当我们通过ID过滤列表时，如何使用HQL查询一对多关系

Question

I've a Country entity and a Company entity with relation one to many:

@Entity
public class Country {

    @OneToMany(mappedBy="country")
    private List<Company> companies;

Now, I want to return a list of all the companies in a particular country, but when I run the following code I get an error:

String queryString = "from Country as model where model.companies.id= ?";
Query queryObject = getSession().createQuery(queryString);
queryObject.setParameter(0, value);
return queryObject.list();

This is the cause error I get:

16:39:14,456 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/myserver].[appServlet]] (http-localhost-127.0.0.1-8080-4) Servlet.service() for servlet appServlet threw exception: org.hibernate.QueryException: could not resolve property: Company of: uk.co.bob.domain.Country [from uk.co.bob.domain.Country as model where model.Company.id= ?]
    at org.hibernate.persister.entity.AbstractPropertyMapping.propertyException(AbstractPropertyMapping.java:83) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.persister.entity.AbstractPropertyMapping.toType(AbstractPropertyMapping.java:77) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.persister.entity.AbstractEntityPersister.toType(AbstractEntityPersister.java:1968) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.tree.FromElementType.getPropertyType(FromElementType.java:313) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.tree.FromElement.getPropertyType(FromElement.java:490) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.tree.DotNode.getDataType(DotNode.java:616) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.tree.DotNode.prepareLhs(DotNode.java:267) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.tree.DotNode.resolve(DotNode.java:214) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.tree.DotNode.resolveFirstChild(DotNode.java:178) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.HqlSqlWalker.lookupProperty(HqlSqlWalker.java:577) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.addrExpr(HqlSqlBaseWalker.java:4719) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.expr(HqlSqlBaseWalker.java:1260) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.exprOrSubquery(HqlSqlBaseWalker.java:4426) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.comparisonExpr(HqlSqlBaseWalker.java:3898) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.logicalExpr(HqlSqlBaseWalker.java:2076) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.whereClause(HqlSqlBaseWalker.java:794) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:595) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:299) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:247) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:249) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:184) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:137) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:105) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:80) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:168) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:221) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:199) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1778) [hibernate-core-4.2.4.Final.jar:4.2.4.Final]
    at uk.co.bob.dao.CountryDaoImpl.findByProperty(CountryDaoImpl.java:118) [classes:]
    at uk.co.bob.service.CountryServiceImpl.findByProperty(CountryServiceImpl.java:121) [classes:]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_25]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_25]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_25]
    at java.lang.reflect.Method.invoke(Unknown Source) [rt.jar:1.7.0_25]
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317) [spring-aop-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) [spring-aop-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) [spring-aop-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96) [spring-tx-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260) [spring-tx-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94) [spring-tx-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) [spring-aop-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91) [spring-aop-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) [spring-aop-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204) [spring-aop-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at com.sun.proxy.$Proxy43.findByProperty(Unknown Source)
    at uk.co.bob.controller.HospitalController.showNewHopitalForm(HospitalController.java:96) [classes:]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_25]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_25]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_25]
    at java.lang.reflect.Method.invoke(Unknown Source) [rt.jar:1.7.0_25]
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:219) [spring-web-3.2.3.RELEASE.jar:3.2.3.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132) [spring-web-3.2.3.RELEASE.jar:3.2.3.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) [spring-webmvc-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745) [spring-webmvc-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686) [spring-webmvc-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80) [spring-webmvc-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925) [spring-webmvc-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856) [spring-webmvc-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936) [spring-webmvc-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827) [spring-webmvc-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:734) [jboss-servlet-api_3.0_spec-1.0.0.Final.jar:1.0.0.Final]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812) [spring-webmvc-3.2.4.RELEASE.jar:3.2.4.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) [jboss-servlet-api_3.0_spec-1.0.0.Final.jar:1.0.0.Final]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:]
    at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.13.Final.jar:]
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:]
    at java.lang.Thread.run(Unknown Source) [rt.jar:1.7.0_25]

How should I rewrite my HQL sentence?

Answer 1

I believe you need to JOIN on the companies field

String queryString = "FROM Country AS model JOIN model.companies AS company WHERE company.id= ?";

Depending on what you want to return, you can use a SELECT

String queryString = "SELECT model FROM Country AS model JOIN model.companies AS company WHERE company.id= ?";

Answer 2

如果要访问关系的属性，则必须使用JOIN ，为关联和别名提供通过此别名的访问属性：

from Country as model join model.companies c where c.id = ?

Answer 3

请确保private List<Company> companies;公共设置者和获取者private List<Company> companies;