无法在 QueryDslJdbcTemplate 上调用 list() 方法答案

【问题标题】：Can't invoke list() method on QueryDslJdbcTemplate无法在 QueryDslJdbcTemplate 上调用 list() 方法
【发布时间】：2025-12-23 13:55:06
【问题描述】：

我正在使用 Spring jdbc 来获取特定列的不同元素：

template.newSqlQuery().from(qCustomer).groupBy(qCustomer.name).list(qCustomer.name);

根据官方documentation of querydsl看来一切正常

但我明白了：

GRAVE: The RuntimeException could not be mapped to a response, re-throwing to the HTTP container
java.lang.NullPointerException
    at com.mysema.query.sql.AbstractSQLQuery.iterateSingle(AbstractSQLQuery.java:434)
    at com.mysema.query.sql.AbstractSQLQuery.iterate(AbstractSQLQuery.java:367)
    at com.mysema.query.sql.AbstractSQLQuery.list(AbstractSQLQuery.java:488)
    at com.dao.springdata.SpringDataLogRecordDAO.selectRecord(SpringDataLogRecordDAO.java:167)
    at com.domain.logic.LogRecordServiceImpl.selectRecord(LogRecordServiceImpl.java:41)
    at com.restservice.IOSLogsReporter.datatables(IOSLogsReporter.java:94)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:167)
    at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:70)
    at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:279)
    at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:86)
    at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:136)
    at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:74)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1347)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1279)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1229)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1219)
    at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:419)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
    at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:886)
    at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:834)
    at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:795)
    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:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:931)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
    at java.lang.Thread.run(Thread.java:680)
19 avr. 2013 20:56:13 org.apache.catalina.core.StandardWrapperValve invoke
GRAVE: "Servlet.service()" pour la servlet default a g?n?r? une exception
java.lang.NullPointerException
    at com.mysema.query.sql.AbstractSQLQuery.iterateSingle(AbstractSQLQuery.java:434)
    at com.mysema.query.sql.AbstractSQLQuery.iterate(AbstractSQLQuery.java:367)
    at com.mysema.query.sql.AbstractSQLQuery.list(AbstractSQLQuery.java:488)
    at com.dao.springdata.SpringDataLogRecordDAO.selectRecord(SpringDataLogRecordDAO.java:167)
    at com.domain.logic.LogRecordServiceImpl.selectRecord(LogRecordServiceImpl.java:41)
    at com.restservice.IOSLogsReporter.datatables(IOSLogsReporter.java:94)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:167)
    at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:70)
    at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:279)
    at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:86)
    at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:136)
    at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:74)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1347)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1279)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1229)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1219)
    at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:419)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
    at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:886)
    at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:834)
    at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:795)
    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:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:931)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
    at java.lang.Thread.run(Thread.java:680)

我错过了什么吗？有没有更好的方法来做到这一点？

【问题讨论】：

你能发布完整的堆栈跟踪吗？
我刚刚更新了帖子
哪个Querydsl版本？

标签： jdbctemplate spring-jdbc querydsl

【解决方案1】：

查询的JDBC连接好像是空的https://github.com/mysema/querydsl/blob/QUERYDSL_2_2_2/querydsl-sql/src/main/java/com/mysema/query/sql/AbstractSQLQuery.java#L434

【讨论】：

如果我删除 list(qCustomer.name) 它工作正常。请注意，我也使用相同的 jdbc 连接来获取其他数据，它运行良好，所以我认为这不是 JDBC 连接问题
如果您使用的是事务绑定连接，请确保该方法是事务性的。

【解决方案2】：

这种替代方法效果很好：

template.query(template.newSqlQuery().from(qCustomer).groupBy(qCustomer.name), qCustomer.name);

【讨论】：

是的，从 newSqlQuery() 返回的 SQLQuery 实例似乎没有附加连接。这似乎确实是它应该与 Spring Data JDBC 一起使用的方式
关于该问题的任何更新？我在使用 list 方法和 Spring querydslJdbcTemplate 时遇到了同样的问题。如果它应该与 Spring JDBC 一起使用，我们如何处理 SubQueries ？在我的情况下，我想动态联合所有子查询列表。但是对于每个子查询，我必须指定投影 .list(Wildcard.all)