Question

我正在使用：

cassandra for windows（datastax community 2.1.7）;
intellij 14.1.2 ultimate;
spring 4.1.5;
卡桑德拉-全1.1.0
卡桑德拉-JDBC-1.1.1;
卡桑德拉-节俭1.1.0;

现在我尝试制作最简单的cql select语句并获取结果集：

String query = "SELECT title,prod_year FROM mediaitems;";
Statement st = this.conn.createStatement();
ResultSet rs = st.executeQuery(query);

也使用PreparedStatement而不仅仅是Statement：

String query = "SELECT title,prod_year FROM mediaitems;";
PreparedStatement ps = this.conn.prepareStatement(query);
ResultSet rs = ps.executeQuery();

这是我的cassandra表：

CREATE TABLE items.mediaitems (
  mid uuid PRIMARY KEY,
  prod_year int,
  title text,
  title_length int
)

问题是我一直从ResultSet行直接抛出NullPointerException。

我在TypedColumn.class第23行跟踪问题：

this.nameString = comparator.getString(column.name);

这里的comperator由于某种原因是null。 comperator在CassandraResultSet.class第804行中设置：

AbstractJdbcType comparator = TypesMap.getTypeForComparator(nameType == null?this.schema.default_name_type:nameType);

我真的不知道如何使这项工作......当我使用INSERT PreparedStatements时，一切正常，数据库响应并保存记录，因此与数据库的连接没有任何问题。

另外，当我在cql-shell中尝试我的select查询时，它也能正常工作。

我尝试将cassandra驱动程序升级到：

卡桑德拉-全2.1.6
卡桑德拉-JDBC-1.2.5
卡桑德拉-节俭2.1.6

但是与数据库的连接甚至无法在这里工作。

请帮忙！我错过了什么？

编辑1：

这是＆＃34; SELECT标题，prod_year FROM items.mediaitems;＆＃34;的堆栈错误按照评论中的要求：

22:18:05.674 [http-apr-9090-exec-8] DEBUG o.a.c.cql.jdbc.CassandraDriver - Final Properties to Connection: {portNumber=9160, databaseName=items, serverName=localhost}
22:18:05.681 [http-apr-9090-exec-8] INFO  o.a.c.cql.jdbc.CassandraConnection - Connected to localhost:9160 using Keyspace items and CQL version 2.0.0
java.lang.NullPointerException
at org.apache.cassandra.cql.jdbc.TypedColumn.<init>(TypedColumn.java:45)
at org.apache.cassandra.cql.jdbc.CassandraResultSet.createColumn(CassandraResultSet.java:972)
at org.apache.cassandra.cql.jdbc.CassandraResultSet.populateColumns(CassandraResultSet.java:156)
at org.apache.cassandra.cql.jdbc.CassandraResultSet.<init>(CassandraResultSet.java:130)
at org.apache.cassandra.cql.jdbc.CassandraStatement.doExecute(CassandraStatement.java:167)
at org.apache.cassandra.cql.jdbc.CassandraStatement.executeQuery(CassandraStatement.java:227)
at org.bgu.ise.ddb.items.ItemsController.getTopNItems(ItemsController.java:199)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
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.invokeHandleMethod(RequestMappingHandlerAdapter.java:777)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:706)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
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:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2463)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2452)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)

cassandra结果集不起作用

0 个答案: