Java API 操作

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，废话不多说，直接开始。

1.1 引入依赖

		<dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.8.0</version>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.8.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.8.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.8.2</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.9</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

1.2 客户端对象

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

        // todo


        // 关闭客户端
        client.close();

1.3 索引操作

1.3.1 创建索引

// 创建索引
        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);

1.3.2 查看索引

// 查询索引-请求对象
        GetIndexRequest request = new GetIndexRequest("user");
        //发送请求
        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());

响应结果：

1.3.3 删除索引

// 删除索引 - 请求对象
        DeleteIndexRequest request = new DeleteIndexRequest("user");
        // 发送请求
        AcknowledgedResponse response = client.indices().delete(request, RequestOptions.DEFAULT);
        // 操作结果
        System.out.println("操作结果：" + response.isAcknowledged());

响应结果：

1.4 文档操作

1.4.1 新增文档

// 新增文档 - 请求对象
        IndexRequest request = new IndexRequest();
        // 设置索引及唯一性表示
        request.index("user").id("1001");

        User user = new User();
        user.setName("zhangsan");
        user.setAge(30);
        user.setSex("男");

        ObjectMapper objectMapper = new ObjectMapper();
        String productJson = objectMapper.writeValueAsString(user);

        // 提那家文档数据，数据格式为JSON格式
        request.source(productJson, XContentType.JSON);
        // 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());

响应结果：

1.4.2 修改文档

// 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());

响应结果：

1.4.3 查询文档

// 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());

响应结果：

1.4.4 删除文档

// 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());

响应结果：

1.4.5 批量新增

//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:" + responses.getItems());

响应结果：

1.4.6 批量删除

//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:" + responses.getItems());

响应结果：

1.5 高级查询

1.5.1 请求体查询

1.5.1.1 查询所有索引数据

// 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("<<========");

响应结果：

1.5.1.2 term 查询，查询条件为关键字

// 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.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("<<========");

响应结果：

1.5.1.3 分页查询

// 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.query(QueryBuilders.matchAllQuery());
        // 分页查询
        // 当前页其实索引(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("<<========");

响应结果：

1.5.1.4 数据排序

// 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.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("<<========");

响应结果：

1.5.1.5 过滤字段

// 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.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("<<========");

响应结果：

1.5.1.6 Bool 查询

// 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"));
        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("<<========");

响应结果：

1.5.1.7 范围查询

// 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");
        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========>>");

响应结果：

1.5.1.8 模糊查询

// 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.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("<<========");

响应结果：

1.5.1.9 高亮查询

// 高亮查询
        SearchRequest request = new SearchRequest().indices("student");
        //2.创建查询请求体构建器
        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();
        highlightBuilder.preTags("<font color='red'>");//设置标签前缀
        highlightBuilder.postTags("</font>");//设置标签后缀
        highlightBuilder.field("name");//设置高亮字段
        //设置高亮构建对象
        sourceBuilder.highlighter(highlightBuilder);
        //设置请求体
        request.source(sourceBuilder);
        //3.客户端发送请求，获取响应对象
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        //4.打印响应结果
        SearchHits hits = response.getHits();
        System.out.println("took::"+response.getTook());
        System.out.println("time_out::"+response.isTimedOut());
        System.out.println("total::"+hits.getTotalHits());
        System.out.println("max_score::"+hits.getMaxScore());
        System.out.println("hits::::>>");
        for (SearchHit hit : hits) {
            String sourceAsString = hit.getSourceAsString();
            System.out.println(sourceAsString);
            //打印高亮结果
            Map<String, HighlightField> highlightFields = hit.getHighlightFields();
            System.out.println(highlightFields);
        }
        System.out.println("<<::::");

响应结果：

1.5.1.10 聚合查询

1.最大年龄

SearchRequest request = new SearchRequest().indices("student");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.aggregation(AggregationBuilders.max("maxAge").field("age"));
        //设置请求体
        request.source(sourceBuilder);
        //3.客户端发送请求，获取响应对象
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        //4.打印响应结果
        SearchHits hits = response.getHits();
        System.out.println(response);

响应结果：

2.分组统计

 SearchRequest request = new SearchRequest().indices("student");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.aggregation(AggregationBuilders.terms("age_groupby").field("age"));
//设置请求体
                request.source(sourceBuilder);
//3.客户端发送请求，获取响应对象
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
//4.打印响应结果
        SearchHits hits = response.getHits();
        System.out.println(response);

响应结果：

到此，基础的语法与应用练习完。不对的地方欢迎批评指正。