ElasticSearch学习笔记

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.3.4.RELEASE
         
    
    com.bingmous
    esRestClient
    0.0.1-SNAPSHOT
    esRestClient
    Demo project for Spring Boot
    
        11
        
        7.8.0
    
    
        
            org.springframework.boot
            spring-boot-starter-web
        
        
        
            org.elasticsearch.client
            elasticsearch-rest-high-level-client
            7.8.0
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
            
                
                    org.junit.vintage
                    junit-vintage-engine
                
            
        
    

    
    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

@Configuration
public class ElasticSearchConfig {
    
    public static final RequestOptions COMMON_OPTIONS;
    static {
        RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
//        builder.addHeader("Authorization", "Bearer " + TOKEN);
//        builder.setHttpAsyncResponseConsumerFactory(
//                new HttpAsyncResponseConsumerFactory
//                        .HeapBufferedResponseConsumerFactory(30 * 1024 * 1024 * 1024));
        COMMON_OPTIONS = builder.build();
    }

    
    @Bean
    public RestHighLevelClient esRestClient() {
        //1 先获取到一个RestClientBuilder
        RestClientBuilder builder = RestClient.builder(new HttpHost("localhost",9200,"http"));
        //2 再用RestClientBuilder构建一个client
        RestHighLevelClient client = new RestHighLevelClient(builder);
        return client;
    }
}

@SpringBootApplication
public class MainApplication {
    public static void main(String[] args) throws IOException {
        ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args);
//        RestHighLevelClient esClient = run.getBean("esClient", RestHighLevelClient.class);
//        System.out.println(esClient);
    }
}

测试类

用Spring的驱动跑单元测试，junit4
//@RunWith(SpringRunner.class)
@SpringBootTest
public class EsRestClientApplicationTests {

    @Autowired
    private RestHighLevelClient esRestClient; //自动注入esRestClient

    //测试是否注入成功
    @Test
    public void contextLoads() {
        System.out.println(esRestClient);
    }

    //索引数据：保存、更新数据
    @Test
    public void indexData() throws IOException {
        IndexRequest indexRequest = new IndexRequest("users"); //1 索引
        indexRequest.id("1"); //2 数据的id
        // 第一种方式Map
//        indexRequest.source("userName","zhangsan","age",18);
        // 第二种方式json
        User user = new User("zhangsan","18");
        String jsonString = JSON.toJSonString(user);
        indexRequest.source(jsonString, XContentType.JSON); //3 要保存的内容

        //4 请求的响应
        IndexResponse index = esRestClient.index(indexRequest, ElasticSearchConfig.COMMON_OPTIONS);
        System.out.println(index);
    }

    //检索数据
    @Test
    public void searchData() throws IOException {
        //1 创建检索请求
        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("bank"); // 指定索引

        //2 指定DSL，检索条件
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); // 构建查询语句的，有所有根 *** 作
//        searchSourceBuilder.query(); //所有根 *** 作都在这里构建
//        searchSourceBuilder.from();
//        searchSourceBuilder.size();
//        searchSourceBuilder.sort();
        //2.1 query里面的match
        searchSourceBuilder.query(QueryBuilders.matchQuery("address","mill"));
        //2.2 query里面的聚合，按照年龄的值分布进行聚合
        TermsAggregationBuilder termsAggregationBuilder = AggregationBuilders.terms("ageAgg").field("age").size(10); //terms聚合
        searchSourceBuilder.aggregation(termsAggregationBuilder);
        //2.3 query里面的聚合，计算平均薪资
        AvgAggregationBuilder avgAggregationBuilder = AggregationBuilders.avg("balanceAvg").field("balance");
        searchSourceBuilder.aggregation(avgAggregationBuilder);

        searchRequest.source(searchSourceBuilder); //将检索条件放入searchRequest中

        //3 执行检索
        SearchResponse searchResponse = esRestClient.search(searchRequest, ElasticSearchConfig.COMMON_OPTIONS);

        //4 分析结果 searchResponse
//        System.out.println(searchResponse);
//        Map map = JSON.parseObject(searchResponse.toString(), Map.class);//将结果封装成Map
        //4.1 直接获取查到的数据
        SearchHits hits = searchResponse.getHits(); // 最外面的hits
        SearchHit[] searchHits = hits.getHits(); //实际的数据hits，里面的_source是原数据，通常封装成bean
        for (SearchHit hit : searchHits) {
//            hits" : [
//            {
//                "_index" : "bank",
//                    "_type" : "_doc",
//                    "_id" : "970",
//                    "_score" : 5.4032025,
//                    "_source" : {
//            hit.getIndex();hit.getType();hit.getScore(); //所有的字段都有对应的方法
            String string = hit.getSourceAsString(); //将数据作为字符串返回，生成对应的bean对象
//            System.out.println(string); //通过在线格式化工具自动生成实体类
            Account account = JSON.parseObject(string, Account.class); //转为对应的实体类
            System.out.println(account);
        }
        //4.2 获取这次检索的分析信息
        Aggregations aggregations = searchResponse.getAggregations(); //分析结果在聚合中
        //按年龄聚合结果
        Terms ageAgg = aggregations.get("ageAgg"); //根据检索时定义的聚合名字获取到聚合结果
        for (Terms.Bucket bucket : ageAgg.getBuckets()) { //分析结果数据在每个聚合的buckets里面
            String key = bucket.getKeyAsString();
            long docCount = bucket.getDocCount();
            System.out.println("key: " + key + ", doc_count: " + docCount);
        }
        //平均薪资聚合
        Avg balanceAvg = aggregations.get("balanceAvg"); //拿到聚合的平均值
        System.out.println("balanceAvg: " + balanceAvg.getValueAsString());
    }
}

测试代码对应的kibana测试