前言

关于ES的介绍，这里我就不提了,相关的文章非常多。

  Java high-level REST client 是目前官方推荐使用的客户端，
  High Level REST Client 与 Elasticsearch 具有相同的发布周期。
  故我们能够使用最新版的 Elasticsearch。

Maven

<properties>
        ...
        <es.client.version>6.5.0</es.client.version>
</properties>

...

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>${es.client.version}</version>
    <exclusions>
        <exclusion>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
        </exclusion>
    </exclusions>
</dependency>

<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>${es.client.version}</version>
</dependency>

elasticsearch必须要单独依赖，否则会出现如下错误:

nested exception is java.lang.NoClassDefFoundError: org/elasticsearch/common/xcontent/DeprecationHandler

elasticsearch-rest-high-level-client 6.5集成的是
org.elasticsearch:elasticsearch:5.6.11
5.x版本，并未提供DeprecationHandler类，而是DeprecationRestHandler
如下图：

Dependencies

为了简化EsClient的创建流程和多es集群的支持，我写了一个构造器

public class EsClientBuilder {

    private int connectTimeoutMillis = 1000;
    private int socketTimeoutMillis = 30000;
    private int connectionRequestTimeoutMillis = 500;
    private int maxConnectPerRoute = 10;
    private int maxConnectTotal = 30;

    private final List<HttpHost> httpHosts;


    private EsClientBuilder(List<HttpHost> httpHosts) {
        this.httpHosts = httpHosts;
    }


    public EsClientBuilder setConnectTimeoutMillis(int connectTimeoutMillis) {
        this.connectTimeoutMillis = connectTimeoutMillis;
        return this;
    }

    public EsClientBuilder setSocketTimeoutMillis(int socketTimeoutMillis) {
        this.socketTimeoutMillis = socketTimeoutMillis;
        return this;
    }

    public EsClientBuilder setConnectionRequestTimeoutMillis(int connectionRequestTimeoutMillis) {
        this.connectionRequestTimeoutMillis = connectionRequestTimeoutMillis;
        return this;
    }

    public EsClientBuilder setMaxConnectPerRoute(int maxConnectPerRoute) {
        this.maxConnectPerRoute = maxConnectPerRoute;
        return this;
    }

    public EsClientBuilder setMaxConnectTotal(int maxConnectTotal) {
        this.maxConnectTotal = maxConnectTotal;
        return this;
    }


    public static EsClientBuilder build(List<HttpHost> httpHosts) {
        return new EsClientBuilder(httpHosts);
    }


    public RestHighLevelClient create() {

        HttpHost[] httpHostArr = httpHosts.toArray(new HttpHost[0]);
        RestClientBuilder builder = RestClient.builder(httpHostArr);

        builder.setRequestConfigCallback(requestConfigBuilder -> {
            requestConfigBuilder.setConnectTimeout(connectTimeoutMillis);
            requestConfigBuilder.setSocketTimeout(socketTimeoutMillis);
            requestConfigBuilder.setConnectionRequestTimeout(connectionRequestTimeoutMillis);
            return requestConfigBuilder;
        });

        builder.setHttpClientConfigCallback(httpClientBuilder -> {
            httpClientBuilder.setMaxConnTotal(maxConnectTotal);
            httpClientBuilder.setMaxConnPerRoute(maxConnectPerRoute);
            return httpClientBuilder;
        });


        return new RestHighLevelClient(builder);
    }


}

application.yml

elasticsearch:
  nodes: localhost:9200
  schema: http
  max-connect-total: 50
  max-connect-per-route: 10
  connection-request-timeout-millis: 500
  socket-timeout-millis: 30000
  connect-timeout-millis: 1000

然后是Configuration

@Configuration
public class ESConfig {

    @Value("${elasticsearch.nodes}")
    private List<String> nodes;

    @Value("${elasticsearch.schema}")
    private String schema;

    @Value("${elasticsearch.max-connect-total}")
    private Integer maxConnectTotal;

    @Value("${elasticsearch.max-connect-per-route}")
    private Integer maxConnectPerRoute;

    @Value("${elasticsearch.connection-request-timeout-millis}")
    private Integer connectionRequestTimeoutMillis;

    @Value("${elasticsearch.socket-timeout-millis}")
    private Integer socketTimeoutMillis;

    @Value("${elasticsearch.connect-timeout-millis}")
    private Integer connectTimeoutMillis;


    @Bean
    public RestHighLevelClient getRestHighLevelClient() {

        List<HttpHost> httpHosts = new ArrayList<>();

        for (String node : nodes) {
            try {
                String[] parts = StringUtils.split(node, ":");
                Assert.notNull(parts,"Must defined");
                Assert.state(parts.length == 2, "Must be defined as 'host:port'");
                httpHosts.add(new HttpHost(parts[0], Integer.parseInt(parts[1]), schema));
            } catch (RuntimeException ex) {
                throw new IllegalStateException(
                        "Invalid ES nodes " + "property '" + node + "'", ex);
            }
        }

        return EsClientBuilder.build(httpHosts)
                .setConnectionRequestTimeoutMillis(connectionRequestTimeoutMillis)
                .setConnectTimeoutMillis(connectTimeoutMillis)
                .setSocketTimeoutMillis(socketTimeoutMillis)
                .setMaxConnectTotal(maxConnectTotal)
                .setMaxConnectPerRoute(maxConnectPerRoute)
                .create();


    }
}

语法和transportclient基本很相似，这里做一下简单举例

BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();

boolQueryBuilder.must(QueryBuilders.termQuery("field","value"));
boolQueryBuilder.must(QueryBuilders.wildcardQuery("field","value"));
boolQueryBuilder.must(QueryBuilders.rangeQuery("field").gt("value"));
boolQueryBuilder.must(QueryBuilders.termsQuery("field","value"));

SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(boolQueryBuilder);
sourceBuilder.sort("field", SortOrder.ASC);

SearchRequest searchRequest = new SearchRequest();
searchRequest.types(esTable.getType());
searchRequest.searchType(SearchType.QUERY_THEN_FETCH);
searchRequest.source(sourceBuilder);
client.search(searchRequest)

如果是cluster，application.yml的nodes设置多个ip:host逗号隔开就可以了。
ps:多个集群，在application.yml 再定义一组配置，在ESConfig 中创建两个name 不同的RestHighLevelClient bean.(暂时还未尝试，需要用的同学可以试试)

作者：流风夜雪
邮箱：csycsy2510316@163.com
发布日期：2019-03-04
更新日期：2019-03-04
欢迎交流。