排查BUg的思路？
最重要的一点是，错误出现在jsp，
Jsp的错误行数和实际代码对不上，因为jsp编译之后的.class和.jsp的代码行数不一样，所以定位不到jsp的哪一行代码报错。
那么怎么解决？只能靠猜。
因为报错-控制针异常，所以大概知道是后台的几个数据肯定有一个数据是空，但是打印数据集合，每个集合都是有数据的。
那么，进一步判断，是集合里的数据，有为空的。
那么具体是哪个集合？.jsp即使报错，但是正确的数据已经显示，错误的数据空白不显示。据此，进一步知道是哪个集合数据报错。
那么，具体是集合里的哪个数据报错呢？这个不重要，因为看了一下代码，是因为字符串.去掉空格()，这里报错。
所以，最终的解决方法是，把trim()方法去掉即可。
果然，去掉之后，查询数据正常，而且有个集合里的数据是null。null就显示null。
当然，这个是临时的解决方法。
后面的具体解决方案，不讨论。
其他解决方法
.jsp里，也可以打印日志。可以根据.jsp里的日志，排查问题。
基于日志，解决线上BUg，永远是最好的办法。因为这样是有思路的，而不是靠猜。没有思路，就是浪费时间。
日志
日志
2019-10-17 20:33:00,327 INFO [com.gzh.web.action.search.SearchProject.createReady:124] - select userAccount,userName from roleuserview where status='在职' and roleName='销售' or roleName='销售总监' and companyId='31' group by userAccount,userName order by userName asc
2019-10-17 20:33:00,328 INFO [com.gzh.web.action.search.SearchProject.createReady:161] - select userAccount,userName from roleuserview where roleName='优化师' or roleName='优化主管' or roleName='优化总监' and companyId='31' group by userAccount,userName order by userName as
2019-10-17 20:33:00,412 INFO [com.gzh.web.action.search.SearchProject.doPost:77] - Exception
org.apache.jasper.JasperException: java.lang.NullPointerException //空指针异常
at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:556)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:747)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:485)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:410)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:337) //java-跳转
at com.gzh.web.action.search.SearchProject.createReady(SearchProject.java:198) //java
at com.gzh.web.action.search.SearchProject.doPost(SearchProject.java:54)
at com.gzh.web.action.search.SearchProject.doGet(SearchProject.java:39)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.gzh.web.util.SessionFilter.doFilter(SessionFilter.java:66)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at org.apache.jsp.search.searchProject_jsp._jspService(searchProject_jsp.java:361) //jsp代码报错
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:439)
... 40 more
说明
错误栈，
1..java
2.跳转
在Java里跳转到jsp
3..jsp报错
最神奇的是，从Java到jsp的调用栈，完全记录了。
这个，就和.java调用另一个.java的方法一样，因为.jsp最终也是被编译为.class才运行的。
