No property found for type error when try to create custom repository with Spring Data JPA

问题

I have a Media entity that has some basic fields for files uploaded by the user. For saving the bytes of the files uploaded, I want to create a custom repository that holds that functionality. Following the steps in the Spring documentation, I've created an interface that looks like this:

public interface MediaBytesRepository
{
    public byte[] getBytes(Media media) throws IOException;
    public void saveBytes(Media media, byte[] bytes) throws IOException;
    public void appendBytes(Media media, byte[] bytes) throws IOException;
    public void deleteBytes(Media media) throws IOException;
    public boolean bytesExist(Media media) throws IOException;
}

Then I provided an implementation for this interface called MediaBytesRepositoryImpl

With this, I then created the following interface:

public interface MediaRepository extends JpaRepository<Media, Long>, MediaBytesRepository
{
}

Now, when I start up the server, I get the following stack trace:

SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mediaRepository': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalArgumentException: Could not create query metamodel for method public abstract void com.foo.bar.core.media.MediaBytesRepository.saveBytes(com.foo.bar.core.media.Media,byte[]) throws java.io.IOException!
    at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:149)
.....
Caused by: java.lang.IllegalArgumentException: Could not create query metamodel for method public abstract void com.foo.bar.core.media.MediaBytesRepository.saveBytes(com.foo.bar.core.media.Media,byte[]) throws java.io.IOException!
    at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$CreateQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:92)
    at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$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)
    ... 20 more
 Caused by: java.lang.IllegalArgumentException: No property save found for type class com.foo.bar.core.media.Media
    at org.springframework.data.mapping.PropertyPath.<init>(PropertyPath.java:73)
    at org.springframework.data.mapping.PropertyPath.<init>(PropertyPath.java:92)
    at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:319)
    at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:333)
    at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:301)
    at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:265)
    at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:239)
    at org.springframework.data.repository.query.parser.Part.<init>(Part.java:70)
    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)
    ... 27 more

I found this similar post, but the suggestions there (all in same package, naming convention) are things I'm already doing. All my media classes and interfaces are in the same package, and I'm using the "Impl" suffix.

Can someone please shed some light on why I'm getting this error and how I can fix it? Thanks.

回答1:

You wrote:

the suggestions there (all in same package, naming convention) are things I'm already doing.

No you do not.

Rename you MediaBytesRepository to MediaRepositoryCustom.

And of course you need an implementation of MediaRepositoryCustom with the name MediaRepositoryImpl.

回答2:

You must name your impl class as "InterfaceNameImpl". Default postfix for implementation is Impl, we can change it as we like:

<repositories base-package="com.acme.repository" repository-impl-postfix="FooBar" />

The name of custom interfaces does not matter.

来源：https://stackoverflow.com/questions/13945490/no-property-found-for-type-error-when-try-to-create-custom-repository-with-sprin