【Elasticsearch】06-JavaRestClient查询

1. MatchAll查询与结果解析

public class ElasticQueryTest {
    private RestHighLevelClient client;

    @BeforeEach
    public void init() {
        client = new RestHighLevelClient(RestClient.builder(
                HttpHost.create("http://nuaamvp.cn:9200")
        ));
    }

    @AfterEach
    void tearDown() {
        if (client!=null) {
            try {
                client.close();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
    }

    @Test
    void testMatchAll() throws IOException {
        // 1. 创建 Request
        SearchRequest request = new SearchRequest("items");
        // 2. 组织请求参数
        request.source().query(
                QueryBuilders.matchAllQuery()
        );
        // 3. 发送请求
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        // 4. 解析响应
        handleResponse(response);
    }
    public void handleResponse(SearchResponse response) {
        SearchHits searchHits = response.getHits();
        // 1. 获取总条数
        long total = searchHits.getTotalHits().value;
        System.out.println("共搜索到" + total + "条记录");
        // 2. 遍历结果数组
        SearchHit[] hits = searchHits.getHits();
        for(SearchHit hit:hits) {
            // 3. 得到原始 json 文档 _source
            String source = hit.getSourceAsString();
            // 4. 反序列化打印
            ItemDoc itemDoc = JSONUtil.toBean(source, ItemDoc.class);
            System.out.println(itemDoc);
        }
    }
}

2. 复合查询

分页、排序。

    @Test
    void testMatch() throws IOException {
        // 1. 创建 Request
        SearchRequest request = new SearchRequest("items");

        // 2. 组织请求参数
        request.source().query(
                // QueryBuilders.multiMatchQuery("牛奶", "name", "category")
                // QueryBuilders.matchQuery("name", "智能手机")
                QueryBuilders.boolQuery()
                        .must(QueryBuilders.matchQuery("name", "脱脂牛奶"))
                        .filter(QueryBuilders.termQuery("brand", "德"))
                        .filter(QueryBuilders.rangeQuery("price").lt(30000))
        );
        // 3. 发送请求
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        // 4. 解析响应
        handleResponse(response);
    }

3. 高亮

    @Test
    void testMatch() throws IOException {
        // 0. 前端参数
        int pageNo = 1, pageSize = 5;

        // 1. 创建 Request
        SearchRequest request = new SearchRequest("items");

        // 2. 组织请求参数
        request.source().query(
                // QueryBuilders.multiMatchQuery("牛奶", "name", "category")
                // QueryBuilders.matchQuery("name", "智能手机")
                QueryBuilders.boolQuery()
                        .must(QueryBuilders.matchQuery("name", "脱脂牛奶"))
                        .filter(QueryBuilders.termQuery("brand", "德"))
                        .filter(QueryBuilders.rangeQuery("price").lt(30000))
        );
        // 2.1 分页
        request.source().from((pageNo-1)*pageSize).size(pageSize);
        // 2.2 排序
        request.source()
                .sort("sold", SortOrder.ASC)
                .sort("price", SortOrder.DESC);
        // 2.3 高亮
        request.source().highlighter(
                SearchSourceBuilder.highlight()
                        .field("name")
                        .preTags("<em>")
                        .postTags("</em>")
        );
        // 3. 发送请求
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        // 4. 解析响应
        handleResponse(response);
    }

将高亮结果解析出来。

public void handleResponse(SearchResponse response) {
        SearchHits searchHits = response.getHits();
        // 1. 获取总条数
        long total = searchHits.getTotalHits().value;
        System.out.println("共搜索到" + total + "条记录");
        // 2. 遍历结果数组
        SearchHit[] hits = searchHits.getHits();
        for(SearchHit hit:hits) {
            // 3. 得到原始 json 文档 _source
            String source = hit.getSourceAsString();
            // 4. 反序列化打印
            ItemDoc itemDoc = JSONUtil.toBean(source, ItemDoc.class);
            // 5. 获取高亮结果
            Map<String, HighlightField> hfs = hit.getHighlightFields();
            if (CollUtils.isNotEmpty(hfs)) {
                // 5.1 获取name的高亮结果
                HighlightField hf = hfs.get("name");
                if (hf!=null) {
                    String hfName = hf.getFragments()[0].string();
                    itemDoc.setName(hfName);
                }
            }
            System.out.println(itemDoc);
        }
    }