DynamoDB Spring Boot数据休息“PersistentEntity不能为空！”

Question

I am building a Spring Boot application with DynamoDB. I wanted to add Spring Data REST. The data layer works, but the REST fails on mapping of the entities. It correctly resolves and creates the REST endpoint but I am getting PersistentEntity must not be null! message and an exception when accessing the REST API:

java.lang.IllegalArgumentException: PersistentEntity must not be null!
    at org.springframework.util.Assert.notNull(Assert.java:115)
    at org.springframework.data.rest.webmvc.PersistentEntityResource$Builder.<init>(PersistentEntityResource.java:140)
    at org.springframework.data.rest.webmvc.PersistentEntityResource$Builder.<init>(PersistentEntityResource.java:123)
    at org.springframework.data.rest.webmvc.PersistentEntityResource.build(PersistentEntityResource.java:115)
    at org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler.wrap(PersistentEntityResourceAssembler.java:74)
    at org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler.toResource(PersistentEntityResourceAssembler.java:55)
    at org.springframework.data.rest.webmvc.AbstractRepositoryRestController.entitiesToResources(AbstractRepositoryRestController.java:133)
    at org.springframework.data.rest.webmvc.AbstractRepositoryRestController.toResources(AbstractRepositoryRestController.java:80)
    at org.springframework.data.rest.webmvc.RepositoryEntityController.getCollectionResource(RepositoryEntityController.java:212)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)

removed irrelevant parts of the exception

When I debug the code, I see that the entities in PersistentEntityResourceAssembler is empty. It means my entities were not registered. I guess this is because they are not regular JPA entities and they are only linked through the repositories to the data layer.

How do I let Spring know about my entities in order to make the Data REST framework work with DynamoDB?

Here are relevant parts from my project. The dummy entity representing a table in dynamo:

@DynamoDBTable(tableName = "DummyTable")
public class Tester {
    @Id
    private String id;


    @DynamoDBHashKey(attributeName = "id")
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }
}

The repository:

public interface TesterRepository extends CrudRepository<Tester, String> {

    @EnableScan
    @Override
    Iterable<Tester> findAll();
}

The config class:

@Configuration
@EnableDynamoDBRepositories(basePackages = "com.czequered.promocodes.repository")
public class DynamoDBConfig {

// deleted params

    @Bean
    public AmazonDynamoDB amazonDynamoDB() {
// deleted the simple initializer, just long code
        return amazonDB;
    }

}

And gradle dependencies:

compile 'com.amazonaws:aws-java-sdk-core:1.11.86'
compile 'org.springframework.boot:spring-boot-starter'
compile 'org.springframework.boot:spring-boot-starter-data-rest'
compile 'com.github.derjust:spring-data-dynamodb:4.4.1'

The code has been simplified, the rest can be found in this gist with all files needed to build the whole application .

I tried to follow the demo from the original author of the Spring Data DynamoDB library , but it adds JPA and Hibernate to the classpath which I want to avoid as I should not need any of it.

Answer 1

I also developed app with spring boot and dynamo db but I never face this issue . While developing application I refer below example.

Git Dynamo db Spring Boot Spring Data Example