Question

我正在配置我的JPA2 + Spring项目并尝试使用JPARepositories但我似乎在自动装配的存储库对象上获得Null Pointer Exception。请查看代码并帮助我确定我缺少的内容。

Pom.xml
    <dependencies>
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.1.1</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-commons-core</artifactId>
        <version>1.4.1.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate.java-persistence</groupId>
        <artifactId>jpa-api</artifactId>
        <version>2.0-cr-1</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.7.5</version>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.14</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-jpa</artifactId>
        <version>1.2.0.RELEASE</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>r09</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.11</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>3.2.4.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>3.2.4.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>3.2.4.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>3.2.4.RELEASE</version>
    </dependency>
</dependencies>

的persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1"
xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence    
    http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="Testing124"
    transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>com.myclassregister.model.base.misc.School</class>
    <shared-cache-mode>ENABLE_SELECTIVE</shared-cache-mode>
    <properties>
        <property name="eclipselink.jdbc.batch-writing" value="Buffered" />
        <property name="eclipselink.target-database" value="MySQL" />
        <property name="eclipselink.jdbc.native-sql" value="false" />
        <property name="eclipselink.logging.level" value="fine" />
        <property name="eclipselink.logging.file"
            value="C:\Users\Vineet\workspace1\MyClassRegister\persistance_logging.txt" />
        <property name="eclipselink.application-location" value="C:\Users\Vineet\workspace1\MyClassRegister" />
        <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/testing124"/>
        <property name="javax.persistence.jdbc.user" value="root"/>
        <property name="javax.persistence.jdbc.password" value="test"/>
        <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
    </properties>
</persistence-unit>

的applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:repository="http://www.springframework.org/schema/data/repository"
xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
        http://www.springframework.org/schema/data/jpa
        http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd 
        http://www.springframework.org/schema/jdbc
        http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
        http://www.springframework.org/schema/data/repository
        http://www.springframework.org/schema/data/repository/spring-repository-1.5.xsd">

<context:component-scan base-package="com.myclassregister.model" />

<context:annotation-config/>

<bean id="datasource"
    class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://localhost:3306/testing124" />
    <property name="username" value="root" />
    <property name="password" value="test" />
</bean>

<bean id="jpaDialect"
    class="org.springframework.orm.jpa.vendor.EclipseLinkJpaDialect" />

<bean id="entityManagerFactory"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="datasource" />
    <property name="persistenceUnitName" value="MyClassRegister" />
    <property name="jpaDialect" ref="jpaDialect" />
    <property name="jpaVendorAdapter">
        <bean
            class="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter" />
    </property>
    <property name="loadTimeWeaver">
        <bean
            class="org.springframework.instrument.classloading.SimpleLoadTimeWeaver" />
    </property>
</bean>

<bean id="helloWorld"
    class="com.myclassregister.model.test.TestGetSchoolListActivity" />

<jpa:repositories base-package="com.myclassregister.model.repository"></jpa:repositories>

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

<bean id="loadTimeWeaver" class="com.myclassregister.utils.JpaAwareLoadTimeWeaver" />

<bean
    class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

</beans>

SchoolRepository.java

@Repository
public interface SchoolRepository 
extends JpaRepository <School,Long> {

public School findById(Long Id);

public Collection<School> findAllSchools();

}

GetSchoolListActivity.java

 @Service
 public final class GetSchoolListActivity {

private static final String PERSISTENCE_UNIT_NAME = "MyClassRegister";
private static EntityManagerFactory factory;

@Autowired  
SchoolRepository schoolRepository;

@Transactional(readOnly=true)
public Collection<School> GetSchools () {

    factory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
    EntityManager em = factory.createEntityManager();

    JpaRepositoryFactory jpaRepositoryFactory = new JpaRepositoryFactory(em);

        schoolRepository = jpaRepositoryFactory.getRepository(SchoolRepository.class);

    Collection<School> schools = new ArrayList <School> ();
    try{
        schools = schoolRepository.findAllSchools();
    }
    catch(Exception e){
    }
    return schools;
}   
}

堆栈跟踪

Exception in thread "main" org.springframework.data.mapping.PropertyReferenceException: No property find found for type com.myclassregister.model.base.misc.School
at org.springframework.data.mapping.PropertyPath.<init>(PropertyPath.java:75)
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:327)
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:353)
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:353)
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:307)
at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:271)
at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:245)
at org.springframework.data.repository.query.parser.Part.<init>(Part.java:73)
at org.springframework.data.repository.query.parser.PartTree$OrPart.<init>(PartTree.java:180)
at org.springframework.data.repository.query.parser.PartTree$Predicate.buildTree(PartTree.java:260)
at org.springframework.data.repository.query.parser.PartTree$Predicate.<init>(PartTree.java:240)
at org.springframework.data.repository.query.parser.PartTree.<init>(PartTree.java:68)
at org.springframework.data.jpa.repository.query.PartTreeJpaQuery.<init>(PartTreeJpaQuery.java:57)
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$CreateQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:90)
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$CreateIfNotFoundQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:162)
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$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.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:116)
at com.myclassregister.api.login.GetSchoolListActivity.GetSchools(GetSchoolListActivity.java:35)
at com.myclassregister.model.test.TestGetSchoolListActivity.main(TestGetSchoolListActivity.java:12)

Answer 1

我遇到了麻烦，因为该实体没有任何专栏＆＃34; ID＆＃34; （它的SchoolID）和存储库有一个方法findByID，它抛出错误。

Answer 2

在创建entityManagerFactory时，您需要指定您的域类。在配置中添加以下属性：

<property name="packagesToScan" value="com.abc.model"/>

在您在此处粘贴的堆栈跟踪中，它表示无法映射/识别School类。一旦你包含上面的属性，它应该工作

自动装配的JpaRepository始终为null

2 个答案: