找不到java.lang.Object的映射元数据-Couchbase [英] No mapping metadata found for java.lang.Object - Couchbase

问题描述

我将实体保留在CouchBase存储库中，并尝试对其进行查询.实体看起来像这样:

I'm persisting an entity in a CouchBase repository and trying to query it. The entity looks like this:

@Document(expiry = 0)
public class GsJsonStore implements Serializable {
    private static final long serialVersionUID = 7133072282172062535L;
    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    private long id;
    @Field
    private Map<String,Object> _object;
    @Field
    private String _subject;
    @Field
    private String _predicate;
    //Getters and Setters 
    }

我正在使用CouchbaseOperations模板上的N1QL查询来查询实体，如下所示:

I'm querying the entity by using N1QL queries on the CouchbaseOperations template like this:

String query1 =  "SELECT META(default).id as _ID, META(default).cas as _CAS, default.* FROM default WHERE "+key+"="+"'"+value+"'";

List<GsJsonStore> list = operations.findByN1QL(N1qlQuery.simple(query1), GsJsonStore.class);

我正在_object Map中查询K-V对.我收到错误消息:No mapping metadata found for java.lang.Object

I'm querying for a K-V pair within the _object Map. I get an error : No mapping metadata found for java.lang.Object

为什么会这样?此外，我在Couchbase中将json对象存储为Map<String,Object>，我尝试使用jackson JsonNode类型，但是该对象还存储了与类相关的元数据.有没有更好的数据类型来表示json类型?

Why is this happening? Also, I'm storing a json object as Map<String,Object> in Couchbase, I tried using the jackson JsonNode type but the object was also storing class related metadata. Is there a better datatype to represent the json type?

编辑

存储在Couchbase中的数据:

Data stored in Couchbase :

{
"_object" : {
"Name" : "Kapil",
"Age" : {
"Nested" : 21
}
},
"_subject" : "Subject",
"_predicate" : "Predicate"
}

我要查找的键是_object.名称和值是"Kapil"

The key I'm looking for is _object.Name and value is 'Kapil'

推荐答案

如此处您应该覆盖默认的SPMappingCouchbaseConverter.

As explained here you should override the default SPMappingCouchbaseConverter.

这是我解决问题的方法:

Here is how I solved the problem:

@Bean
public MappingCouchbaseConverter mappingCouchbaseConverter() throws Exception {
    return new MyMappingCouchbaseConverter(couchbaseMappingContext());
}

private class MyMappingCouchbaseConverter extends MappingCouchbaseConverter {

    MyMappingCouchbaseConverter(MappingContext<? extends CouchbasePersistentEntity<?>, CouchbasePersistentProperty> mappingContext) {
        super(mappingContext);
    }

    @Override
    @SuppressWarnings("unchecked")
    protected <R> R read(final TypeInformation<R> type, final CouchbaseDocument source, final Object parent) {
        if (Object.class == typeMapper.readType(source, type).getType()) {
            return (R) source.export();
        } else {
            return super.read(type, source, parent);
        }
    }

}

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