Elasticsearch之Java Api操作

1、Elasticsearch概述

2、Elasticsearch入门

3、Elasticsearch之Java Api操作

4、Elasticsearch集群搭建

5、Elasticsearch进阶

6、Elasticsearch集成SpringBoot

7、Elasticsearch优化

8、Elasticsearch系列总结

一、创建Maven项目 

Elasticsearch软件是由 Java 语言开发的，所以也可以通过 Java API 的方式对 Elasticsearch服务进行访问。

修改pom 文件，增加 Maven 依赖关系。

        
            org.projectlombok
            lombok
            1.16.12
        

        
            org.springframework.boot
            spring-boot-starter
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        

        
            org.elasticsearch
            elasticsearch
            7.8.0
        
        
        
            org.elasticsearch.client
            elasticsearch-rest-high-level-client
            7.8.0
        
        
        
            org.apache.logging.log4j
            log4j-api
            2.8.2
        
        
            org.apache.logging.log4j
            log4j-core
            2.8.2
        
        
            com.fasterxml.jackson.core
            jackson-databind
            2.9.9
        
        
        
            junit
            junit
            4.12
        
    

 1.1 客户端对象

创建类，代码中创建 Elasticsearch 客户端对象

因为早期版本的客户端对象已经不再推荐使用，且在未来版本中会被删除，所以这里我们采用高级 REST 客户端对象

    public static void main(String[] args) throws IOException {
        // 创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("127.0.0.1", 9200, "http"))
        );

        // 关闭客户端连接
        client.close();
    }

注意：

9200 端口为 Elasticsearch 的 Web 通信端口 localhost 为启动 ES 服务的主机名

执行代码，查看控制台信息：

 二、索引操作

ES服务器正常启动后，可以通过 Java API 客户端对象对 ES 索引进行操作 

public class EsIndex {

    public static void main(String[] args) throws IOException {

        // 创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("127.0.0.1", 9200, "http"))
        );

        // 关闭客户端连接
        client.close();
    }

    // 创建索引
    public static void createIndex(RestHighLevelClient client) throws IOException {
        // 创建索引 - 请求对象
        CreateIndexRequest request = new CreateIndexRequest("user");
        // 发送请求，获取响应
        CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT);
        boolean acknowledged = response.isAcknowledged();
        // 响应状态
        System.out.println("操作状态 = " + acknowledged);
    }

    // 查看索引
    public static void getIndex(RestHighLevelClient client) throws IOException {
        // 查询索引 - 请求对象
        GetIndexRequest request = new GetIndexRequest("user");
        // 发送请求，获取响应
        GetIndexResponse response = client.indices().get(request, RequestOptions.DEFAULT);
        System.out.println("aliases: " + response.getAliases());
        System.out.println("mappings: " + response.getMappings());
        System.out.println("settings: " + response.getSettings());
    }

    // 删除索引
    public static void deleteIndex(RestHighLevelClient client) throws IOException {
        // 删除索引 - 请求对象
        DeleteIndexRequest request = new DeleteIndexRequest("user");
        // 发送请求，获取响应
        AcknowledgedResponse response = client.indices().delete(request, RequestOptions.DEFAULT);
        // 操作结果
        System.out.println("操作结果: " + response.isAcknowledged());
    }
}

三、文档操作

public class EsDoc {

    public static void main(String[] args) throws IOException {
        // 创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("127.0.0.1", 9200, "http"))
        );

        // 关闭客户端连接
        client.close();
    }

    // 创建文档
    public static void createDoc(RestHighLevelClient client) throws IOException {
        // 新增文档 - 请求对象
        IndexRequest request = new IndexRequest();
        // 设置索引及唯一性标识
        request.index("user").id("1001");
        // 创建数据对象
        User user = new User();
        user.setAge(26);
        user.setSex("男");
        user.setName("jak");
        ObjectMapper objectMapper = new ObjectMapper();
        String productJson = objectMapper.writeValueAsString(user);
        // 添加文档数据, 数据格式为Json格式
        request.source(productJson, XContentType.JSON);
        // 客户端发送请求，获取响应对象
        IndexResponse response = client.index(request, RequestOptions.DEFAULT);
        // 打印结果信息
        System.out.println("_index: " + response.getIndex());
        System.out.println("id: " + response.getId());
        System.out.println("_result: " + response.getResult());
    }

    // 修改文档
    public static void updateDoc(RestHighLevelClient client) throws IOException {
        // 修改文档 - 请求对象
        UpdateRequest request = new UpdateRequest();
        // 配置修改参数
        request.index("user").id("1001");
        // 设置请求体，对数据进行修改
        request.doc(XContentType.JSON, "sex", "女");
        // 客户端发送请求，获取响应对象
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        System.out.println("_index: " + response.getIndex());
        System.out.println("_id: " + response.getId());
        System.out.println("_result: " + response.getResult());
    }

    // 查询文档
    public static void getDoc(RestHighLevelClient client) throws IOException {
        // 创建请求对象
        GetRequest request = new GetRequest().index("user").id("1001");
        // 客户端发送请求，获取响应对象
        GetResponse response = client.get(request, RequestOptions.DEFAULT);
        // 打印结果信息
        System.out.println("_index: " + response.getIndex());
        System.out.println("_type: " + response.getType());
        System.out.println("_id: " + response.getId());
        System.out.println("source: " + response.getSourceAsString());
    }

    // 删除文档
    public static void deleteDoc(RestHighLevelClient client) throws IOException {
        // 创建请求对象
        DeleteRequest request = new DeleteRequest().index("user").id("1");
        // 客户端发送请求，获取响应对象
        DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);
        // 打印信息
        System.out.println(response.toString());
    }

    // 批量新增
    public static void bulkCreateDoc(RestHighLevelClient client) throws IOException {
        // 创建批量新增请求对象
        BulkRequest request = new BulkRequest();
        request.add(new IndexRequest().index("user").id("1001").source(XContentType.JSON, "name", "zhangsan"));
        request.add(new IndexRequest().index("user").id("1002").source(XContentType.JSON, "name", "lisi"));
        request.add(new IndexRequest().index("user").id("1003").source(XContentType.JSON, "name", "wangwu"));
        // 客户端发送请求，获取响应对象
        BulkResponse responses = client.bulk(request, RequestOptions.DEFAULT);
        // 打印结果信息
        System.out.println("took: " + responses.getTook());
        System.out.println("items: " + Arrays.toString(responses.getItems()));
    }

    // 批量删除
    public static void bulkDeleteDoc(RestHighLevelClient client) throws IOException {
        // 创建批量删除请求对象
        BulkRequest request = new BulkRequest();
        request.add(new DeleteRequest().index("user").id("1001"));
        request.add(new DeleteRequest().index("user").id("1002"));
        request.add(new DeleteRequest().index("user").id("1003"));
        // 客户端发送请求，获取响应对象
        BulkResponse responses = client.bulk(request, RequestOptions.DEFAULT);
        // 打印结果信息
        System.out.println("took: " + responses.getTook());
        System.out.println("items: " + Arrays.toString(responses.getItems()));

    }
}

四、高级查询

public class EsSearch {

    public static void main(String[] args) throws IOException {

        // 创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("127.0.0.1", 9200, "http"))
        );

        // 关闭客户端连接
        client.close();
    }

    // 查询所有索引数据
    public static void matchAllQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        // 查询所有数据
        sourceBuilder.query(QueryBuilders.matchAllQuery());
        request.source(sourceBuilder);

        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");

    }

    // term查询，查询条件为关键字
    public static void termQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        // 查询所有数据
        sourceBuilder.query(QueryBuilders.termQuery("age", "30"));
        request.source(sourceBuilder);

        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }

    // 分页查询
    public static void pageQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        // 查询所有数据
        sourceBuilder.query(QueryBuilders.matchAllQuery());

        // 分页查询
        // 当前页起始索引(第一条数据的顺序号)，from
        sourceBuilder.from(0);
        // 每页显示多少条size
        sourceBuilder.size(2);

        request.source(sourceBuilder);
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }

    // 数据排序
    public static void sortOrderQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        // 查询所有数据
        sourceBuilder.query(QueryBuilders.matchAllQuery());

        // 排序
        sourceBuilder.sort("age", SortOrder.ASC);

        request.source(sourceBuilder);
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }

    // 过滤字段
    public static void filterFieldsQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        // 查询所有数据
        sourceBuilder.query(QueryBuilders.matchAllQuery());

        // 查询字段过滤
        String[] excludes = {};
        String[] includes = {"name", "age"};
        sourceBuilder.fetchSource(includes, excludes);

        request.source(sourceBuilder);
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }

    // Bool查询
    public static void boolQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

        BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
        // 必须包含
        boolQueryBuilder.must(QueryBuilders.matchQuery("age", "30"));
        // 一定不含
        boolQueryBuilder.mustNot(QueryBuilders.matchQuery("name", "zhangsan"));
        // 可能包含
        boolQueryBuilder.should(QueryBuilders.matchQuery("sex", "男"));

        // 查询所有数据
        sourceBuilder.query(boolQueryBuilder);
        request.source(sourceBuilder);
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }

    // 范围查询
    public static void rangeQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

        RangeQueryBuilder rangeQuery = QueryBuilders.rangeQuery("age");
        // 大于等于
        rangeQuery.gte("30");
        // 小于等于
        rangeQuery.lte("40");


        // 查询所有数据
        sourceBuilder.query(rangeQuery);
        request.source(sourceBuilder);
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }

    // 范围查询
    public static void fuzzyQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

        // 查询所有数据
        sourceBuilder.query(QueryBuilders.fuzzyQuery("name", "zhangsan").fuzziness(Fuzziness.ONE));
        request.source(sourceBuilder);
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }

    // 高亮查询
    public static void highLightQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

        // 构建查询方式: 高亮查询
        TermsQueryBuilder termsQueryBuilder = QueryBuilders.termsQuery("name", "zhangsan");
        // 设置查询方式
        sourceBuilder.query(termsQueryBuilder);

        // 构建高亮字段
        HighlightBuilder highlightBuilder = new HighlightBuilder();
        // 设置标签前缀
        highlightBuilder.preTags("");
        // 设置标签后缀
        highlightBuilder.postTags("");
        // 设置高亮字段
        highlightBuilder.field("name");
        // 设置高亮构建对象
        sourceBuilder.highlighter(highlightBuilder);
        // 设置请求体
        request.source(sourceBuilder);

        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }

    // 聚合查询
    public static void AggrQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.aggregation(AggregationBuilders.max("maxAge").field("age"));
        // 设置请求体
        request.source(sourceBuilder);
        // 客户端发送请求，获取响应对象
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }

    // 分组统计
    public static void groupQuery(RestHighLevelClient client) throws IOException {
        // 创建搜索请求对象
        SearchRequest request = new SearchRequest();
        request.indices("student");

        // 构建查询的请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.aggregation(AggregationBuilders.terms("age_group_by").field("age"));
        // 设置请求体
        request.source(sourceBuilder);
        // 客户端发送请求，获取响应对象
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        // 查询匹配
        SearchHits hits = response.getHits();
        System.out.println("took: " + response.getTook());
        System.out.println("timeout: " + response.isTimedOut());
        System.out.println("total: " + hits.getTotalHits());
        System.out.println("MaxScore: " + hits.getMaxScore());
        System.out.println("hits------------->");
        for (SearchHit hit : hits) {
            // 输出每条查询的结果信息
            System.out.println(hit.getSourceAsString());
        }
        System.out.println("<-----------------");
    }
}

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