无法使用spring数据elasticsearch将_source映射到java对象

Question

我想使用spring数据elasticsearch将elasticsearch文档映射到对象。我的文档包含嵌套对象，但是当我映射它们时，我得到一个空值。

这是我的存储库：

public interface DocumentRepository extends ElasticsearchRepository<Document,String> {
@Query("{\"bool\": {\"must\": [{\"term\": {\"content.content.page\":" +
        " \"item\"}}]}}")
List<Document> getDocumentName(String keyWord, Pageable pageable);

} 这是我的文档：

@Getter
@Setter
@org.springframework.data.elasticsearch.annotations.Document(indexName = "non_omega_scoped",type = "documents")
public class Document {
    @Id
    private String id;
    private String content;

    private Metadata metadata;
    private String scope;
    private String filename;

    public Document() {
    }

    public Document(String id, Metadata metadata, String filename) {
        this.id = id;
        this.metadata = metadata;
        this.filename = filename;
    }

    public String getContent() {
        return content;
    }

主要方法：

 @SpringBootApplication
public class Application implements CommandLineRunner {

    @Autowired
    private ElasticsearchOperations es;
    @Autowired
    DocumentRepository documentRepository;
    public static void main(String args[]) {
        SpringApplication.run(Application.class, args);
    }
    @Override
    public void run(String... args) throws Exception {
        List<Document> documents=documentRepository.getDocumentName("",new PageRequest(0,10));
        documents.forEach(
                (document)-> {
                    System.err.println(document.getId());
                    System.err.println(document.getFilename());
                    System.err.println(document.getScope());
                    System.err.println(document.getMetadata().getYoaNumber());
                }
        );
    }

输出为：

AWWGLKG1r_fC1ssn9Hht
/UW/AH/Policies/C001510K17A/TaxonomyList.xlsx
SGPC
null