我试了上面的连接数据库的程序出现这样的提示:A Servlet Exception Has Occurred java.lang.NullPointerException at org.apache.jsp.dept$jsp._jspService(dept$jsp.java:86) at org.apache.jasper.runtime.HttpJspBase.service(Unknown Source) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(Unknown Source) at org.apache.jasper.servlet.JspServlet.serviceJspFile(Unknown Source) at org.apache.jasper.servlet.JspServlet.service(Unknown Source) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Unknown Source) at org.apache.catalina.core.ApplicationFilterChain.doFilter(Unknown Source) at org.apache.catalina.core.StandardWrapperValve.invoke(Unknown Source) at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source) at org.apache.catalina.core.StandardPipeline.invoke(Unknown Source) at org.apache.catalina.core.ContainerBase.invoke(Unknown Source) at org.apache.catalina.core.StandardContextValve.invoke(Unknown Source) at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source) at org.apache.catalina.core.StandardPipeline.invoke(Unknown Source) at org.apache.catalina.core.ContainerBase.invoke(Unknown Source) at org.apache.catalina.core.StandardContext.invoke(Unknown Source) at org.apache.catalina.core.StandardHostValve.invoke(Unknown Source) at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source) at org.apache.catalina.valves.AccessLogValve.invoke(Unknown Source) at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source) at org.apache.catalina.core.StandardPipeline.invoke(Unknown Source) at org.apache.catalina.core.ContainerBase.invoke(Unknown Source) at org.apache.catalina.core.StandardEngineValve.invoke(Unknown Source) at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source) at org.apache.catalina.core.StandardPipeline.invoke(Unknown Source) at org.apache.catalina.core.ContainerBase.invoke(Unknown Source) at org.apache.catalina.connector.http.HttpProcessor.process(Unknown Source) at org.apache.catalina.connector.http.HttpProcessor.run(Unknown Source) at java.lang.Thread.run(Thread.java:484)
1、classes12.jar放在TOMCAT_HOME/server/lib下
2、classes12.jar放在yourapphome/WEB-INF/lib下
3、classeses放在TOMCAT_HOME/server/classes下
4、classes放在yourapphome/WEB-INF/classes下
5、放在任何地方,在catalina.bat中设置CLASSPATH
--- ZJQ
2。检查网络连接如果不是连本地库的话!
请写出异常!
java.lang.NullPointerException
at org.apache.jsp.dept$jsp._jspService(dept$jsp.java:86)
at org.apache.jasper.runtime.HttpJspBase.service(Unknown Source)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(Unknown Source)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(Unknown Source)
at org.apache.jasper.servlet.JspServlet.service(Unknown Source)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Unknown Source)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(Unknown Source)
at org.apache.catalina.core.StandardWrapperValve.invoke(Unknown Source)
at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source)
at org.apache.catalina.core.StandardPipeline.invoke(Unknown Source)
at org.apache.catalina.core.ContainerBase.invoke(Unknown Source)
at org.apache.catalina.core.StandardContextValve.invoke(Unknown Source)
at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source)
at org.apache.catalina.core.StandardPipeline.invoke(Unknown Source)
at org.apache.catalina.core.ContainerBase.invoke(Unknown Source)
at org.apache.catalina.core.StandardContext.invoke(Unknown Source)
at org.apache.catalina.core.StandardHostValve.invoke(Unknown Source)
at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source)
at org.apache.catalina.valves.AccessLogValve.invoke(Unknown Source)
at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source)
at org.apache.catalina.core.StandardPipeline.invoke(Unknown Source)
at org.apache.catalina.core.ContainerBase.invoke(Unknown Source)
at org.apache.catalina.core.StandardEngineValve.invoke(Unknown Source)
at org.apache.catalina.core.StandardPipeline.invokeNext(Unknown Source)
at org.apache.catalina.core.StandardPipeline.invoke(Unknown Source)
at org.apache.catalina.core.ContainerBase.invoke(Unknown Source)
at org.apache.catalina.connector.http.HttpProcessor.process(Unknown Source)
at org.apache.catalina.connector.http.HttpProcessor.run(Unknown Source)
at java.lang.Thread.run(Thread.java:484)
tool->enterprise setup->database drivers
设置完后要重启动jbilder,再试试