solr的高亮空指针异常分析

在做solr的高亮展示时老是提示这个异常:

严重: Servlet.service() for servlet [springmvc] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
	at cn.bbb.dao.JdDaoImpl.selectProductModelListByQuery(JdDaoImpl.java:97)
	at cn.bbb.service.JdServiceImpl.selectProductModelListByQuery(JdServiceImpl.java:21)
	at cn.bbb.controller.JdController.selectProductModelListByQuery(JdController.java:28)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969)
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:871)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)

随后发现在搜索product_name域里存在的内容就不会报错,但是搜索没有的内容就会报这个错.

于是我加上了非空判断

    

即使搜索此域没有的内容也不再报错了,鬼鬼,结束了?没有.

我随后又发现搜索结果商品名称出现这个问题:

    

随后想起solr core1配置:

    

网上看了一些资料,才发现原因所在.

由于product_keywords存在两个域的值,所以即使我搜索product_name里没有的内容,也会有内容展示,因为product_description里存在,所以两者之一只要有一个域存在相关filed就ok.

solr的高亮是拿product_name域的value与用户的term("XXX")对比进行高亮展示,当我们搜索只在product_description域里单独存在的内容时,此时返回的product_name的value不会与用户的term("XXX")匹配成功,所以最终返回的内容为null;

清楚了其中的关系之后,我对代码做出如下修改:

    

结果如下:

    

可以看到,即使商品名称不与关键词匹配,也不会出现不显示商品名称的情况,而匹配的话也能正常显示高亮.

综上,问题解决.

总结:干这行知道其运行流程原理什么的太重要了,知道了这些解决问题的速度会快上很多.