Question

我尝试将Spring Data jpa与泛型一起使用但在运行单元测试时会处理相同的异常。这是例外：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'tn.moussi.PostRepositorytest': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: tn.moussi.repositories.PostRepository tn.moussi.PostRepositorytest.repository; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'postRepository': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: T is not mapped [select t from T t where t.title = :TITLE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:287)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:374)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:110)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:313)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:211)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:288)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:284)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:88)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: tn.moussi.repositories.PostRepository tn.moussi.PostRepositorytest.repository; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'postRepository': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: T is not mapped [select t from T t where t.title = :TITLE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:506)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)
    ... 26 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'postRepository': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: T is not mapped [select t from T t where t.title = :TITLE]
    at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:149)
    at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:102)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1442)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:248)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:876)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:818)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:735)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478)
    ... 28 more
Caused by: java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: T is not mapped [select t from T t where t.title = :TITLE]
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1364)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1300)
    at org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:294)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:365)
    at com.sun.proxy.$Proxy22.createQuery(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
    at com.sun.proxy.$Proxy20.createQuery(Unknown Source)
    at org.springframework.data.jpa.repository.query.SimpleJpaQuery.<init>(SimpleJpaQuery.java:69)
    at org.springframework.data.jpa.repository.query.SimpleJpaQuery.fromQueryAnnotation(SimpleJpaQuery.java:132)
    at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$DeclaredQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:114)
    at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$CreateIfNotFoundQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:160)
    at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$AbstractQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:68)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.<init>(RepositoryFactorySupport.java:280)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:148)
    at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.getObject(RepositoryFactoryBeanSupport.java:125)
    at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.getObject(RepositoryFactoryBeanSupport.java:41)
    at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:142)
    ... 36 more
Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: T is not mapped [select t from T t where t.title = :TITLE]
    at org.hibernate.hql.internal.ast.util.SessionFactoryHelper.requireClassPersister(SessionFactoryHelper.java:180)
    at org.hibernate.hql.internal.ast.tree.FromElementFactory.addFromElement(FromElementFactory.java:110)
    at org.hibernate.hql.internal.ast.tree.FromClause.addFromElement(FromClause.java:93)
    at org.hibernate.hql.internal.ast.HqlSqlWalker.createFromElement(HqlSqlWalker.java:324)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3291)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:3180)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:706)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:562)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:299)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:247)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:248)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:183)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:105)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:80)
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:168)
    at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:221)
    at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:199)
    at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1735)
    at org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:291)
    ... 58 more

这是java代码：

import java.io.Serializable;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;


public interface GenericRepository<T,ID extends Serializable> extends JpaRepository<T, ID> {

    @Query("select t from T t where t.title = :TITLE")
    T findByTitle(@Param("TITLE") String title);

}

import org.springframework.stereotype.Repository;

import tn.moussi.entities.Post;

@Repository("postRepository")
public interface PostRepository extends GenericRepository< Post, Integer> {


}

单元测试：

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:META-INF/application-context.xml")
public class PostRepositorytest {


    @Autowired
    @Qualifier(value="postRepository")
    PostRepository repository;

    @Test
    public void test() {
        Post post = new Post();
        post.setPostDate(new Date());
        post.setTitle("first post");

        repository.save(post);

        Post dbpost = repository.findByTitle(post.getTitle());
        assertNotNull(dbpost);
        System.out.println(dbpost.getTitle());

    }

}

实体类帖子：

@Entity
@Table(name="POST")
public class Post{

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="POST_ID")
    Integer postId;

    @Column(name="TITLE")
    String title;
    @Column(name="POST_DATE")
    Date postDate;

    public Integer getPostId() {
        return postId;
    }
    public void setPostId(Integer postId) {
        this.postId = postId;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public Date getPostDate() {
        return postDate;
    }
    public void setPostDate(Date postDate) {
        this.postDate = postDate;
    }
}

应用程序上下文文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.1.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.2.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd">

<!-- database -->
<jdbc:embedded-database id="datasource" type="H2"></jdbc:embedded-database>

<!--  Entity manager -->
 <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
  <property name="dataSource" ref="datasource"/>
        <property name="persistenceUnitName" value="moussi-tutorial"/>
 </bean>

 <!--  Transaction Manager -->
 <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory"/>
  </bean>

 <!--  Jap repositories -->
 <jpa:repositories base-package="tn.moussi"></jpa:repositories>

<context:annotation-config/>
    <context:component-scan base-package="tn.moussi" />

</beans>

persistence.xml文件：

<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="1.0">

  <persistence-unit name="moussi-tutorial" transaction-type="RESOURCE_LOCAL">
     <provider>org.hibernate.ejb.HibernatePersistence</provider>

    <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
         <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
         <property name="hibernate.show_sql" value="true"/>
      </properties>
  </persistence-unit>

</persistence>

Answer 1

这不会像你期望的那样起作用。虽然具体类继承了该方法并允许我们在运行时查找具体的返回类型，但我们不能（不能）对手动定义的查询进行任何泛型替换。之所以没有办法确定你是否真的从查询中引用泛型类型（读取：你的查询中的T本质上意味着什么，只是查看查询）。

您拥有的选项是为每种具体类型的T引入专用命名查询，例如TypeA.findByTitle，TypeB.findByTitle等。然后我们使用这些来支持继承到具体存储库接口的方法。此外，您可能希望使用@NoRepositoryBean注释GenericRepository接口，以防止在组件扫描期间拾取它。请阅读reference documentation中的相关详细信息。

Answer 2

我不确定这是可能的。问题是通用参数T对于每个接口都是不同的。在@Query T中，在注释的值元素select t from T...中静态定义。在普通的JPA查询中，将在查询中指定实体的类型。如下：

@Query("select t from Book t where t.title = :TITLE")
Book findByTitle(@Param("TITLE") String title);

如果允许扩展接口，Spring Data需要足够智能以在运行时确定泛型参数T的类型（由于大多数操作都是编译时间，因此与泛型有关。然后，它需要将此类型替换为@Query注释的value元素中的静态定义查询。我没有看到任何证据证明这是可能的。

Answer 3

我猜可能是因为您的JPA提供程序无法在GenericRepository接口中处理查询：

select t from T t where t.title = :TITLE

为了理解这是否是根本原因 - 尝试在PostRepository中引入另一个findByTitle2方法来解决显式命名的实体：

@Query("select t from Post t where t.title = :TITLE")
T findByTitle(@Param("TITLE") String title);

请注意，您的堆栈跟踪使用以下报告解决此问题：

QuerySyntaxException: T is not mapped [select t from T t where t.title = :TITLE]

我不确定这样的查询参数化select t from T t where t.title = :TITLE是否可行 - 由于java中泛型实现的细节，并不总是可以在运行时提取正确的参数化类型信息来决定使用什么类型在你的申请的某一点。

单元测试时无法自动装配字段

3 个答案: