Es的java API客戶端

在Es7.15版本之后，es官方將它的高級(jí)客戶端RestHighLevelClient標(biāo)記為棄用狀態(tài)。同時(shí)推出了全新的java API客戶端Elasticsearch Java API Client，該客戶端也將在Elasticsearch8.0及以后版本中成為官方推薦使用的客戶端。

Elasticsearch Java API Client支持除Vector title search API和Find structure API之外的所有Elasticsearch API。且支持所有API數(shù)據(jù)類型，并且不再有原始JSON Value屬性。它是針對Elasticsearch8.0及之后版本的客戶端。

感興趣的小伙伴可以去官方文檔看看：Elasticsearch官網(wǎng)8.x版本下Java客戶端文檔

Elasticsearch Java API Client使用

• 新建maven項(xiàng)目

• maven中引入依賴坐標(biāo)

        <dependency>
            <groupId>co.elastic.clients</groupId>
            <artifactId>elasticsearch-java</artifactId>
            <version>8.1.0</version>
        </dependency>
         <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.1</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
            <scope>provided</scope>
        </dependency>

• 創(chuàng)建連接

    @Test
    public void create() throws IOException {
        // 創(chuàng)建低級(jí)客戶端
        RestClient restClient = RestClient.builder(
                new HttpHost("localhost", 9200)
        ).build();
        // 使用Jackson映射器創(chuàng)建傳輸層
        ElasticsearchTransport transport = new RestClientTransport(
                restClient, new JacksonJsonpMapper()
        );
        // 創(chuàng)建API客戶端
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 關(guān)閉ES客戶端
        transport.close();
        restClient.close();
    }

索引index的基本語法

• 創(chuàng)建索引

    @Test
    public void create() throws IOException {
        // 創(chuàng)建低級(jí)客戶端
        RestClient restClient = RestClient.builder(
                new HttpHost("localhost", 9200)
        ).build();
        // 使用Jackson映射器創(chuàng)建傳輸層
        ElasticsearchTransport transport = new RestClientTransport(
                restClient, new JacksonJsonpMapper()
        );
        // 創(chuàng)建API客戶端
        ElasticsearchClient client = new ElasticsearchClient(transport);
        // 創(chuàng)建索引
        CreateIndexResponse createIndexResponse = client.indices().create(c -> c.index("user_test"));
        // 響應(yīng)狀態(tài)
        Boolean acknowledged = createIndexResponse.acknowledged();
        System.out.println("索引操作 = " + acknowledged);

        // 關(guān)閉ES客戶端
        transport.close();
        restClient.close();
    }

• 查詢索引

    @Test
    public void query() throws IOException {
        RestClient restClient = RestClient.builder(
                new HttpHost("localhost",9200)
        ).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 查詢索引
        GetIndexResponse getIndexResponse = client.indices().get(e -> e.index("user_test"));
        System.out.println("getIndexResponse.result() = " + getIndexResponse.result());
        System.out.println("getIndexResponse.result().keySet() = " + getIndexResponse.result().keySet());

        transport.close();
        restClient.close();
    }

如果查詢的index不存在會(huì)在控制臺(tái)拋出index_not_found_exception

• 刪除索引

    @Test
    public void delete() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 刪除索引
        DeleteIndexResponse deleteIndexResponse = client.indices().delete(e -> e.index("user_test"));
        System.out.println("刪除操作 = " + deleteIndexResponse.acknowledged());

        transport.close();
        restClient.close();
    }

文檔document的操作

• 創(chuàng)建User對象

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private String name;
    private String sex;
    private Integer age;
}

• 添加document

    @Test
    public void addDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 向user對象中添加數(shù)據(jù)
        User user = new User("java客戶端", "男", 18);
        // 向索引中添加數(shù)據(jù)
        CreateResponse createResponse = client.create(e -> e.index("user_test").id("1001").document(user));
        System.out.println("createResponse.result() = " + createResponse.result());

        transport.close();
        restClient.close();
    }

注：index中參數(shù)為文檔所屬的索引名，id中參數(shù)為當(dāng)文檔的id，document為文檔數(shù)據(jù)，新版本支持直接傳入java對象。

• 查詢document

    @Test
    public void queryDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 構(gòu)建請求
        GetResponse<User> getResponse = client.get(e -> e.index("user_test").id("1001"), User.class);
        System.out.println("getResponse.source().toString() = " + getResponse.source().toString());

        transport.close();
        restClient.close();
    }

注：如果查不到控制臺(tái)拋出NullPointerException

• 修改document

    @Test
    public void modifyDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 使用map集合封裝需要修改的內(nèi)容
        Map<String, Object> map = new HashMap<>();
        map.put("name", "java客戶端aaa");
        // 構(gòu)建請求
        UpdateResponse<User> updateResponse = client.update(e -> e.index("user_test").id("1001").doc(map), User.class);
        System.out.println("updateResponse.result() = " + updateResponse.result());

        transport.close();
        restClient.close();
    }

• 刪除document

    @Test
    public void removeDocument() throws  IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 構(gòu)建請求
        DeleteResponse deleteResponse = client.delete(e -> e.index("user_test").id("1001"));
        System.out.println("deleteResponse.result() = " + deleteResponse.result());

        transport.close();
        restClient.close();
    }

• 批量添加document

    @Test
    public void batchAddDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 構(gòu)建一個(gè)批量數(shù)據(jù)集合
        List<BulkOperation> list = new ArrayList<>();
        list.add(new BulkOperation.Builder().create(
                d -> d.document(new User("test2", "男", 19)).id("1002").index("user_test")).build());
        list.add(new BulkOperation.Builder().create(
                d -> d.document(new User("test3", "男", 20)).id("1003").index("user_test")).build());
        list.add(new BulkOperation.Builder().create(
                d -> d.document(new User("test4", "女", 21)).id("1004").index("user_test")).build());
        // 調(diào)用bulk方法執(zhí)行批量插入操作
        BulkResponse bulkResponse = client.bulk(e -> e.index("user_test").operations(list));
        System.out.println("bulkResponse.items() = " + bulkResponse.items());

        transport.close();
        restClient.close();
    }

批量添加的核心是需要構(gòu)建一個(gè)泛型為BulkOperation的ArrayList集合，實(shí)質(zhì)上是將多個(gè)請求包裝到一個(gè)集合中，進(jìn)行統(tǒng)一請求，進(jìn)行構(gòu)建請求時(shí)調(diào)用bulk方法，實(shí)現(xiàn)批量添加效果。

• 批量刪除

    @Test
    public void batchDeleteDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 構(gòu)建一個(gè)批量數(shù)據(jù)集合
        List<BulkOperation> list = new ArrayList<>();
        list.add(new BulkOperation.Builder().delete(
                d -> d.id("1002").index("user_test")).build());
        list.add(new BulkOperation.Builder().delete(
                d -> d.id("1003").index("user_test")).build());
        // 調(diào)用bulk方法執(zhí)行批量插入操作
        BulkResponse bulkResponse = client.bulk(e -> e.index("user_test").operations(list));
        System.out.println("bulkResponse.items() = " + bulkResponse.items());

        transport.close();
        restClient.close();
    }

• 全量查詢

    @Test
    public void queryAllDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 全量查詢
        SearchResponse<User> searchResponse = client.search(e -> e.index("user_test").query(q -> q.matchAll(m -> m)), User.class);
        HitsMetadata<User> hits = searchResponse.hits();
        for (Hit<User> hit : hits.hits()) {
            System.out.println("user = " + hit.source().toString());
        }
        System.out.println("searchResponse.hits().total().value() = " + searchResponse.hits().total().value());

        transport.close();
        restClient.close();
    }

• 分頁查詢

    @Test
    public void pagingQueryDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 分頁查詢
        SearchResponse<User> searchResponse = client.search(
                s -> s.index("user_test")
                        .query(q -> q.matchAll(m -> m))
                        .from(2)
                        .size(2)
                , User.class);
        searchResponse.hits().hits().forEach(h -> System.out.println(h.source().toString()));

        transport.close();
        restClient.close();
    }

分頁查詢就是在全量查詢的基礎(chǔ)上增加了從第幾條開始，每頁顯示幾條

• 排序查詢

    @Test
    public void sortQueryDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 排序查詢
        SearchResponse<User> searchResponse = client.search(
                s -> s.index("user_test")
                        .query(q -> q.matchAll(m -> m))
                        .sort(o -> o.field(f -> f.field("age").order(SortOrder.Asc)))
                , User.class);
        searchResponse.hits().hits().forEach(h -> System.out.println(h.source().toString()));

        transport.close();
        restClient.close();
    }

• 條件查詢

    @Test
    public void conditionQueryDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 條件查詢
        SearchResponse<User> searchResponse = client.search(
                s -> s.index("user_test").query(q -> q.matchAll(m -> m))
                        .sort(o -> o.field(f -> f.field("age").order(SortOrder.Asc)))
                        .source(r -> r.filter(f -> f.includes("name", "age").excludes("")))
                , User.class);
        searchResponse.hits().hits().forEach(h -> System.out.println(h.source().toString()));

        transport.close();
        restClient.close();
    }

includes是顯示的字段，excludes是排除的字段

• 組合查詢

    @Test
    public void combinationQueryDocument() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 組合查詢
        SearchResponse<User> searchResponse = client.search(
                s -> s.index("user_test").query(q -> q.bool(b -> b
                        .must(m -> m.match(u -> u.field("age").query(21)))
                        .must(m -> m.match(u -> u.field("sex").query("男")))
                        .mustNot(m -> m.match(u -> u.field("sex").query("女")))
                ))
                , User.class);
        searchResponse.hits().hits().forEach(h -> System.out.println(h.source().toString()));

        transport.close();
        restClient.close();
    }

    @Test
    public void combinationQueryDocument2() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 組合查詢
        SearchResponse<User> searchResponse = client.search(
                s -> s.index("user_test").query(q -> q.bool(b -> b
                        .should(h -> h.match(u -> u.field("age").query(19)))
                        .should(h -> h.match(u -> u.field("sex").query("男")))
                ))
                , User.class);
        searchResponse.hits().hits().forEach(h -> System.out.println(h.source().toString()));

        transport.close();
        restClient.close();
    }

must是必須滿足所有條件，should只要滿足一個(gè)就行

• 范圍查詢

    @Test
    public void scopeQueryDocument2() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 范圍查詢，gte()表示取大于等于，gt()表示大于，lte()表示小于等于
        SearchResponse<User> searchResponse = client.search(s -> s.index("user_test").query(q -> q
                        .range(r -> r.field("age").gte(JsonData.of(20)).lt(JsonData.of(21))))
                , User.class);
        searchResponse.hits().hits().forEach(h -> System.out.println(h.source().toString()));

        transport.close();
        restClient.close();
    }

• 模糊查詢

    @Test
    public void fuzzyQueryDocument2() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 模糊查詢，fuzziness表示差幾個(gè)可以查詢出來
        SearchResponse<User> searchResponse = client.search(s -> s.index("user_test").query(q -> q
                        .fuzzy(f -> f.field("name").value("tst").fuzziness("2")))
                , User.class);
        searchResponse.hits().hits().forEach(h -> System.out.println(h.source().toString()));

        transport.close();
        restClient.close();
    }

• 高亮查詢

    @Test
    public void highlightQueryDocument2() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 高亮查詢
        SearchResponse<User> searchResponse = client.search(s -> s.index("user_test").query(q -> q
                        .term(t -> t.field("name").value("test3")))
                        .highlight(h -> h.fields("name", f -> f.preTags("<font color='red'>").postTags("</font>")))
                , User.class);
        searchResponse.hits().hits().forEach(h -> System.out.println(h.source().toString()));

        transport.close();
        restClient.close();
    }

• 聚合查詢

    @Test
    public void aggregateQueryDocument2() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 聚合查詢，取最大年齡
        SearchResponse<User> searchResponse = client.search(s -> s.index("user_test").aggregations("maxAge", a ->a.max(m -> m.field("age")))
                , User.class);
        searchResponse.aggregations().entrySet().forEach(f -> System.out.println(f.getKey() + ":" + f.getValue().max().value()));

        transport.close();
        restClient.close();
    }

• 分組查詢

    @Test
    public void groupQueryDocument2() throws IOException {
        RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);

        // 分組查詢
        SearchResponse<User> searchResponse = client.search(s -> s.index("user_test")
                        .aggregations("ageGroup", a ->a.terms(t -> t.field("age")))
                , User.class);
        searchResponse.aggregations().get("ageGroup").lterms().buckets().array().forEach(f -> System.out.println(f.key() + ":" + f.docCount()));

        transport.close();
        restClient.close();
    }

分組查詢實(shí)質(zhì)上是聚合查詢的一種

看到這里的小伙伴點(diǎn)個(gè)免費(fèi)的贊吧，感謝支持?。。?/strong>文章來源地址http://www.zghlxwxcb.cn/news/detail-403398.html

到了這里，關(guān)于Elasticsearch8.x版本中RestHighLevelClient被棄用，新版本中全新的Java客戶端Elasticsearch Java API Client中常用API練習(xí)的文章就介紹完了。如果您還想了解更多內(nèi)容，請?jiān)谟疑辖撬阉鱐OY模板網(wǎng)以前的文章或繼續(xù)瀏覽下面的相關(guān)文章，希望大家以后多多支持TOY模板網(wǎng)！