<%这个是JSP文件里调用的findById方法，
}else if("edit".equals(action)){
Integer id = Integer.parseInt(request.getParameter("id"));
CalendarDao calendarDao = new CalendarDaoImpl();
Calendar calendar = new CalendarDaoImpl().findById(id);
Calendar calendar = calendarService.findById(id);这个是java文件中调用的findById方法；
String start = calendar.getStart();
@Override
public Calendar findById(Integer id) {
// TODO Auto-generated method stub
System.out.println(id);
String sql = "select * from fullcalendar where id = "+id;
List<Map<String, Object>> list = null;
try{
list = jdbcTemplate.queryForList(sql);
}catch(Exception e){
e.printStackTrace();
}
Map<String, Object> map = list.get(0);
Calendar calendar = new Calendar();
calendar.setId(Integer.parseInt(map.get("id").toString()));
calendar.setTitle(map.get("title").toString());
calendar.setStart(map.get("start").toString());
calendar.setEnd(map.get("end").toString());
calendar.setAllDay(Integer.parseInt(map.get("allday").toString()));
calendar.setColor(map.get("color").toString());
return calendar;
}
这个是dao层里面的方法。
我从java文件里面调用这个方法都能打印出来，为什么从JSP文件里调用就提示空指针，错误如下：
SEVERE: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at com.njceb.dao.impl.CalendarDaoImpl.findById(CalendarDaoImpl.java:97)
at org.apache.jsp.pages.event_jsp._jspService(event_jsp.java:190)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
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.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:108)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.njceb.interceptor.JspReqFilter.doFilter(JspReqFilter.java:108)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:128)
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:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)
这个只是我写的一个日程控件的Demo，初学者，只想知道什么原因，请大侠们能够给错误说下原理，接触JAVA不久，还请多多指教。
