好久没来,问个问题,帮忙看一下代码:)
package com.syj.data;
import java.sql.*;
public class DataBase {
Connection conn=null;
Statement st=null;
ResultSet rs=null;
public ResultSet getRs(String query){
try{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
String url="jdbc:microsoft:sqlserver://172.16.244.206:1433;DatabaseName=syj";
String user="sa";
String password="";
Connection conn= DriverManager.getConnection(url,user,password);
Statement stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
rs=st.executeQuery(query);
}catch(Exception e){
e.printStackTrace();
}
return rs;
}
}
错误提示:
java.lang.NullPointerException
at com.syjzw.data.DataBase.getRs(DataBase.java:24)
at org.apache.jsp.index_jsp._jspService(index_jsp.java:96)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:137)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper
.java:210)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:2
95)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV
alve.java:256)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextV
alve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:
2415)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j
ava:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatche
rValve.java:171)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j
ava:172)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal
ve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:22
3)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java
:594)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.proce
ssConnection(Http11Protocol.java:392)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java
:565)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadP
ool.java:619)
at java.lang.Thread.run(Thread.java:534)
java.lang.NullPointerException
at org.apache.jsp.index_jsp._jspService(index_jsp.java:98)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:137)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper
.java:210)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:2
95)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV
alve.java:256)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextV
alve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:
2415)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j
ava:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatche
rValve.java:171)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j
ava:172)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal
ve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContex
t.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:22
3)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java
:594)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.proce
ssConnection(Http11Protocol.java:392)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java
:565)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadP
ool.java:619)
at java.lang.Thread.run(Thread.java:534)