Idea when you run a Web project, Tip java.lang.ClassNotFoundException:com.mysql.jdbc.Driver Workaround

Today, I wrote a project with idea. The result is the final error message, as follows:

Java.lang.ClassNotFoundException:com.mysql.jdbc.Driver
At Org.apache.catalina.loader.WebappClassLoader.loadClass (webappclassloader.java:1647)
At Org.apache.catalina.loader.WebappClassLoader.loadClass (webappclassloader.java:1493)
At JAVA.LANG.CLASS.FORNAME0 (Native Method)
At Java.lang.Class.forName (class.java:186)
At Com.google.model.ConnDB.getConn (conndb.java:16)
At Com.google.model.GoodsBeanBO.getGoodsBean (goodsbeanbo.java:23)
At Com.google.servlet.showGoodsClServlet.doGet (showgoodsclservlet.java:41)
At Javax.servlet.http.HttpServlet.service (httpservlet.java:617)
At Javax.servlet.http.HttpServlet.service (httpservlet.java:717)
At Org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (applicationfilterchain.java:290)
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:859)
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:722)
Java.lang.NullPointerException
At Com.google.model.GoodsBeanBO.getGoodsBean (goodsbeanbo.java:25)
At Com.google.servlet.showGoodsClServlet.doGet (showgoodsclservlet.java:41)
At Javax.servlet.http.HttpServlet.service (httpservlet.java:617)
At Javax.servlet.http.HttpServlet.service (httpservlet.java:717)
At Org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (applicationfilterchain.java:290)
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:859)
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:722)

I looked through it several times and found no mistakes. Depressed to die. Debugging... Debugging... Debugging... Ah, man!

A few hours of wasted time! Unexpectedly brain remnants of forget Google! Finally Google a bit. The results came up.

It turned out that Tomcat could not find the MySQL jar package!

Mysql-connector-java-5.1.7-bin.jar must be imported into Tomcat's lib directory! fuck!

In a Java project, you just need to introduce Mysql-connector-java-5.1.7-bin.jar to run a Java project.

In a Web project, when Class.forName ("Om.mysql.jdbc.Driver"), MyEclipse is not going to find the string and will not look for the driver. So just copy the Mysql-connector-java-5.1.7-bin.jar to the Tomcat under the Lib directory.

Record here especially! Record your own stupidity! At the same time thank http://blog.csdn.net/huangbiao86/article/details/6428608 this friend's post!!

Idea when you run a Web project, Tip java.lang.ClassNotFoundException:com.mysql.jdbc.Driver Workaround