Throughout my application I want to add the username and password to database when a user registers and clicks on "sign up" through servlet2.java but on local tomcat deployment instead of adding data to database class not found exception is thrown, I have already added mysql jar to lib but still no benefit. Here is the downloadable link to my project. If anybody can please help correcting the issue.

Here is the full stack trace.

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1363)

at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1186)

at java.base/java.lang.Class.forName0(Native Method)

at java.base/java.lang.Class.forName(Class.java:315)

at source.servlet2.database(servlet2.java:23)

at source.servlet2.doPost(servlet2.java:16)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)

at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)

at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)

at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)

at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1415)

at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)

at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.base/java.lang.Thread.run(Thread.java:834)

22-May-2019 19:22:52.550 INFO [Catalina-utility-2] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [D:\apache-tomcat-9.0.17\webapps\manager]

22-May-2019 19:22:52.735 INFO [Catalina-utility-2] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [D:\apache-tomcat-9.0.17\webapps\manager] has finished in [185] ms

解决方案

You have the provided scope for the jdbc driver jar. In this cases it is not copied into the artifact that you deploy to tomcat. You need to specify it as a compile scope.

You can also add the to tomcat classpath jar as described here https://stackoverflow.com/a/7198049/2000323 for all applications. Then you must specify the scope as provided so that the same jar would not be deployed twice.