Java API for Elasticsearch: Configuration, CRUD, DSL Queries, Pagination, Sorting, and Highlighting

This guide shows how to set up a Spring Boot project to work with Elasticsearch 6.2.1 using the elasticsearch‑rest‑high‑level‑client and the low‑level RestClient.

Dependencies

<!-- ES client -->
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>${elasticsearch.version}</version>
</dependency>
<!-- ES version -->
<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>${elasticsearch.version}</version>
</dependency>

Bean configuration

@Configuration
public class ESConfig {
    @Value("${yunshangxue.elasticsearch.hostlist}")
    private String hostlist; // e.g. 127.0.0.1:9200

    @Bean
    public RestHighLevelClient restHighLevelClient() {
        String[] split = hostlist.split(",");
        HttpHost[] httpHostArray = new HttpHost[split.length];
        for (int i = 0; i < split.length; i++) {
            String item = split[i];
            httpHostArray[i] = new HttpHost(item.split(":")[0], Integer.parseInt(item.split(":")[1]), "http");
        }
        return new RestHighLevelClient(RestClient.builder(httpHostArray));
    }

    @Bean
    public RestClient restClient() {
        String[] split = hostlist.split(",");
        HttpHost[] httpHostArray = new HttpHost[split.length];
        for (int i = 0; i < split.length; i++) {
            String item = split[i];
            httpHostArray[i] = new HttpHost(item.split(":")[0], Integer.parseInt(item.split(":")[1]), "http");
        }
        return RestClient.builder(httpHostArray).build();
    }
}

YAML configuration

yunshangxue:
  elasticsearch:
    hostlist: ${eshostlist:127.0.0.1:9200}

Index operations (CRUD)

@Test
public void testDelIndex() throws IOException {
    IndicesClient indices = client.indices();
    DeleteIndexRequest deleteIndexRequest = new DeleteIndexRequest("ysx_course");
    DeleteIndexResponse response = indices.delete(deleteIndexRequest);
    System.out.println(response.isAcknowledged());
}

public void testAddIndex() throws IOException {
    IndicesClient indices = client.indices();
    CreateIndexRequest request = new CreateIndexRequest("ysx_course");
    request.settings(Settings.builder()
        .put("number_of_shards", "1")
        .put("number_of_replicas", "0"));
    request.mapping("doc", "{
" +
        \"properties\": {
" +
        \"description\": {
    \"type\": \"text\",
    \"analyzer\": \"ik_max_word\",
    \"search_analyzer\": \"ik_smart\"
},
    \"name\": {
    \"type\": \"text\",
    \"analyzer\": \"ik_max_word\",
    \"search_analyzer\": \"ik_smart\"
},
    \"pic\": {
    \"type\": \"text\",
    \"index\": false
},
    \"price\": {
    \"type\": \"scaled_float\",
    \"scaling_factor\": 100
},
    \"studymodel\": {
    \"type\": \"keyword\"
},
    \"timestamp\": {
    \"type\": \"date\",
    \"format\": \"yyyy-MM-dd HH:mm:ss||yyyy-MM-dd||epoch_millis\"
}
}
", XContentType.JSON);
    CreateIndexResponse response = indices.create(request);
    System.out.println(response.isAcknowledged());
}

DSL search examples

Match all query with source filtering

{
  "query": { "match_all": {} },
  "_source": ["name", "studymodel"]
}

Term query (exact match)

{
  "query": { "term": { "name": "spring" } },
  "_source": ["name", "studymodel"]
}

Match query with

minimum_should_match

{
  "query": {
    "match": {
      "description": { "query": "spring开发", "operator": "or" }
    }
  }
}

Multi‑match query across name and description with boosting

{
  "query": {
    "multi_match": {
      "query": "Spring开发框架",
      "minimum_should_match": "70%",
      "fields": ["name^10", "description"]
    }
  }
}

Boolean query with filters

{
  "query": {
    "bool": {
      "must": [
        { "multi_match": { "query": "spring框架", "minimum_should_match": "50%", "fields": ["name^10", "description"] } },
        { "term": { "studymodel": "201001" } }
      ],
      "filter": [
        { "term": { "studymodel": "201001" } },
        { "range": { "price": { "gte": 60, "lte": 100 } } }
      ]
    }
  }
}

Sorting

searchSourceBuilder.sort("studymodel", SortOrder.DESC);
searchSourceBuilder.sort("price", SortOrder.ASC);

Highlighting results

HighlightBuilder hb = new HighlightBuilder();
 hb.preTags("<em>");
 hb.postTags("</em>");
 hb.field(new HighlightBuilder.Field("name"));
 hb.field(new HighlightBuilder.Field("description"));
searchSourceBuilder.highlighter(hb);

All code snippets are kept intact inside

tags, and the article also notes common pitfalls such as missing <code>yunshangxue.elasticsearch.hostlist

placeholders and Maven project misconfiguration.