spring data jpa @Entity property not found 异常

Question

我是 spring-data-jpa 的新手，目前正在尝试使用 hibernate 来实现。我关注了tutorial！为此，我目前面临启动应用程序本身的问题。 在启动过程中出现以下异常：

 Caused by: org.springframework.data.mapping.PropertyReferenceException: No property customer found for type com.adaptris.dashboard.customer.Customer
at org.springframework.data.mapping.PropertyPath.<init>(PropertyPath.java:74)
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:326)
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:352)
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:306)
at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:270)
at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:244)
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$Predicate.<init>(PartTree.java:240)
at org.springframework.data.repository.query.parser.PartTree.<init>(PartTree.java:71)
at org.springframework.data.jpa.repository.query.PartTreeJpaQuery.<init>(PartTreeJpaQuery.java:57)
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$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.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)

客户是我用

注释的域类

@Entity(name = "customer")

我想它正在尝试连接到数据库并获取我实际配置的客户表。这是我的弹簧配置：

<tx:annotation-driven transaction-manager="transactionManager" />
<!-- Activate Spring Data JPA repository support -->
<jpa:repositories base-package="com.adaptris.dashboard.customer" />

    <!-- Declare a datasource that has pooling capabilities -->
<bean id="jpaDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
    destroy-method="close" p:driverClass="${app.jdbc.driverClassName}"
    p:jdbcUrl="${app.jdbc.url}" p:user="${app.jdbc.username}" p:password="${app.jdbc.password}"
    p:acquireIncrement="5" p:idleConnectionTestPeriod="60" p:maxPoolSize="100"
    p:maxStatements="50" p:minPoolSize="10" />

<!-- Declare a JPA entityManagerFactory -->
<bean id="entityManagerFactory"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
    p:persistenceXmlLocation="classpath*:META-INF/persistence.xml"
    p:persistenceUnitName="hibernatePersistenceUnit" p:dataSource-ref="jpaDataSource"
    p:jpaVendorAdapter-ref="hibernateVendor" />

<!-- Specify our ORM vendor -->
<bean id="hibernateVendor"
    class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
    p:showSql="false" />

<!-- Declare a transaction manager -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"
    p:entityManagerFactory-ref="entityManagerFactory" />

数据库是正在运行的 MYSQL。以下是属性：

# database properties
app.jdbc.driverClassName=com.mysql.jdbc.Driver
app.jdbc.url=jdbc\:mysql\://Mallik-PC/adaptrisschema
app.jdbc.username=dbuser
app.jdbc.password=dbpassword

请帮我解决这个问题！！

Answer 1

听起来您为 Domain 类指定的 Repository 接口包含一个 findXXX 方法，而 XXX 不是您的 Domain 类的属性。

例子：

public interface UserRepository extends CrudRepository<User, String> {

    /**
     * Finds a user by name.
     * 
     * @param name The name of the User to find.
     * @return The User with the given name.
     */
    public User findByName(String name);
}

而您的 Domain 类看起来像这样并且缺少“name”属性：

@Entity
public class User {
    private String firstname;
    private String lastname;
    // No "private String name" in here!
    ... 
}

在您的特定示例中，您似乎向您的存储库接口添加了一个findByCustomer(Customer customer) 方法（可能称为CustomerRepository 之类的东西）。您不需要该方法，因为 Spring Data for JPA 会自动为您生成 findOne(<PrimaryKeyClass> id) 方法，您只需使用 Domain 类 Customer 的 @Id 作为参数来调用它。

Answer 2

Spring ORM 的LocalContainerEntityManagerFactoryBean（我认为是 3.1）有一个名为“packagesToScan”的属性。除非您有其他要通过 persistence.xml 设置的供应商属性，否则请删除 p:persistenceXmlLocation 并替换为

p:packagesToScan="[package name where your entities are]"

这告诉LocalContainerEntityManagerFactoryBean 在哪里可以找到您所有的@Entity pojo，并将它们包含在您的 EntityManagerFactory 中，以便 Spring Data JPA 可以找到放置“客户”的位置

Answer 3

在我的例子中，由于 Spring 区分大小写，我遇到了这个错误。我按 firstname 搜索，域类中的声明为 firstName：

@Entity
public class User {
    private String firstName;
...

只是因为 find 方法被声明为 findByFirstname 我得到了这个错误。将字母 n 更改为 N 后即可使用。

public Collection<User> findByFirstName(@Param("firstName") String firstname);