ElasticSearch基础 java操作es归纳

java操作es有2种方式：

1.通过9300端口 tcp ransport-api.jar 但不能适配版本 不建议使用

2.通过9200端口 http Elasticsearch-Rest-Client 官方restclient 建议使用

导入依赖

//导入依赖
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>7.4.2</version>
</dependency>
//导入的版本与es版本一致7.4.2
//打开maven插件看dependencies中管理的依赖es版本是7.9.3
//因为springboot已经对es的版本做了管理 xml重写下es版本

    <properties>
        <java.version>1.8</java.version>
        <elasticsearch.version>7.4.2</elasticsearch.version>
    </properties>

springboot中es版本也改过来了

配置es

//类似数据库dao配置 代码通用的

@Configuration
public class GuliESConfig {

    public static final RequestOptions COMMON_OPTIONS;

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

    @Bean
    public RestHighLevelClient esRestClient() {
        RestClientBuilder builder = null;
        // 可以指定多个es
        builder = RestClient.builder(new HttpHost("192.168.112.151", 9200, "http")
//                ,new HttpHost("host", 9200, "http")
        );
        RestHighLevelClient client = new RestHighLevelClient(builder);
        return client;
    }

}

//其它代码用到es注入就行了
    @Autowired
    private RestHighLevelClient esRestClient;

java es保存测试 IndexRequest

   @Autowired
    private RestHighLevelClient esRestClient; 
  /**
     *  保存数据
     * @throws IOException
     */
    @Test
    void indexData() throws IOException{
        //设置保存的索引和id
        IndexRequest indexRequest = new IndexRequest("users");
        indexRequest.id("1");

        //保存的数据 这里指定json类型
        indexRequest.source("{\"test\":1}", XContentType.JSON);

        //执行保存 index同步 indexAsync异步
        IndexResponse index = esRestClient.index(indexRequest, GuliESConfig.COMMON_OPTIONS);
        System.out.println(index);
    }

java es 检索测试 SearchRequest

相当查询 "query": { "match": { "address": "Mill" } }

    @Test
    public void find() throws IOException {
        // 1 创建检索请求
        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("bank");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        // 构造检索条件
//        sourceBuilder.query();
//        sourceBuilder.from();
//        sourceBuilder.size();
//        sourceBuilder.aggregation();
        sourceBuilder.query(QueryBuilders.matchQuery("address","mill"));
        System.out.println(sourceBuilder.toString());

        searchRequest.source(sourceBuilder);

        // 2 执行检索
        SearchResponse response = esRestClient.search(searchRequest, GuliESConfig.COMMON_OPTIONS);
        // 3 分析响应结果
        System.out.println(response.toString());
    }

查询结果转为bean

        // 3.1 获取java bean   Account是bean类
        SearchHits hits = response.getHits();
        SearchHit[] hits1 = hits.getHits();
        for (SearchHit hit : hits1) {
            hit.getId();
            hit.getIndex();
            String sourceAsString = hit.getSourceAsString();
            Account account = JSON.parseObject(sourceAsString, Account.class);
            System.out.println(account);
        }

聚合检索测试

搜索address中包含mill的所有人的年龄分布以及平均年龄，平均薪资

GET bank/_search
{
  "query": {
    "match": {
      "address": "Mill"
    }
  },
  "aggs": {
    "ageAgg": {
      "terms": {
        "field": "age",
        "size": 10
      }
    },
    "ageAvg": {
      "avg": {
        "field": "age"
      }
    },
    "balanceAvg": {
      "avg": {
        "field": "balance"
      }
    }
  }
}

java代码测试如下

    /**
     * 聚合检索
     * @throws IOException
     */
    @Test
    public void jhfind() throws IOException {
        // 1 创建检索请求
        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("bank");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        // 构造检索条件
//        sourceBuilder.query();
//        sourceBuilder.from();
//        sourceBuilder.size();
//        sourceBuilder.aggregation();
        sourceBuilder.query(QueryBuilders.matchQuery("address","mill"));
        //AggregationBuilders工具类构建AggregationBuilder
        // 构建第一个聚合条件:按照年龄的值分布
        TermsAggregationBuilder agg1 = AggregationBuilders.terms("agg1").field("age").size(10);// 聚合名称
// 参数为AggregationBuilder
        sourceBuilder.aggregation(agg1);
        // 构建第二个聚合条件:平均薪资
        AvgAggregationBuilder agg2 = AggregationBuilders.avg("agg2").field("balance");
        sourceBuilder.aggregation(agg2);

        System.out.println("检索条件"+sourceBuilder.toString());

        searchRequest.source(sourceBuilder);

        // 2 执行检索
        SearchResponse response = esRestClient.search(searchRequest, GuliESConfig.COMMON_OPTIONS);
        // 3 分析响应结果
        System.out.println(response.toString());
    }

检索结果处理

// 3.2 获取检索到的分析信息
//实际测试检索结果aggregations下名称不是"agg2"而是"avg#agg2"  不是"agg1"而是"lterms#agg1" 暂不知道是什么原因 先记录着
Aggregations aggregations = response.getAggregations();
Terms agg21 = aggregations.get("agg2"); //"avg#agg2"  
for (Terms.Bucket bucket : agg21.getBuckets()) {
    String keyAsString = bucket.getKeyAsString();
    System.out.println(keyAsString);
}