spring中应用模板模式封装ElasticsearchTemplate

1.查询
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@Override
public <T> FacetedPage<T> queryForPage(SearchQuery query, Class<T> clazz, SearchResultMapper mapper) {
    SearchResponse response = doSearch(prepareSearch(query, clazz), query);
    return mapper.mapResults(response, clazz, query.getPageable());
}

主要逻辑在doSearch方法中

private SearchResponse doSearch(SearchRequestBuilder searchRequest, SearchQuery searchQuery) {
    if (searchQuery.getFilter() != null) {
        searchRequest.setPostFilter(searchQuery.getFilter());
    } 

    if (CollectionUtils.isNotEmpty(searchQuery.getElasticsearchSorts())) {
        for (SortBuilder sort : searchQuery.getElasticsearchSorts()) {
            searchRequest.addSort(sort);
        }
    } 

    if (CollectionUtils.isNotEmpty(searchQuery.getFacets())) {
        for (FacetRequest facetRequest : searchQuery.getFacets()) {
            FacetBuilder facet = facetRequest.getFacet();
            if (facetRequest.applyQueryFilter() && searchQuery.getFilter() != null) {
                facet.facetFilter(searchQuery.getFilter());
            }
            searchRequest.addFacet(facet);
        }
    } 

    if (searchQuery.getHighlightFields() != null) {
        for (HighlightBuilder.Field highlightField : searchQuery.getHighlightFields()) {
            searchRequest.addHighlightedField(highlightField);
        }
    } 

    if (CollectionUtils.isNotEmpty(searchQuery.getAggregations())) {
        for (AbstractAggregationBuilder aggregationBuilder : searchQuery.getAggregations()) {
            searchRequest.addAggregation(aggregationBuilder);
        }
    }
    return getSearchResponse(searchRequest.setQuery(searchQuery.getQuery()).execute());
}

该方法主要处理逻辑

1.加入顺序参数

2.设置参数过滤参数

3.设置高亮显示参数

结果处理由组件?ResultsMapper 结果映射器处理

public interface ResultsMapper extends SearchResultMapper, GetResultMapper, MultiGetResultMapper {

EntityMapper getEntityMapper();

}
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public interface SearchResultMapper {

<T> FacetedPage<T> mapResults(SearchResponse response, Class<T> clazz, Pageable pageable);

}
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初始化映射器

public ElasticsearchTemplate(Client client, ElasticsearchConverter elasticsearchConverter, ResultsMapper resultsMapper) {
this.client = client;
this.elasticsearchConverter = (elasticsearchConverter == null) ? new MappingElasticsearchConverter(
new SimpleElasticsearchMappingContext()) : elasticsearchConverter;
this.resultsMapper = (resultsMapper == null) ? new DefaultResultMapper(this.elasticsearchConverter.getMappingContext()) : resultsMapper;
}
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默认实现的映射器DefaultResultMapper

@Override
public <T> FacetedPage<T> mapResults(SearchResponse response, Class<T> clazz, Pageable pageable) {
    long totalHits = response.getHits().totalHits();
    List<T> results = new ArrayList<T>();
    for (SearchHit hit : response.getHits()) {
        if (hit != null) {
            T result = null;
            if (!Strings.isNullOrEmpty(hit.sourceAsString())) {
                result = mapEntity(hit.sourceAsString(), clazz);
            } else {
                result = mapEntity(hit.getFields().values(), clazz);
            }
            setPersistentEntityId(result, hit.getId(), clazz);
            results.add(result);
        }
    }
    List<FacetResult> facets = new ArrayList<FacetResult>();
    if (response.getFacets() != null) {
        for (Facet facet : response.getFacets()) {
            FacetResult facetResult = DefaultFacetMapper.parse(facet);
            if (facetResult != null) {
                facets.add(facetResult);
            }
        }
    } 

    return new FacetedPageImpl<T>(results, pageable, totalHits, facets);
}

主要是讲json格式转换为指定Class类型bean对象

##2.自主扩展

搜索逻辑绝大部分可以固化封装，只有结果处理需要留出用户扩展空间，可以用回调的方式，定义接口，参数中传入匿名实现

@Override
public <T> T query(SearchQuery query, ResultsExtractor<T> resultsExtractor) {
SearchResponse response = doSearch(prepareSearch(query), query);
return resultsExtractor.extract(response);
}
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public interface ResultsExtractor<T> {