache.tomcat.util.digester.Digester.startElement(Digester.java:1296)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:518)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:183)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1386)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2725)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:541)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:888)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:824)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1224)
at java.xml/com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:635)
at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1551)
at org.apache.catalina.startup.Catalina.parseServerXml(Catalina.java:617)
at org.apache.catalina.startup.Catalina.load(Catalina.java:709)
at org.apache.catalina.startup.Catalina.load(Catalina.java:746)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:302)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:472)
Caused by: java.lang.ClassNotFoundException: waffle.apache.MixedAuthenticator
at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:433)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:586)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
at org.apache.tomcat.util.digester.ObjectCreateRule.begin(ObjectCreateRule.java:104)
at org.apache.tomcat.util.digester.Digester.startElement(Digester.java:1293)
... 21 more
Nov 23, 2021 1:29:09 PM org.apache.catalina.startup.Catalina start
SEVERE: Cannot start server, server instance is not configure

解决建议 #

• 统一所有waffle相关依赖的版本：当前pom中waffle各组件版本混乱（waffle-jetty为1.9.1、waffle-shiro为3.0.0、waffle-spring-security4为1.8.2），版本不一致会导致类缺失、逻辑冲突，将所有waffle相关依赖统一为3.0.0版本即可。
• 调整waffle依赖的加载方式：Tomcat加载server.xml配置时使用自身的类加载器，不会读取项目WAR包内WEB-INF/lib下的依赖，因此需要将waffle-tomcat9、waffle-jna、jna、jna-platform这几个包放到Tomcat安装目录的lib文件夹下，同时在pom中将这几个依赖的scope改为provided，避免打包到WAR包内引发重复加载冲突。
• 修正server.xml中的类全限定名：waffle 3.x版本适配Tomcat9的MixedAuthenticator类路径已调整为waffle.apache.tomcat9.MixedAuthenticator，旧版本的waffle.apache.MixedAuthenticator在3.x版本中已不存在，将server.xml中对应配置的类路径修改为正确路径即可。
• 修正JDBC驱动版本匹配问题：当前项目编译运行的JDK版本为1.8，但依赖的mssql-jdbc为适配JRE16的9.4.0.jre16版本，建议替换为适配JRE8的9.4.0.jre8版本，避免JDBC相关兼容性问题。

内容的提问来源于stack exchange，提问作者Anudeep Tangudu