Elastic Search 的底層是開源庫 Lucene。但是Lucene的使用門檻比較高，必須自己寫程式碼去呼叫它的介面。而Elastic Search的出現正是為了解決了這個問題，它是 Lucene 的封裝，提供了 REST API 的操作介面，我們可以開箱即用。

環境

• JDK版本：8
• SpringBoot:2.x
• ES版本：7.1.1

依賴

		<!--   整合es client，並排除低版本依賴(5.6)     -->
		<dependency>
			<groupId>org.elasticsearch.client</groupId>
			<artifactId>elasticsearch-rest-high-level-client</artifactId>
			<version>7.1.1</version>
			<exclusions>
				<exclusion>
					<groupId>org.elasticsearch</groupId>
					<artifactId>elasticsearch</artifactId>
				</exclusion>
				<exclusion>
					<groupId>org.elasticsearch.client</groupId>
					<artifactId>elasticsearch-rest-client</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
		<dependency>
			<groupId>org.elasticsearch.client</groupId>
			<artifactId>elasticsearch-rest-client</artifactId>
			<version>7.1.1</version>
		</dependency>
		<dependency>
			<groupId>org.elasticsearch</groupId>
			<artifactId>elasticsearch</artifactId>
			<version>7.1.1</version>
		</dependency>
 

配置

使用配置類配置，可以參考如下所示：
先建立一個builder，用於初始化ES client

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);
    }
}
 

再交給spring容器管理：

@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();
    }
}
 

再配置一下常用的配置：

#配置es
elasticsearch:
  #  如果是cluster，application.yml的nodes設定多個ip:host逗號隔開即可。
  nodes: 127.0.0.1:9200
  schema: http
  max-connect-total: 50
  max-connect-per-route: 10
  connection-request-timeout-millis: 500
  socket-timeout-millis: 30000
  connect-timeout-millis: 1000

使用

接下來我們測試一下配置是否生效，一個簡單的驗證送給大家，如下所示：

@Autowired
    private RestHighLevelClient client;
    @Test
    public void test() throws IOException {
        MainResponse info = client.info(RequestOptions.DEFAULT);
        System.out.println(info.toString());
    }

配置生效的話，就會返回Elastic Search的配置資訊：包含當前節點、叢集、版本等資訊。
SpringBoot整合ES至此結束。

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