eclipse_J2EE连接数据库报错(JAVAWEB项目出错)

#eclipse_J2EE连接数据库报错(JAVAWEB项目出错)

##java.lang.ClassNotFoundException: com.mysql.jdbc.Driver 解决方法

####下面是类似的错误信息
>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)

##解决办法

###1、先把mysql-connector-java-5.1.7-bin.jar导入到tomcat的lib目录下面！ 

###2、在java项目中，只需要引入mysql-connector-java-5.1.7-bin.jar就可以运行java项目。

###3、在web项目中，当Class.forName("om.mysql.jdbc.Driver");时myeclipse是不会去查找字符串，不会去查找驱动的。所以只需要把mysql-connector-java-5.1.7-bin.jar拷贝到tomcat下lib目录就可以了。

###4、如下图

###5、再次运行项目就好