java.lang.NoClassDefFoundError：netBeans 中的 javax/servlet/http/HttpServlet netbeans

Question

我正在开发一个 servlet，当我提交 servlet 时，它会从 index.jsp 表单中获取一些详细信息，并抛出以下异常。我正在使用 NetBeans 和 Apache Tomcat/10.0.16。

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HTTP Status 500 \xe2\x80\x93 Internal Server Error \nType Exception Report\n\nMessage Error instantiating servlet class [com.authFilter.AdminServlet]\n\nDescription The server encountered an unexpected condition that prevented it from fulfilling the request.\n\nException\n\njakarta.servlet.ServletException: Error instantiating servlet class [com.authFilter.AdminServlet]\n    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)\n    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\n    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)\n    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:355)\n    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)\n    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)\n    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:866)\n    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1708)\n    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\n    org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)\n    org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)\n    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\n    java.base/java.lang.Thread.run(Thread.java:832)\nRoot Cause\n\njava.lang.NoClassDefFoundError: javax/servlet/http/HttpServlet\n    java.base/java.lang.ClassLoader.defineClass1(Native Method)\n    java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)\n    java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:151)\n    org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2516)\n    org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:872)\n    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1408)\n    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1252)\n    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)\n    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\n    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)\n    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:355)\n    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)\n    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)\n    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:866)\n    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1708)\n    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\n    org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)\n    org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)\n    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\n    java.base/java.lang.Thread.run(Thread.java:832)\nRoot Cause\n\njava.lang.ClassNotFoundException: javax.servlet.http.HttpServlet\n    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1444)\n    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1252)\n    java.base/java.lang.ClassLoader.defineClass1(Native Method)\n    java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)\n    java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:151)\n    org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2516)\n    org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:872)\n    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1408)\n    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1252)\n    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)\n    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\n    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)\n    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:355)\n    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)\n    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)\n    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:866)\n    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1708)\n    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\n    org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)\n    org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)\n    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\n    java.base/java.lang.Thread.run(Thread.java:832)\n

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我该如何解决这个问题，我能做什么？

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我添加这个依赖项

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<dependency>\n    <groupId>javax.servlet</groupId>\n    <artifactId>javax.servlet-api</artifactId>\n    <version>3.1.0</version>\n    <scope>provided</scope>\n</dependency>\n\n

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在 pom.xml 上，但它不起作用。

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我在网上搜索了它的解决方案但没有找到。

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所以帮我找出这个错误的解决方案。

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Answer 1

我遇到了同样的问题，然后我发现 Tomcat10 支持 jakarta.servlet，因此将您的依赖项替换为以下依赖项：

<dependency>
   <groupId>jakarta.servlet</groupId>
   <artifactId>jakarta.servlet-api</artifactId>
   <version>5.0.0</version>
   <scope>provided</scope>
</dependency>

根据 Tomcat 网站的说法：“Tomcat 9.0.x 和 Tomcat 10.0.x 之间存在重大重大变化。规范 API 使用的 Java 包已从 javax...更改为 jakarta...需要重新编译针对新 API 的 Web 应用程序。”