spring中应用模板模式封装ElasticsearchTemplate

Posted 2020-11-24

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()); 
}

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主要逻辑在doSearch方法中

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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()); 
}

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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

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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

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@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); 
}

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主要是讲json格式转换为指定Class类型bean对象

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##2.自主扩展

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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

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@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> {

T extract(SearchResponse response); 

}
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学习视频

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复制链接，在浏览器打开
tomcat源码解析
https://study.163.com/course/introduction/1209535854.htm

Springmvc源码解析
https://study.163.com/course/introduction/1209536851.htm

dubbo源码解析
https://study.163.com/course/introduction/1209648816.htm