mongodb eclipse java.lang.ClassNotFoundException: com.mongodb.MongoClient

Posted 2023-03-22

【中文标题】mongodb eclipse java.lang.ClassNotFoundException: com.mongodb.MongoClient

【英文标题】：

【发布时间】：2022-01-23 21:22:28

【问题描述】：

我正在尝试在 Eclipse 上使用 mongoDB，但出现错误： java.lang.ClassNotFoundException: com.mongodb.MongoClient.

我已将 jar 文件添加到类路径库中：

但仍然出现错误：

严重：

Servlet.service() for servlet [spring-mvc] in context with path [/project] threw exception [Handler processing failed; nested exception is java.lang.NoClassDefFoundError: com/mongodb/MongoClient] with root cause
java.lang.ClassNotFoundException: com.mongodb.MongoClient
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1332)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1166)
    at org.bgu.ise.ddb.registration.RegistarationController.validateUser(RegistarationController.java:100)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:568)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:777)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:706)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:833)

我有所有的进口：

import com.mongodb.*;
import com.mongodb.client.MongoClients;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;
import com.mongodb.MongoCredential;

和代码：

      client = new MongoClient( "localhost" , 27017 );
      client.close();

【问题讨论】：

将...-javadoc.jar文件添加到类路径没有任何效果，因为它们不包含Java字节码，而只包含Javadoc html文件（相反，那些...-javadoc.jar文件旨在配置在Javadoc 位置 带有字节码的相应真实 JAR 的子节点）。

【参考方案1】：

将 jars 添加到 Classpath 足以针对其内容进行编译，但这并不能告诉服务器工具您希望在启动服务器时部署它们。检查项目的部署程序集属性页。

【讨论】：

另外，前三个 JAR 是 ...-javadoc.jar 文件，我猜这些应该是带有字节码的真实 JAR，对吧？