ES-4- Java API 操作

绝地灬酷狼 2022-09-11 08:28 207阅读 0赞

**创建**  **Maven**  **项目**

<dependencies>
     <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>
    </dependencies>

**客户端对象**

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

// 创建客户端对象
    RestHighLevelClient client = new RestHighLevelClient(
    RestClient.builder(new HttpHost("localhost", 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：

**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

**1)**  **创建索引**

// 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**

// 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**

// 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());

**文档操作**

**1)**  **新增文档**

创建数据模型

class User { 
     private String name; 
     private Integer age; 
     private String sex;
     ......
    }

创建数据，添加到文档中

// 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.setName("zhangsan");
    user.setAge(30);
    user.setSex("男");
    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);
    3.打印结果信息
    System.out.println("_index:" + response.getIndex());
    System.out.println("_id:" + response.getId());
    System.out.println("_result:" + response.getResult());

**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());

**3)**  **查询文档**

//1.创建请求对象
    GetRequest request = new GetRequest().index("user").id("1001");
    //2.客户端发送请求，获取响应对象
    GetResponse response = client.get(request, RequestOptions.DEFAULT);
    3.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());

**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());

**5)**  **批量操作**

//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());

  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());

**高级查询**

**1)**  **请求体查询**

// 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();
    // 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

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

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

数据排序

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

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

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

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========>>");
    for (SearchHit hit : hits) {
    //输出每条查询的结果信息
    System.out.println(hit.getSourceAsString());
    }
    System.out.println("<<========");

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(Fu
    zziness.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**

// 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("<<::::");

**聚合查询**

最大年龄

// 高亮查询
    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);

分组统计

// 高亮查询
    SearchRequest request = new SearchRequest().indices("student");
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
    sourceBuilder.aggregation(AggregationBuilders.terms("age_groupby").field("ag
    e"));
    //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);