2.ElasticSearch-Java API

一、基础使用

1.1 Maven 坐标

    <dependencies>
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.8.0</version>
        </dependency>
        <!--es的客户端-->
        <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>2.13.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.13.3</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.14.1</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

1.2 创建客户端对象

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

1.3 索引

1.3.1 创建索引

        //创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
        //创建索引
        CreateIndexRequest request = new CreateIndexRequest("user2");
        CreateIndexResponse createIndexResponse = client.indices().create(request, RequestOptions.DEFAULT);//第二个是默认的一个请求配置
        boolean acknowledged = createIndexResponse.isAcknowledged();
        if (acknowledged) {
            System.out.println("响应成功");
        }
        //关闭连接
        client.close();

1.3.2 查询索引

        //创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
 
        GetIndexRequest request = new GetIndexRequest("user");
        GetIndexResponse getIndexResponse = client.indices().get(request, RequestOptions.DEFAULT);
        System.out.println(getIndexResponse.getAliases() );
        System.out.println(getIndexResponse.getMappings());
        System.out.println(getIndexResponse.getSettings());
        //关闭连接
        client.close();

结果如下所示：

1.3.3 删除索引

        //创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
        DeleteIndexRequest request = new DeleteIndexRequest("user");
        AcknowledgedResponse response = client.indices().delete(request, RequestOptions.DEFAULT);
        System.out.println(response.isAcknowledged());
        //关闭连接
        client.close();

1.4 文档

1.4.1 新增

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

        //索引
        IndexRequest request = new IndexRequest();
        request.index("user").id("1001");

        User user = new User();
        user.setName("zhangsan");
        user.setAge("30");
        user.setSex("男");
        //向ES插入数据，必须将数据转换成JSON
        ObjectMapper mapper = new ObjectMapper();
        request.source(mapper.writeValueAsString(user), XContentType.JSON);
        //插入数据
        IndexResponse response = client.index(request, RequestOptions.DEFAULT);
        System.out.println( response.getResult());// 返回值为 CREATED/UPDATED
        //关闭连接
        client.close();

1.4.2 修改

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

        //索引
        UpdateRequest request = new UpdateRequest();
        request.index("user").id("1001");

        request.doc(XContentType.JSON, "sex","女");//局部修改
        //插入数据
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        System.out.println(response.getResult());// 返回值为 CREATED/UPDATED
        //关闭连接
        client.close();

1.4.3 查询

        //创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
        GetRequest request = new GetRequest();
        request.index("user").id("1001");
        GetResponse response = client.get(request, RequestOptions.DEFAULT);
        System.out.println(response.getIndex());
        System.out.println(response.getSourceAsString());
        //关闭连接
        client.close();

1.4.4 删除

        //创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
        DeleteRequest request = new DeleteRequest();
        request.index("user").id("1001");
        DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);
        System.out.println(response.toString());

        //关闭连接
        client.close();

1.4.5 批量新增

        //创建客户端对象
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(new HttpHost("localhost", 9200, "http")));
        //批量添加数据
        BulkRequest request = new BulkRequest();
        request.add(new IndexRequest().index("user").id("1001").source(XContentType.JSON, "name", "张三"));
        request.add(new IndexRequest().index("user").id("1002").source(XContentType.JSON, "name", "李四"));
        request.add(new IndexRequest().index("user").id("1003").source(XContentType.JSON, "name", "王五"));

        BulkResponse response = client.bulk(request, RequestOptions.DEFAULT);
        System.out.println(response.getTook());//花费了多长时间
        System.out.println(Arrays.toString(response.getItems()));//多个响应

        //关闭连接
        client.close();

1.4.6 批量删除

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

        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"));

        BulkResponse response = client.bulk(request, RequestOptions.DEFAULT);
        System.out.println(response.getTook());//花费了多长时间
        System.out.println(Arrays.toString(response.getItems()));//多个响应

        //关闭连接
        client.close();

1.4.7 高级查询

1.4.7.1 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("<<========");

1.4.7.2 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("<<========");

1.4.7.3 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("<<========");

1.4.7.4 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("<<========");

1.4.7.5 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("<<========");

1.4.7.6 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("<<========");

1.4.7.6 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("<<========");

1.4.7.7 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("<<========");

1.4.7.8 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("<<::::");

1.4.7.9 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);