我是新手。当我启动时，日志显示以下错误。我无法导入MySQL数据。 Solr版本是5.5.4
org.apache.solr.common.SolrException: Bad contentType for search handler :null request={qt=/dataimport&commit=true&clean=true&command=full-import}
at org.apache.solr.request.json.RequestUtil.processParams(RequestUtil.java:72)
at org.apache.solr.util.SolrPluginUtils.setDefaults(SolrPluginUtils.java:172)
at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:152)
at org.apache.solr.core.SolrCore.execute(SolrCore.java:2102)
at org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:654)
at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:460)
at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:257)
at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:208)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
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:493)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)
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:744)
看，是什么原因引起的？
谢谢