ElasticSearch查询

ElasticSearch查询 一、数据准备 1.  客户端对象client创建核心配置文件：ElasticSearchConfig.class

@Configuration
@ConfigurationProperties(prefix = "elasticsearch")
public class ElasticSearchConfig {
    private String host;
    private int port;

    public String getHost() {
        return host;
    }

    public void setHost(String host) {
        this.host = host;
    }

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    @Bean
    public RestHighLevelClient client(){
        return new RestHighLevelClient(RestClient.builder(
                new HttpHost(
                        host,
                        port,
                        "http"
                )
        ));
    }
}

2. 配置文件：application.yml

elasticsearch:
  host: 192.168.23.129
  port: 9200

二、查询

1. 查询全部：matchAll

    // 查询所有
    @Test
    public void matchAll() throws IOException {
        // 2.创建查询请求，并且指定查询的索引库
        SearchRequest searchRequest = new SearchRequest("goods");

        // 4. 创建查询条件对象
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

        // 5.指定具体的查询条件
        QueryBuilder query = QueryBuilders.matchAllQuery();
        sourceBuilder.query(query);
        // 指定分页条件
        sourceBuilder.from(0);
        sourceBuilder.size(100);

        // 3. 设置文档查询条件，需要查询条件对象sourceBuilder
        searchRequest.source(sourceBuilder);

        // 1. 使用客户端对象client执行查询 *** 作，需要一个查询请求
        SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);

        //6. 获取查询结果
        // 6.1 获取第一层hits，得到查询总数
        SearchHits hits = searchResponse.getHits();
        long total = hits.getTotalHits().value;
        System.out.println(total);

        // 6.2 获取第二层hits，得到具体的数据
        SearchHit[] hits1 = hits.getHits();

        // 7. 创建集合，用于存放转换的goods对象
        List goodsList = new ArrayList<>();

        // 6.3 将查询到的数据数组，转换为json字符串，并转换为goods对象
         for (SearchHit hit : hits1) {
            String sourceAsString = hit.getSourceAsString();
            // 转为java对象
            Goods goods = JSON.parseObject(sourceAsString, Goods.class);
            // 添加到集合
            goodsList.add(goods);
        }

         // 遍历集合，输出查询结果
        for (Goods goods : goodsList) {
            System.out.println(goods);
        }
    }

2. term词条查询

// 5.指定具体的查询条件
QueryBuilder query = QueryBuilders.termQuery("title", "华为");
sourceBuilder.query(query);
// 指定分页条件
sourceBuilder.from(0);
sourceBuilder.size(100);

3. match词条分词查询

// 5.指定具体的查询条件
MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("title", "华为手机");
// 定义交并集
matchQueryBuilder.operator(Operator.AND);
sourceBuilder.query(matchQueryBuilder);

4. 模糊查询：wildcard查询

// 5.指定具体的查询条件
QueryBuilder query = QueryBuilders.wildcardQuery("title", "华*");
sourceBuilder.query(query);

5. 模糊查询：正则查询

// 5.指定具体的查询条件
QueryBuilder query = QueryBuilders.regexpQuery("title", "\w(.)*");
sourceBuilder.query(query);

6. 模糊查询：前缀查询

// 5.指定具体的查询条件
QueryBuilder query = QueryBuilders.prefixQuery("brandName", "三");
sourceBuilder.query(query);

7. 范围查询：rangeQuery

// 5.指定具体的查询条件  范围查询
RangeQueryBuilder query = QueryBuilders.rangeQuery("price");
// 指定下限
query.gte(2000);
// 指定上限
query.lte(3000);
sourceBuilder.query(query);

// 对查询结果进行排序
sourceBuilder.sort("price", SortOrder.ASC);

8. 多字段查询：queryStringQuery

 // 5.指定具体的查询条件  范围查询
QueryStringQueryBuilder query = QueryBuilders
        .queryStringQuery("华为手机")                     
        .field("title")
        .field("categoryName")
        .field("brandName")
        .defaultOperator(Operator.AND);
sourceBuilder.query(query);

9. 多条件查询

// 5.指定具体的查询条件  bool查询
BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();

TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("brandName", "华为");
boolQueryBuilder.must(termQueryBuilder);

MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("title", "手机");
boolQueryBuilder.filter(matchQueryBuilder);

RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("price");
rangeQueryBuilder.gte(2000);
rangeQueryBuilder.lte(3000);
boolQueryBuilder.filter(rangeQueryBuilder);

sourceBuilder.query(boolQueryBuilder);

10. 聚合查询：

        // 5.指定具体的查询条件  聚合查询
        // 5.1 查询
        MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("title", "手机");
        sourceBuilder.query(matchQueryBuilder);

        // 5.2 聚合
        AggregationBuilder aggregation = AggregationBuilders.terms("goods_brands")
                                        .field("brandName").size(100);
        sourceBuilder.aggregation(aggregation);


        //6. 获取查询结果
        // 6.1 获取第一层hits，得到查询总数
        SearchHits hits = searchResponse.getHits();
        long total = hits.getTotalHits().value;
        System.out.println(total);

        // 6.2 获取第二层hits，得到具体的数据
        SearchHit[] hits1 = hits.getHits();

        // 7. 创建集合，用于存放转换的goods对象
        List goodsList = new ArrayList<>();

        // 6.3 将查询到的数据数组，转换为json字符串，并转换为goods对象
        for (SearchHit hit : hits1) {
            String sourceAsString = hit.getSourceAsString();
            // 转为java对象
            Goods goods = JSON.parseObject(sourceAsString, Goods.class);
            // 添加到集合
            goodsList.add(goods);
        }

        // 遍历集合，输出查询结果
        for (Goods goods : goodsList) {
            System.out.println(goods);
        }

        // 获取聚合结果
        Aggregations aggregations = searchResponse.getAggregations();
        // 将json字符串转成map对象
        Map aggregationMap = aggregations.asMap();

        Terms goods_brands = (Terms) aggregationMap.get("goods_brands");
        List buckets = goods_brands.getBuckets();

        List brands = new ArrayList();
        for (Terms.Bucket bucket : buckets) {
            Object key = bucket.getKey();
            brands.add(key);
        }

        for (Object brand : brands) {
            System.out.println(brand);
        }

11. 高亮查询

        // 5.1 查询
        MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("title", "手机");
        sourceBuilder.query(matchQueryBuilder);

        // 5.2 设置高亮
        HighlightBuilder highlighter = new HighlightBuilder();
        // 设置三要素
        highlighter.field("title");
        highlighter.preTags("");
        highlighter.postTags("");
        sourceBuilder.highlighter(highlighter);

         // 6.3 将查询到的数据数组，转换为json字符串，并转换为goods对象
        for (SearchHit hit : hits) {
            String sourceAsString = hit.getSourceAsString();
            // 转为java对象
            Goods goods = JSON.parseObject(sourceAsString, Goods.class);

            // 获取高亮结果
            Map highlightFields = hit.getHighlightFields();
            // 根据关键字title获得数组
            HighlightField highlightField = highlightFields.get("title");
            // 获取片段？？
            Text[] fragments = highlightField.fragments();
            // 替换
            goods.setTitle(fragments[0].toString());

            // 添加到集合
            goodsList.add(goods);
        }