这个是什么错误

Question

八月 31, 2017 4:27:30 下午 org.apache.catalina.core.StandardWrapperValve invoke

严重: Servlet.service() for servlet [SublistServlet] in context with path [/pager] threw exception

java.lang.RuntimeException: get connection error!

at com.imooc.page.util.JdbcUtil.getConnection(JdbcUtil.java:66)

at com.imooc.page.dao.SublistStudentDaoImpl.getAllStudent(SublistStudentDaoImpl.java:56)

at com.imooc.page.dao.SublistStudentDaoImpl.findStudent(SublistStudentDaoImpl.java:18)

at com.imooc.page.service.SublistStudentServiceImpl.findStudent(SublistStudentServiceImpl.java:20)

at com.imooc.page.servlet.SublistServlet.doPost(SublistServlet.java:70)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)

at com.imooc.page.EncodingFilter.doFilter(EncodingFilter.java:26)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)

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

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)

at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)

at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783)

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

at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434)

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

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

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

at java.lang.Thread.run(Thread.java:745)

Caused by: java.lang.NullPointerException

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

at java.lang.Class.forName(Class.java:264)

at com.imooc.page.util.JdbcUtil.getConnection(JdbcUtil.java:63)

... 31 more

Answer 1

数据库连不上,检查一下你的数据库服务开启没有,