java - 没有 [javax.persistence.EntityManager] 类型的限定 bean

Question

我正在尝试构建一个全新的 Spring Framework 4.0 项目，没有所有神奇的 gradle 东西，只是简单地把它踢过老派。

我正在学习这里的教程:http://spring.io/guides/tutorials/data/并且取得了一些成功。我只是卡在这一点上。

/**
 * 
 */
package com.corrisoft.air.db.integration;

import javax.persistence.EntityManager;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.transaction.TransactionConfiguration;
import org.springframework.transaction.annotation.Transactional;

import com.corrisoft.air.db.JPAConfiguration;

import static com.corrisoft.air.db.fixture.JPAAssertions.assertTableExists;
import static com.corrisoft.air.db.fixture.JPAAssertions.assertTableHasColumn;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = { JPAConfiguration.class })
@Transactional
@TransactionConfiguration(defaultRollback = true)
public class PersonMappingIntegrationTests {

    @Autowired
    EntityManager manager;

    @Test
    public void thatItemCustomMappingWorks() throws Exception {
        assertTableExists(manager, "PERSONS");

        assertTableHasColumn(manager, "PERSONS", "FIRST_NAME");
        assertTableHasColumn(manager, "PERSONS", "LAST_NAME");
    }
}

当我运行这个单元测试时，我得到以下堆栈跟踪:

SEVERE: Caught exception while allowing TestExecutionListener [org.springframework.test.context.support.DependencyInjectionTestExecutionListener@68c884e] to prepare test instance [com.corrisoft.air.db.integration.PersonMappingIntegrationTests@7448bc3d]
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.corrisoft.air.db.integration.PersonMappingIntegrationTests': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: javax.persistence.EntityManager com.corrisoft.air.db.integration.PersonMappingIntegrationTests.manager; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [javax.persistence.EntityManager] is defined: expected single matching bean but found 2: entityManager,org.springframework.orm.jpa.SharedEntityManagerCreator#0
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:292)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:384)
    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:326)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:212)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:232)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:175)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: javax.persistence.EntityManager com.corrisoft.air.db.integration.PersonMappingIntegrationTests.manager; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [javax.persistence.EntityManager] is defined: expected single matching bean but found 2: entityManager,org.springframework.orm.jpa.SharedEntityManagerCreator#0
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:508)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    ... 26 more
Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [javax.persistence.EntityManager] is defined: expected single matching bean but found 2: entityManager,org.springframework.orm.jpa.SharedEntityManagerCreator#0
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:967)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:855)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
    ... 28 more

根据观察和研究，它似乎告诉我有两个 EntityManager 类。第一个来自hibernate JPA jar，但找不到第二个。它似乎告诉我它在 Spring ORM 中，但该类中没有定义。

这是测试中使用的 JPAConfiguration 类:

/**
 * 
 */
package com.corrisoft.air.db;

import java.sql.SQLException;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
import org.springframework.orm.hibernate4.HibernateExceptionTranslator;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import com.corrisoft.air.db.repository.PersonsRepository;

/**
 * @author Corrisoft Android Development
 * 
 */
@Configuration
@EnableJpaRepositories(basePackages = "com.corrisoft.db.repository", includeFilters = @ComponentScan.Filter(value = { PersonsRepository.class }, type = FilterType.ASSIGNABLE_TYPE))
@EnableTransactionManagement
public class JPAConfiguration {

    @Bean
    public DataSource dataSource() throws SQLException {
        EmbeddedDatabaseBuilder builder = new EmbeddedDatabaseBuilder();
        return builder.setType(EmbeddedDatabaseType.H2).build();
    }

    @Bean
    public EntityManagerFactory entityManagerFactory() throws SQLException {

        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        vendorAdapter.setGenerateDdl(true);

        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
        factory.setJpaVendorAdapter(vendorAdapter);
        factory.setPackagesToScan("com.corrisoft.air.model");
        factory.setDataSource(dataSource());
        factory.afterPropertiesSet();

        return factory.getObject();
    }

    @Bean
    public EntityManager entityManager(EntityManagerFactory entityManagerFactory) {
        return entityManagerFactory.createEntityManager();
    }

    @Bean
    public PlatformTransactionManager transactionManager() throws SQLException {
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(entityManagerFactory());
        return txManager;
    }

    @Bean
    public HibernateExceptionTranslator hibernateExceptionTranslator() {
        return new HibernateExceptionTranslator();
    }
}

Answer 1

EntityManager接口(interface)属于JPA，由JPA提供者(如Eclipse)实现，不是Spring，它有自己的注入(inject)注解:@PersistenceContext。 EntityManager 对象是事务范围的，不应像您正在做的那样公开为 bean。相反，要么使用 JPA 注释来注入(inject) EntityManager:

@PersistenceContext
EntityManager em;

或者，由于您似乎正在尝试使用 Spring 存储库，请改为注入(inject)存储库:

@Autowired
PersonRepository pr;