如何使用Spring数据弹性搜索提供突出显示

Question

似乎SpringData ES不提供类来获取ES返回的高亮显示。 Spring Data可以返回对象列表，但ES返回的Json中的突出显示部分位于“ElasticSearchTemplate”类未处理的独立部分中。

代码示例： -

QueryBuilder query = QueryBuilders.matchQuery("name","tom"); 
SearchQuery searchQuery =new NativeSearchQueryBuilder().withQuery(query).
                               with HighlightFields(new Field("name")).build();
List<ESDocument> publications = elasticsearchTemplate.queryForList
                                                (searchQuery, ESDocument.class);

我一定是错的，但我不知道只能用SpringDataES做什么。有人可以发布一个如何使用Spring Data ES获得亮点的示例吗？

提前致谢 ！

Answer 1

从spring数据弹性搜索中的测试用例中我找到了解决方案：

这可能会有所帮助。

@Test
public void shouldReturnHighlightedFieldsForGivenQueryAndFields() {

    //given
    String documentId = randomNumeric(5);
    String actualMessage = "some test message";
    String highlightedMessage = "some <em>test</em> message";

    SampleEntity sampleEntity = SampleEntity.builder().id(documentId)
            .message(actualMessage)
            .version(System.currentTimeMillis()).build();

    IndexQuery indexQuery = getIndexQuery(sampleEntity);

    elasticsearchTemplate.index(indexQuery);
    elasticsearchTemplate.refresh(SampleEntity.class);

    SearchQuery searchQuery = new NativeSearchQueryBuilder()
            .withQuery(termQuery("message", "test"))
            .withHighlightFields(new HighlightBuilder.Field("message"))
            .build();

    Page<SampleEntity> sampleEntities = elasticsearchTemplate.queryForPage(searchQuery, SampleEntity.class, new SearchResultMapper() {
        @Override
        public <T> Page<T> mapResults(SearchResponse response, Class<T> clazz, Pageable pageable) {
            List<SampleEntity> chunk = new ArrayList<SampleEntity>();
            for (SearchHit searchHit : response.getHits()) {
                if (response.getHits().getHits().length <= 0) {
                    return null;
                }
                SampleEntity user = new SampleEntity();
                user.setId(searchHit.getId());
                user.setMessage((String) searchHit.getSource().get("message"));
                user.setHighlightedMessage(searchHit.getHighlightFields().get("message").fragments()[0].toString());
                chunk.add(user);
            }
            if (chunk.size() > 0) {
                return new PageImpl<T>((List<T>) chunk);
            }
            return null;
        }
    });

    assertThat(sampleEntities.getContent().get(0).getHighlightedMessage(), is(highlightedMessage));
}

Answer 2

实际上，您可以使用自定义ResultExtractor执行以下操作：

QueryBuilder query = QueryBuilders.matchQuery("name", "tom"); 
SearchQuery searchQuery = new NativeSearchQueryBuilder()
                           .withQuery(query)
                           .withHighlightFields(new Field("name")).build();
return elasticsearchTemplate.query(searchQuery.build(), new CustomResultExtractor());

然后

public class CustomResultExtractor implements ResultsExtractor<List<MyClass>> {

private final DefaultEntityMapper defaultEntityMapper;

public CustomResultExtractor() {
    defaultEntityMapper = new DefaultEntityMapper();
}


@Override
public List<MyClass> extract(SearchResponse response) {
    return StreamSupport.stream(response.getHits().spliterator(), false) 
        .map(this::searchHitToMyClass) 
        .collect(Collectors.toList());
}

private MyClass searchHitToMyClass(SearchHit searchHit) {
    MyElasticSearchObject myObject;
    try {
        myObject = defaultEntityMapper.mapToObject(searchHit.getSourceAsString(), MyElasticSearchObject.class);
    } catch (IOException e) {
        throw new ElasticsearchException("failed to map source [ " + searchHit.getSourceAsString() + "] to class " + MyElasticSearchObject.class.getSimpleName(), e);
    }
    List<String> highlights = searchHit.getHighlightFields().values()
        .stream() 
        .flatMap(highlightField -> Arrays.stream(highlightField.fragments())) 
        .map(Text::string) 
        .collect(Collectors.toList());
    // Or whatever you want to do with the highlights
    return new MyClass(myObject, highlights);
}}

请注意，我使用了一个列表，但您可以使用任何其他可迭代的数据结构。此外，你可以用亮点做其他事情。在这里，我只是列出它们。