简介
在项目开发过程中需要从Elasticsearch中查询日志数据，下面介绍从Elasticsearch中查询索引全部数据，以及按照时间区间查询索引数据。

引入依赖

<!-- Elasticsearch客户端 -->
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>7.9.1</version>
</dependency>

<!-- Elasticsearch版本 -->
<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>7.9.1</version>
</dependency>

创建配置类

import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class ElasticsearchConfig {
    public static final RequestOptions COMMON_OPTIONS;

    static {
        RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
        COMMON_OPTIONS = builder.build();
    }

    @Bean
    public RestHighLevelClient esRestClient() {
        RestClientBuilder builder = null;
        builder = RestClient.builder(new HttpHost("ip address", 9200, "http"));
        RestHighLevelClient client = new RestHighLevelClient(builder);
        return client;
    }
}

查询索引下的全部数据

public static void matchAllQuery() throws Exception {
    ElasticsearchConfig elasticSearchConfig = new ElasticsearchConfig();
    RestHighLevelClient client = elasticSearchConfig.esRestClient();

    // 搜索请求对象
    SearchRequest searchRequest = new SearchRequest("shenyu-access-logging");
    // 指定类型
    searchRequest.types("_doc");
    // 搜索源构建对象
    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    // 搜索方式
    // matchAllQuery搜索全部，设置查询数据条数为20。
    searchSourceBuilder.query(QueryBuilders.matchAllQuery());
    searchSourceBuilder.size(20);
    // 设置源字段过虑，第一个参数结果集包括哪些字段，第二个参数表示结果集不包括哪些字段
    searchSourceBuilder.fetchSource(new String[] {"requestUri", "requestHeader", "requestBody", "responseHeader", "responseBody"}, new String[]{});
    // 向搜索请求对象中设置搜索源
    searchRequest.source(searchSourceBuilder);
    // 执行搜索，向ES发起http请求
    SearchResponse searchResponse = client.search(searchRequest, ElasticsearchConfig.COMMON_OPTIONS);
    // 搜索结果
    SearchHits hits = searchResponse.getHits();
    // 匹配到的总记录数
    TotalHits totalHits = hits.getTotalHits();
    // 得到匹配度高的文档
    SearchHit[] searchHits = hits.getHits();

    for (SearchHit hit: searchHits) {
        // 文档的主键
        String id = hit.getId();
        // 源文档内容
        Map<String, Object> sourceAsMap = hit.getSourceAsMap();
        System.out.println(sourceAsMap);
    }
}

按照时间区间查询索引数据

public static void matchTimeRangeQuery() throws Exception {
    ElasticsearchConfig elasticSearchConfig = new ElasticsearchConfig();
    RestHighLevelClient client = elasticSearchConfig.esRestClient();

    // 搜索请求对象
    SearchRequest searchRequest = new SearchRequest("shenyu-access-logging");
    // 指定类型
    searchRequest.types("_doc");
    // 搜索源构建对象
    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    // 搜索方式
    // 按时间区间查询，设置查询数据条数为20。
    searchSourceBuilder.query(QueryBuilders.rangeQuery("timeLocal.keyword").from("2022-11-02 15:21:22.794").to("2022-11-02 16:22:33.794"));
    searchSourceBuilder.size(20);
    // 设置源字段过虑，第一个参数结果集包括哪些字段，第二个参数表示结果集不包括哪些字段
    searchSourceBuilder.fetchSource(new String[] {"timeLocal", "requestUri", "requestHeader", "requestBody", "responseHeader", "responseBody"}, new String[]{});
    // 向搜索请求对象中设置搜索源
    searchRequest.source(searchSourceBuilder);
    // 执行搜索，向ES发起http请求
    SearchResponse searchResponse = client.search(searchRequest, ElasticsearchConfig.COMMON_OPTIONS);
    // 搜索结果
    SearchHits hits = searchResponse.getHits();
    // 匹配到的总记录数
    TotalHits totalHits = hits.getTotalHits();
    // 得到匹配度高的文档
    SearchHit[] searchHits = hits.getHits();

    for (SearchHit hit: searchHits) {
        // 文档的主键
        String id = hit.getId();
        // 源文档内容
        Map<String, Object> sourceAsMap = hit.getSourceAsMap();
        System.out.println(sourceAsMap);
    }
}