从静态ThreadLocal变量更改Spring数据存储库的Mongo集合是否安全？

Question

I wanted to use Spring Data Mongo repositories and specify collection of the document at runtime. I found the way how I can achieve it in this ticket DATAMONGO-525 and what I did:

Created GenericObject with ThreadLocal variable and linked collection name with this static variable:

@Data
@Document(collection = "#{T(com.test.myproject.model.GenericObject).getCollection()}")
public class GenericObject {

    private static ThreadLocal<String> collection = new ThreadLocal<>();

    @Id
    private ObjectId id;

    private org.bson.Document doc;

    public static void setCollection(String type) {
        collection.set(type);
    }

    public static String getCollection() {
        return collection.get();
    }

}

I created GenericRepository for GenericObject:

public interface GenericObjectRepository extends MongoRepository<GenericObject, ObjectId> {
}

So, now when I want to get/save/delete GenericObject from specific collection I should specify collection before each request:

// save
GenericObject obj = new GenericObject();
GenericObject.setCollection(collectionName);
genericObjectRepository.save(obj)
...
//get
GenericObject.setCollection(collectionName);
genericObjectRepository.findById(new ObjectId(id))
                    .orElseThrow(() -> new RecordNotFoundException("GOS00001", id, collection));

The question is:

Is my approach is thread safe? Are there any issues that I don't see?

SpringDataMongoDB version: 2.0.5.RELEASE

Answer 1

Sounds like you're almost better off just using MongoOperations directly. Why bother with worrying with ThreadLocal . If you want to see more info about static ThreadLocal usage you can refer to this question: Java ThreadLocal static? But yeah you're approach is fine. ThreadLocal is safe to use as a different thread can't set ThreadLocal of another thread.