SpringBoot 操作 ElasticSearch 详解

1.ElasticSearch简介

Elasticsearch是位于Elastic Stack核心的分布式搜索和分析引擎。Logstash和Beats有助于收集，聚合和丰富您的数据并将其存储在Elasticsearch中。使用Kibana，您可以交互式地探索，可视化和共享对数据的见解，并管理和监视堆栈。

2.Maven 引入相关依赖

pom.xml配置如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.james</groupId>
    <artifactId>elasticsearch_demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>elasticsearch_demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.4.0</version>
        </dependency>

        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.4.7</version>
        </dependency>

        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.4.0</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.12.2</version>
            <exclusions>
                <exclusion>
                    <groupId>com.fasterxml.jackson.core</groupId>
                    <artifactId>jackson-core</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>com.fasterxml.jackson.core</groupId>
                    <artifactId>jackson-annotations</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.12.2</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.12.2</version>
        </dependency>

        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.5</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

3.ElasticSearch 连接配置

(1) application.properties配置

elasticsearch.address=localhost:9200
elasticsearch.username=elastic
elasticsearch.password=elastic

(2) java 连接配置类

@Configuration
public class ElasticsearchConfig {

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

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

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

    @Bean(destroyMethod = "close")
    public RestHighLevelClient restClient() {
        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        credentialsProvider.setCredentials(AuthScope.ANY,
                new UsernamePasswordCredentials(userName, password));


        // 拆分地址
        List<HttpHost> hostLists = new ArrayList<>();
        String[] hostList = address.split(",");
        for (String addr : hostList) {
            String host = addr.split(":")[0];
            String port = addr.split(":")[1];
            hostLists.add(new HttpHost(host, Integer.parseInt(port), "http"));
        }
        // 转换成 HttpHost 数组
        HttpHost[] httpHost = hostLists.toArray(new HttpHost[]{});

        RestClientBuilder builder = RestClient.builder(httpHost).
                setHttpClientConfigCallback(httpClientBuilder ->
                        httpClientBuilder.setMaxConnTotal(100)
                                .setMaxConnPerRoute(100)
                                .setDefaultCredentialsProvider(credentialsProvider)).
                setRequestConfigCallback(requestConfigBuilder ->
                        requestConfigBuilder.setConnectTimeout(10000)
                                            .setSocketTimeout(60000));
        RestHighLevelClient client = new RestHighLevelClient(builder);
        return client;

    }
}

4. Java 代码示例

@Service
@Slf4j
public class ProfileService {


    private RestHighLevelClient restClient;
    private ObjectMapper objectMapper;

    @Autowired
    public ProfileService(RestHighLevelClient restClient, ObjectMapper objectMapper) {
        this.restClient = restClient;
        this.objectMapper = objectMapper;
    }

    public String createProfileDocument(ProfileDocument document) throws Exception {
        UUID uuid = UUID.randomUUID();
        document.setId(uuid.toString());
        IndexRequest indexRequest = new IndexRequest(INDEX, TYPE, document.getId())
                .source(convertProfileDocumentToMap(document));
        IndexResponse indexResponse = restClient.index(indexRequest, RequestOptions.DEFAULT);
        return indexResponse.getResult().name();
    }

    public List<ProfileDocument> findAll() throws Exception {
        SearchRequest searchRequest = buildSearchRequest(INDEX, TYPE);
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.query(QueryBuilders.matchAllQuery());
        searchRequest.source(searchSourceBuilder);
        SearchResponse searchResponse =
                restClient.search(searchRequest, RequestOptions.DEFAULT);
        return getSearchResult(searchResponse);
    }

    private SearchRequest buildSearchRequest(String index, String type) {
        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices(index);
        searchRequest.types(type);
        return searchRequest;
    }

    private List<ProfileDocument> getSearchResult(SearchResponse response) {
        SearchHit[] searchHit = response.getHits().getHits();
        List<ProfileDocument> profileDocuments = new ArrayList<>();
        for (SearchHit hit : searchHit) {
            profileDocuments
                    .add(objectMapper
                            .convertValue(hit
                                    .getSourceAsMap(), ProfileDocument.class));
        }
        return profileDocuments;
    }

    private Map<String, Object> convertProfileDocumentToMap(ProfileDocument profileDocument) {
        return objectMapper.convertValue(profileDocument, Map.class);
    }

    private ProfileDocument convertMapToProfileDocument(Map<String, Object> map) {
        return objectMapper.convertValue(map, ProfileDocument.class);
    }

}