Java API文档的使用详解

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文章目录

学会使用 API 文档是一个开发者基本的素养，而许多初学者并不会在意 API 文档的使用，甚至从来没有接触过，所以写下这篇文章探讨 API 文档的使用，希望能够帮助到你，先赞后看，养成习惯！

1. 概念

API，Application Programming Interface， 应用程序编程接口。通俗的说，就是已经定义好的类，我们可以直接使用的。例如我们经常使用的 String 类。

Java 中提供了丰富的基础类，并为这些基础类提供了 API 文档，用于告诉开发者如何使用这些类以及这些类里包含的方法。

在开发者学习过程中，我们不可能去详细的学习每一个类，此时，我们就可以去使用 API 文档查询需要使用的类，包括查看其构造方法，成员变量，成员方法等，JDK API 文档就像是 Java 类的字典，帮助开发者快速使用 Java 定义的一些基础类。

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Elasticsearch——使用Java API实现ES中的索引映射文档操作

文章目录：

1.开篇

2.案例详解

2.1 创建ES客户端：完成与ES服务端的连接

2.2 创建索引

2.3 查看索引

2.4 删除索引

2.5 创建文档

2.6 修改文档

2.7 查看文档

2.8 删除文档

2.9 批量创建文档

2.10 批量删除文档

2.11 全量查询

2.12 条件查询

2.13 分页查询

2.14 排序查询

2.15 过滤字段查询

2.16 组合条件查询

2.17 范围查询

2.18 模糊查询

2.19 聚合查询

2.20 分组查询

1.开篇

在上一篇文章中，对ES中的创建/查看/删除索引、创建定义映射、创建/查看/修改/删除文档的这些操作有了一定的了解认识，但是是通过Postman + JSON串的方法来实现的。文章链接：https://blog.csdn.net/weixin_43823808/article/details/119911746

那么，这篇文章，仍然是对ES中的索引、映射、文档进行操作，只是方法换成了Java API。

2.案例详解

首先需要创建一个maven工程，必然要添加ES相关的依赖。

同时双击ES安装目录的bin目录下的 elasticsearch.bat ，先启动ES服务端。

        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.8.0</version>
        </dependency>
        <!-- elasticsearch 的客户端 -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.8.0</version>
        </dependency>
        <!-- elasticsearch 依赖 2.x 的 log4j -->
        <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>
        <!-- junit 单元测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

2.1 创建ES客户端：完成与ES服务端的连接

后面的一二十个案例都是依照这个模板代码来的。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;

import java.io.IOException;

/**
 *
 */
public class ESTestClient {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //关闭ES客户端
        esClient.close();
    }
}

2.2 创建索引

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.CreateIndexRequest;
import org.elasticsearch.client.indices.CreateIndexResponse;

import java.io.IOException;

/**
 *
 */
public class ESTestIndexCreate {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //创建索引 --- 请求对象
        CreateIndexRequest request = new CreateIndexRequest("user");
        //发送请求 --- 获取响应
        CreateIndexResponse response = esClient.indices().create(request, RequestOptions.DEFAULT);

        //响应状态
        boolean acknowledged = response.isAcknowledged();
        System.out.println("索引操作：" + acknowledged);

        //关闭ES客户端
        esClient.close();
    }
}

2.3 查看索引

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.GetIndexRequest;
import org.elasticsearch.client.indices.GetIndexResponse;

import java.io.IOException;

/**
 *
 */
public class ESTestIndexSearch {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //查询索引 --- 请求对象
        GetIndexRequest request = new GetIndexRequest("user");
        //发送请求 --- 获取响应
        GetIndexResponse response = esClient.indices().get(request, RequestOptions.DEFAULT);

        //响应状态
        System.out.println(response.getAliases());
        System.out.println(response.getMappings());
        System.out.println(response.getSettings());

        //关闭ES客户端
        esClient.close();
    }
}

2.4 删除索引

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
import org.elasticsearch.action.support.master.AcknowledgedResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;

import java.io.IOException;

/**
 *
 */
public class ESTestIndexDelete {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //删除索引 --- 请求对象
        DeleteIndexRequest request = new DeleteIndexRequest("user");
        //发送请求 --- 获取响应
        AcknowledgedResponse response = esClient.indices().delete(request,RequestOptions.DEFAULT);

        //响应状态
        System.out.println(response.isAcknowledged());

        //关闭ES客户端
        esClient.close();
    }
}

2.5 创建文档

索引有了，就相当于有了数据库。接下来就需要向数据库中建表、添加数据。建表自然要有表结构（有哪些属性、这些属性分别都是什么数据类型），也就是ES中的映射，在Java代码中就可以采用实体类来实现。

package com.szh.es;

/**
 *
 */
public class User {

    private String name;
    private String sex;
    private Integer age;

    //getter and setter
}

package com.szh.es;

import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.http.HttpHost;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;

import java.io.IOException;

/**
 *
 */
public class ESTestDocInsert {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //创建文档 --- 请求对象
        IndexRequest request = new IndexRequest();
        //设置索引及索引中文档的唯一性标识id（如果不指定，则ES会默认随机生成一个id）
        request.index("user").id("1001");

        //创建数据对象（文档内容）
        User user = new User();
        user.setName("张起灵");
        user.setSex("man");
        user.setAge(21);

        //向ES中插入数据，必须将数据格式转换为JSON
        ObjectMapper objectMapper = new ObjectMapper();
        String userJson = objectMapper.writeValueAsString(user);
        request.source(userJson, XContentType.JSON);

        //发送请求 --- 获取响应
        IndexResponse response = esClient.index(request, RequestOptions.DEFAULT);
        System.out.println(response.getResult());

        //关闭ES客户端
        esClient.close();
    }
}

2.6 修改文档

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.update.UpdateRequest;
import org.elasticsearch.action.update.UpdateResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;

import java.io.IOException;

/**
 *
 */
public class ESTestDocUpdate {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //修改文档 --- 请求对象
        UpdateRequest request = new UpdateRequest();
        //配置修改参数 --- 表示要修改user索引中id为1001的文档内容
        request.index("user").id("1001");
        //将修改后的内容，以JSON格式写入请求体中
        request.doc(XContentType.JSON,"age",18);

        //发送请求 --- 获取响应
        UpdateResponse response = esClient.update(request,RequestOptions.DEFAULT);
        System.out.println(response.getResult());

        //关闭ES客户端
        esClient.close();
    }
}

2.7 查看文档

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.get.GetRequest;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;

import java.io.IOException;

/**
 *
 */
public class ESTestDocSearch {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //查询文档 --- 请求对象
        GetRequest request = new GetRequest();
        //设置请求参数 --- 表示要查询user索引中id为1001的文档内容
        request.index("user").id("1001");

        //发送请求 --- 获取响应
        GetResponse response = esClient.get(request,RequestOptions.DEFAULT);
        System.out.println(response.getSourceAsString());

        //关闭ES客户端
        esClient.close();
    }
}

2.8 删除文档

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.delete.DeleteRequest;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;

import java.io.IOException;

/**
 *
 */
public class ESTestDocDelete {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //删除文档 --- 请求对象
        DeleteRequest request = new DeleteRequest();
        //设置请求参数 --- 表示要删除user索引中id为1001的文档
        request.index("user").id("1001");
        
        //发送请求 --- 获取响应
        DeleteResponse response = esClient.delete(request,RequestOptions.DEFAULT);
        System.out.println(response.getResult());

        //关闭ES客户端
        esClient.close();
    }
}

2.9 批量创建文档

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;

import java.io.IOException;

/**
 *
 */
public class ESTestDocInsertBatch {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //批量新增文档 --- 请求对象
        BulkRequest request = new BulkRequest();
        //以JSON格式批量新增文档 --- 存入请求体中
        request.add(new IndexRequest().index("user").id("1001").source(XContentType.JSON, "name", "张起灵","sex","boy","age",21));
        request.add(new IndexRequest().index("user").id("1002").source(XContentType.JSON, "name", "小哥","sex","boy","age",18));
        request.add(new IndexRequest().index("user").id("1003").source(XContentType.JSON, "name", "小宋","sex","boy","age",20));

        //发送请求 --- 获取响应
        BulkResponse response = esClient.bulk(request, RequestOptions.DEFAULT);
        System.out.println(response.getTook());

        //关闭ES客户端
        esClient.close();
    }
}

2.10 批量删除文档

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.delete.DeleteRequest;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;

import java.io.IOException;

/**
 *
 */
public class ESTestDocDeleteBatch {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //批量删除文档 --- 请求对象
        BulkRequest request = new BulkRequest();
        //将要删除的文档id存入请求体中
        request.add(new DeleteRequest().index("user").id("1001"));
        request.add(new DeleteRequest().index("user").id("1002"));
        request.add(new DeleteRequest().index("user").id("1003"));

        //发送请求 --- 获取响应
        BulkResponse response = esClient.bulk(request,RequestOptions.DEFAULT);
        System.out.println(response.getTook());
        System.out.println(response.getItems());

        //关闭ES客户端
        esClient.close();
    }
}

2.11 全量查询

因为上面两个代码案例分别进行了批量创建、批量删除。所以这里首先执行一次批量创建的代码，确保索引中有多条数据供我们查询。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;

import java.io.IOException;

/**
 *
 */
public class ESTestDocInsertBatch {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //批量新增文档 --- 请求对象
        BulkRequest request = new BulkRequest();
        //以JSON格式批量新增文档 --- 存入请求体中
        request.add(new IndexRequest().index("user").id("1001").source(XContentType.JSON, "name", "张起灵","sex","boy","age",21));
        request.add(new IndexRequest().index("user").id("1002").source(XContentType.JSON, "name", "小哥","sex","boy","age",18));
        request.add(new IndexRequest().index("user").id("1003").source(XContentType.JSON, "name", "小宋","sex","boy","age",20));
        request.add(new IndexRequest().index("user").id("1004").source(XContentType.JSON, "name", "冷少","sex","boy","age",25));
        request.add(new IndexRequest().index("user").id("1005").source(XContentType.JSON, "name", "Java软件工程师","sex","girl","age",40));

        //发送请求 --- 获取响应
        BulkResponse response = esClient.bulk(request, RequestOptions.DEFAULT);
        System.out.println(response.getTook());

        //关闭ES客户端
        esClient.close();
    }
}

下面首先进行全量查询操作。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //1.查询索引中的全部文档 --- matchAllQuery 全量查询
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体 --- 存入搜索请求对象中
        request.source(new SearchSourceBuilder().query(QueryBuilders.matchAllQuery()));

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

2.12 条件查询

做匹配查询，查询年龄age=21的文档内容。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //2.条件查询--- termQuery age=21
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体 --- 存入搜索请求对象中
        request.source(new SearchSourceBuilder().query(QueryBuilders.termQuery("age",21)));

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

2.13 分页查询

做全量查询，对查询结果进行分页显示，每页2条数据，查询第1页。

查看第几页：（页码 - 1）*每页条数

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //3.分页查询
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体
        SearchSourceBuilder builder = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery());
        builder.from(0);
        builder.size(2);
        //将构建好的查询请求体存入搜索请求对象中
        request.source(builder);

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

2.14 排序查询

做全量查询，对查询结果中的年龄age字段做降序排序。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //4.对查询结果进行排序
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体
        SearchSourceBuilder builder = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery());
        builder.sort("age", SortOrder.DESC);
        //将构建好的查询请求体存入搜索请求对象中
        request.source(builder);

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

2.15 过滤字段查询

做全量查询，同时排除性别sex字段。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //5.过滤字段
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体
        SearchSourceBuilder builder = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery());
        String[] excludes = {"sex"};
        String[] includes = {};
        builder.fetchSource(includes,excludes);
        //将构建好的查询请求体存入搜索请求对象中
        request.source(builder);

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

2.16 组合条件查询

查询年龄 age=18 或者 name=张起灵 的文档内容。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //6.组合查询
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体
        SearchSourceBuilder builder = new SearchSourceBuilder();
        BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
        boolQueryBuilder.should(QueryBuilders.matchQuery("age",18));
        boolQueryBuilder.should(QueryBuilders.matchQuery("name","张起灵"));
        builder.query(boolQueryBuilder);
        //将构建好的查询请求体存入搜索请求对象中
        request.source(builder);

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

2.17 范围查询

查询年龄age字段大于等于18、小于25的文档内容。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //7.范围查询
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体
        SearchSourceBuilder builder = new SearchSourceBuilder();
        RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("age");
        rangeQueryBuilder.gte(18);
        rangeQueryBuilder.lt(25);
        builder.query(rangeQueryBuilder);
        //将构建好的查询请求体存入搜索请求对象中
        request.source(builder);

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

2.18 模糊查询

builder.query(QueryBuilders.fuzzyQuery("name","小张").fuzziness(Fuzziness.ONE)); 最后的这个枚举类型 ONE，表示查询结果中允许与我定义的name字段为 小张 相差1个字符，也就是说，查询出的结果要么包含 小、要么包含 张、或者就是小张。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //8.模糊查询
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体
        SearchSourceBuilder builder = new SearchSourceBuilder();
        //FuzzyQueryBuilder fuzzyQueryBuilder = QueryBuilders.fuzzyQuery("name","小张");
        //fuzzyQueryBuilder.fuzziness(Fuzziness.ONE);
        //builder.query(fuzzyQueryBuilder);
        //上面三行代码 等价于 下面这行代码
        builder.query(QueryBuilders.fuzzyQuery("name","小张").fuzziness(Fuzziness.ONE));
        //将构建好的查询请求体存入搜索请求对象中
        request.source(builder);

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

2.19 聚合查询

查询age字段，年龄最大的文档内容。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //9.聚合查询
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体
        SearchSourceBuilder builder = new SearchSourceBuilder();
        AggregationBuilder aggregationBuilder = AggregationBuilders.max("maxAge").field("age");
        builder.aggregation(aggregationBuilder);
        //将构建好的查询请求体存入搜索请求对象中
        request.source(builder);

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

2.20 分组查询

根据age年龄字段进行group分组查询。

package com.szh.es;

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.RangeQueryBuilder;
import org.elasticsearch.index.query.TermsQueryBuilder;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;

/**
 *
 */
public class ESTestDocQuery {
    public static void main(String[] args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //10.分组查询
        //创建搜索请求对象
        SearchRequest request = new SearchRequest();
        //设置参数 --- 表示查询哪个索引中的文档内容
        request.indices("user");
        //构建查询的请求体
        SearchSourceBuilder builder = new SearchSourceBuilder();
        AggregationBuilder aggregationBuilder = AggregationBuilders.terms("ageGroup").field("age");
        builder.aggregation(aggregationBuilder);
        //将构建好的查询请求体存入搜索请求对象中
        request.source(builder);

        //发送请求 --- 获取响应
        SearchResponse response = esClient.search(request,RequestOptions.DEFAULT);
        //获取查询到的结果集
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits()); //结果集的条数
        System.out.println(response.getTook());  //总耗时
        //遍历结果集
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }

        //关闭ES客户端
        esClient.close();
    }
}

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