【ElasticSearch】ES案例：旅游酒店搜索

「爱情、让人受尽委屈。」 2023-10-13 13:32 85阅读 0赞

#### 文章目录 ####

*  一、项目分析
 *  二、需求1：酒店搜索功能
 *  三、需求2：添加过滤功能
 *  四、需求3：我附近的酒店
 *  五、需求4：置顶花广告费的酒店

## 一、项目分析 ##

启动hotel-demo项目，访问localhost:servicePort，即可访问static下的index.html：

![在这里插入图片描述][9e4bcc77f5324e8181406ceca80d07cb.png]

从页面分析，我们需要实现搜索、分页、排序等功能。点击页面，可以看到list接口的传参为：

![在这里插入图片描述][789fdbc23f734c32bfcfcfd527016d6c.png]

## 二、需求1：酒店搜索功能 ##

接下来实现酒店搜索功能，完成关键字搜索和分页。

*  定义接参的Dto类

@Data
    public class RequestParam {
        
    
        private String key;
    
        private Integer page;  //pageNum
    
        private Integer size;  //pageSize
    
        private String sortBy;
    }

*  定义返回的结果类

@AllArgsConstructor
    @NoArgsConstructor
    @Data
    public class PageResult {
        
    
        private Long total;
    
        private List<HotelDoc>  hotelDocList;
    }

*  定义controller接口，接收页面请求

@RestController
    @RequestMapping("/hotel")
    public class HotelSearchController {
        
    
        @Resource
        IHotelService hotelService;
    
        @PostMapping("/list")
        public PageResult searchHotel(@RequestBody RequestParam requestParam){
        
            return hotelService.search(requestParam);
        }
    
    }

*  Service层要用到JavaRestHighLevelClient对象，在启动类中定义这个Bean

@SpringBootApplication
    public class HotelDemoApplication {
        
    
        public static void main(String[] args) {
        
            SpringApplication.run(HotelDemoApplication.class, args);
        }
    
        @Bean
        public RestHighLevelClient client(){
        
            return new RestHighLevelClient(RestClient.builder(
                    HttpHost.create("http://10.4.130.220:9200")
            ));
        }
    
    }

*  完成Service层，利用match查询实现根据关键字搜索酒店信息

public interface IHotelService extends IService<Hotel> {
        
        PageResult search(RequestParam requestParam);
    }

@Service
    public class HotelService extends ServiceImpl<HotelMapper, Hotel> implements IHotelService {
        
    
        @Resource
        RestHighLevelClient client;  //注入客户端操作的bean
    
        @Override
        public PageResult search(RequestParam requestParam) {
        
            try {
        
                SearchRequest request = new SearchRequest("hotel");
                //搜索关键字
                String key = requestParam.getKey();
                if (StringUtils.isNotEmpty(key)) {
           //有key就走全文检索
                    request.source().query(QueryBuilders.matchQuery("all", key));
                } else {
           //没key就走查所有
                    request.source().query(QueryBuilders.matchAllQuery());
                }
                //分页
                request.source().from((requestParam.getPage() - 1) * requestParam.getSize())    //(pageNum-1)*pageSize
                        .size(requestParam.getSize());
                        //发送请求
                SearchResponse response = client.search(request, RequestOptions.DEFAULT);
                //处理响应结果
                return handleResponse(response);
            } catch (IOException e) {
        
                throw new RuntimeException();
            }
    
        }
    	
    	//处理响应结果的方法
        private PageResult handleResponse(SearchResponse response) {
        
            SearchHits searchHits = response.getHits();
            long total = searchHits.getTotalHits().value;
            SearchHit[] hits = searchHits.getHits();
            //Stream流将hits中的每条数据都转为HotelDoc对象
            List<HotelDoc> hotelDocList = Arrays.stream(hits).map(t -> {
        
                String json = t.getSourceAsString();
                HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
                return hotelDoc;
            }).collect(Collectors.toList());
            return new PageResult(total, hotelDocList);
        }
    }

重启服务，搜索和分页已实现。

![在这里插入图片描述][42dfbb02d90c495595479a813b72a294.png]

## 三、需求2：添加过滤功能 ##

接下来添加品牌、城市、星级、价格的过滤功能。这里参与搜索的条件对应着不同的搜索类型，有全文检索，有精确查找，自然要用复合查询Boolean Search

![在这里插入图片描述][6f0b0d96da144e65b4dd9cd59c22391b.png]

*  修改接参dto类：

@Data
    public class RequestParam {
        
    
        private String key;
    
        private Integer page;  //pageNum
    
        private Integer size;  //pageSize
    
        private String sortBy;
    
    	private String brand;  
    	  
    	private String starName; 
    	   
    	private String city;    
    	
    	private Integer minPrice;    
    	
    	private Integer maxPrice;
    
    }

*  修改Service层实现，这里把搜索条件的构建单独抽取成方法，一来方便后面复用，二来让代码看着清爽点

@Service
    public class HotelService extends ServiceImpl<HotelMapper, Hotel> implements IHotelService {
        
    
        @Resource
        RestHighLevelClient client;
    
        @Override
        public PageResult search(RequestParam requestParam) {
        
            try {
        
                //准备request
                SearchRequest request = new SearchRequest("hotel");
                //构建查询条件
                buildBasicQuery(requestParam, request);
                //分页
                request.source().from((requestParam.getPage() - 1) * requestParam.getSize())
                        .size(requestParam.getSize());
                //发送请求
                SearchResponse response = client.search(request, RequestOptions.DEFAULT);
                //处理响应结果
                return handleResponse(response);
            } catch (IOException e) {
        
                throw new RuntimeException();
            }
    
        }
    
        private void buildBasicQuery(RequestParam requestParam, SearchRequest request) {
        
            BoolQueryBuilder booleanQuery = QueryBuilders.boolQuery();
            //关键字
            String key = requestParam.getKey();
            if (! isEmpty(key)) {
        
                booleanQuery.must(QueryBuilders.matchQuery("all", key));
            } else {
        
                booleanQuery.must(QueryBuilders.matchAllQuery());
            }
            //城市
            if (! isEmpty(requestParam.getCity())) {
        
                booleanQuery.filter(QueryBuilders.termQuery("city", requestParam.getCity()));
            }
            //品牌
            if (! isEmpty(requestParam.getBrand())) {
        
                booleanQuery.filter(QueryBuilders.termQuery("brand", requestParam.getBrand()));
            }
            //星级
            if (! isEmpty(requestParam.getStarName())) {
        
                booleanQuery.filter(QueryBuilders.termQuery("startName", requestParam.getStarName()));
            }
            //价格
            if (requestParam.getMaxPrice() != null && requestParam.getMinPrice() != null) {
        
                booleanQuery.filter(QueryBuilders.rangeQuery("price")
                        .lte(requestParam.getMaxPrice())
                        .gte(requestParam.getMinPrice()));
            }
            request.source().query(booleanQuery);
    
    
        }
    
        private static boolean isEmpty(String str){
        
            return str == null || "".equals(str);
        }
    }

![在这里插入图片描述][b184dbea52914b85a2ade0f91a5cc663.png]

## 四、需求3：我附近的酒店 ##

前端页面点击定位后，会将你所在的位置发送到后台：  
![在这里插入图片描述][4c4d7b89d0604062ac60ae23c9b254ed.png]  
接下来实现根据这个坐标，将酒店结果按照到这个点的距离升序排序。  
![在这里插入图片描述][0b787404c7f74b36bdf99bbe34354c00.png]

**距离排序与普通字段排序有所差异，对比如下：**

![在这里插入图片描述][44b190619c594303bb8a41b3a1d70ef5.png]

开始实现需求：

*  修改RequestParams参数，接收location字段

*  修改Service中，在分页前加排序逻辑

@Override
    public PageResult search(RequestParam requestParam) {
        
        try {
        
            //准备request
            SearchRequest request = new SearchRequest("hotel");
            //构建查询条件
            buildBasicQuery(requestParam, request);
            //排序
            String myLocation = requestParam.getLocation();
            if(! isEmpty(myLocation)){
        
                request.source().sort(SortBuilders
                        .geoDistanceSort("location",new GeoPoint(myLocation))
                        .order(SortOrder.ASC)
                        .unit(DistanceUnit.KILOMETERS));
            }
            //分页
            request.source().from((requestParam.getPage() - 1) * requestParam.getSize())
                    .size(requestParam.getSize());
            //发送请求
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);
            //处理响应结果
            return handleResponse(response);
        } catch (IOException e) {
        
            throw new RuntimeException();
        }
    
    }

但此时发现返回结果中少了距离你xxx千米的信息：

![在这里插入图片描述][3cb85212f97d46dda7e0ee3f4eeb4e57.png]

查看DSL返回结果，看到距离是在sort字段中：

![在这里插入图片描述][57bdb3e3fa80451880ea94b6bcffb9b9.png]

因此需要修改结果处理的方法，且最后pageResult中是HotelDoc对象的集合，因此，修改Hoteldoc类，加distance距离字段：

@Data
    @NoArgsConstructor
    public class HotelDoc {
        
        private Long id;
        private String name;
        private String address;
        private Integer price;
        private Integer score;
        private String brand;
        private String city;
        private String starName;
        private String business;
        private String location;
        private String pic;
        //距离
        private Object distance;   //新加字段
    
        public HotelDoc(Hotel hotel) {
        
            this.id = hotel.getId();
            this.name = hotel.getName();
            this.address = hotel.getAddress();
            this.price = hotel.getPrice();
            this.score = hotel.getScore();
            this.brand = hotel.getBrand();
            this.city = hotel.getCity();
            this.starName = hotel.getStarName();
            this.business = hotel.getBusiness();
            this.location = hotel.getLatitude() + ", " + hotel.getLongitude();
            this.pic = hotel.getPic();
        }
    }

private PageResult handleResponse(SearchResponse response) {
        
        SearchHits searchHits = response.getHits();
        long total = searchHits.getTotalHits().value;
        SearchHit[] hits = searchHits.getHits();
        List<HotelDoc> hotelDocList = Arrays.stream(hits).map(t -> {
        
            String json = t.getSourceAsString();
            HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
            //开始加入距离
            Object[] sortValues = t.getSortValues();   //排序字段可能不止一个
            if(sortValues.length > 0 ){
        
                Object sortValue = sortValues[0];
                hotelDoc.setDistance(sortValue); 拿到sort值赋值给距离
            }
            return hotelDoc;
        }).collect(Collectors.toList());
        return new PageResult(total, hotelDocList);
    }

到此，需求实现：

![在这里插入图片描述][5fd10831cf524eb88f532894fc79689a.png]

## 五、需求4：置顶花广告费的酒店 ##

实现让指定的酒店在搜索结果中排名置顶：

![在这里插入图片描述][085107a77fe647a39d270b4d5e420008.png]  
**实现思路为：**

*  HotelDoc类添加标记字段isAD，Boolean类型
 *  对于出广告费的酒店，isAD为true，前端可用这个字段给酒店打广告标签
 *  使用function score给花钱的酒店人为增加权重，干涉排序

代码实现：

*  hotelDoc类：

*  更新ES数据，模拟某酒店出广告费

![在这里插入图片描述][cc4e1a0673dd4b0f9d7326739bf599e1.png]

*  加入function score算分认为控制，给isAD为true的加权

private void buildBasicQuery(RequestParam requestParam, SearchRequest request) {
        
        //BoolQuery原始查询条件，原始算分
        BoolQueryBuilder booleanQuery = QueryBuilders.boolQuery();
        //关键字
        String key = requestParam.getKey();
        if (!isEmpty(key)) {
        
            booleanQuery.must(QueryBuilders.matchQuery("all", key));
        } else {
        
            booleanQuery.must(QueryBuilders.matchAllQuery());
        }
        //城市
        if (!isEmpty(requestParam.getCity())) {
        
            booleanQuery.filter(QueryBuilders.termQuery("city", requestParam.getCity()));
        }
        //品牌
        if (!isEmpty(requestParam.getBrand())) {
        
            booleanQuery.filter(QueryBuilders.termQuery("brand", requestParam.getBrand()));
        }
        //星级
        if (!isEmpty(requestParam.getStarName())) {
        
            booleanQuery.filter(QueryBuilders.termQuery("startName", requestParam.getStarName()));
        }
        //价格
        if (requestParam.getMaxPrice() != null && requestParam.getMinPrice() != null) {
        
            booleanQuery.filter(QueryBuilders.rangeQuery("price")
                    .lte(requestParam.getMaxPrice())
                    .gte(requestParam.getMinPrice()));
        }
        
        //function score算分控制
        FunctionScoreQueryBuilder functionScoreQuery = QueryBuilders.functionScoreQuery(
                booleanQuery,  //第一个参数传入booleanQuery为原始查询，对应原始的相关性算分
                new FunctionScoreQueryBuilder.FilterFunctionBuilder[]{
          //第二个形参，function score数组，里面有个function score元素
                        new FunctionScoreQueryBuilder.FilterFunctionBuilder(  //function score元素对象，第一个参数传入筛选字段
                                QueryBuilders.termQuery("isAD", true),   //不再用酒店品牌筛选，而是isAD字段
                                ScoreFunctionBuilders.weightFactorFunction(10)  //算分函数，用默认的乘法，权重为10
                        )
                });
        request.source().query(functionScoreQuery);
    
    
    }

实现效果;

![在这里插入图片描述][5a067197e43e471abcaa41683a367e91.png]

Function Score查询可以控制文档的相关性算分，使用方式如下：

![在这里插入图片描述][22bfcb553b294c74a1146ad5d466a6c7.png]

最后贴上以上四个需求Service层代码：

import cn.itcast.hotel.domain.dto.RequestParam;
    import cn.itcast.hotel.domain.pojo.HotelDoc;
    import cn.itcast.hotel.domain.vo.PageResult;
    import cn.itcast.hotel.mapper.HotelMapper;
    import cn.itcast.hotel.domain.pojo.Hotel;
    import cn.itcast.hotel.service.IHotelService;
    import com.alibaba.fastjson.JSON;
    import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
    
    
    import org.elasticsearch.action.search.SearchRequest;
    import org.elasticsearch.action.search.SearchResponse;
    import org.elasticsearch.client.RequestOptions;
    import org.elasticsearch.client.RestHighLevelClient;
    import org.elasticsearch.common.geo.GeoPoint;
    import org.elasticsearch.common.unit.DistanceUnit;
    import org.elasticsearch.index.query.BoolQueryBuilder;
    import org.elasticsearch.index.query.QueryBuilders;
    import org.elasticsearch.index.query.functionscore.FunctionScoreQueryBuilder;
    import org.elasticsearch.index.query.functionscore.ScoreFunctionBuilders;
    import org.elasticsearch.search.SearchHit;
    import org.elasticsearch.search.SearchHits;
    import org.elasticsearch.search.sort.SortBuilders;
    import org.elasticsearch.search.sort.SortOrder;
    import org.springframework.stereotype.Service;
    
    import javax.annotation.Resource;
    import java.io.IOException;
    import java.util.Arrays;
    import java.util.List;
    import java.util.stream.Collectors;
    
    @Service
    public class HotelService extends ServiceImpl<HotelMapper, Hotel> implements IHotelService {
        
    
        @Resource
        RestHighLevelClient client;
    
        @Override
        public PageResult search(RequestParam requestParam) {
        
            try {
        
                //准备request
                SearchRequest request = new SearchRequest("hotel");
                //构建查询条件
                buildBasicQuery(requestParam, request);
                //排序
                String myLocation = requestParam.getLocation();
                if (!isEmpty(myLocation)) {
        
                    request.source().sort(SortBuilders
                            .geoDistanceSort("location", new GeoPoint(myLocation))
                            .order(SortOrder.ASC)
                            .unit(DistanceUnit.KILOMETERS));
                }
                //分页
                request.source().from((requestParam.getPage() - 1) * requestParam.getSize())
                        .size(requestParam.getSize());
                //发送请求
                SearchResponse response = client.search(request, RequestOptions.DEFAULT);
                //处理响应结果
                return handleResponse(response);
            } catch (IOException e) {
        
                throw new RuntimeException();
            }
    
        }
    
        private void buildBasicQuery(RequestParam requestParam, SearchRequest request) {
        
            //BoolQuery原始查询条件，原始算分
            BoolQueryBuilder booleanQuery = QueryBuilders.boolQuery();
            //关键字
            String key = requestParam.getKey();
            if (!isEmpty(key)) {
        
                booleanQuery.must(QueryBuilders.matchQuery("all", key));
            } else {
        
                booleanQuery.must(QueryBuilders.matchAllQuery());
            }
            //城市
            if (!isEmpty(requestParam.getCity())) {
        
                booleanQuery.filter(QueryBuilders.termQuery("city", requestParam.getCity()));
            }
            //品牌
            if (!isEmpty(requestParam.getBrand())) {
        
                booleanQuery.filter(QueryBuilders.termQuery("brand", requestParam.getBrand()));
            }
            //星级
            if (!isEmpty(requestParam.getStarName())) {
        
                booleanQuery.filter(QueryBuilders.termQuery("startName", requestParam.getStarName()));
            }
            //价格
            if (requestParam.getMaxPrice() != null && requestParam.getMinPrice() != null) {
        
                booleanQuery.filter(QueryBuilders.rangeQuery("price")
                        .lte(requestParam.getMaxPrice())
                        .gte(requestParam.getMinPrice()));
            }
    
            //function score算分控制
            FunctionScoreQueryBuilder functionScoreQuery = QueryBuilders.functionScoreQuery(
                    booleanQuery,  //第一个参数传入booleanQuery为原始查询，对应原始的相关性算分
                    new FunctionScoreQueryBuilder.FilterFunctionBuilder[]{
          //第二个形参，function score数组，里面有个function score元素
                            new FunctionScoreQueryBuilder.FilterFunctionBuilder(  //function score元素对象，第一个参数传入筛选字段
                                    QueryBuilders.termQuery("isAD", true),   //不再用酒店品牌筛选，而是isAD字段
                                    ScoreFunctionBuilders.weightFactorFunction(10)  //算分函数，用默认的乘法，权重为10
                            )
                    });
            request.source().query(functionScoreQuery);
    
    
        }
    
        private PageResult handleResponse(SearchResponse response) {
        
            SearchHits searchHits = response.getHits();
            long total = searchHits.getTotalHits().value;
            SearchHit[] hits = searchHits.getHits();
            List<HotelDoc> hotelDocList = Arrays.stream(hits).map(t -> {
        
                String json = t.getSourceAsString();
                HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
                //开始加入距离
                Object[] sortValues = t.getSortValues();
                if (sortValues.length > 0) {
        
                    Object sortValue = sortValues[0];
                    hotelDoc.setDistance(sortValue);
                }
                return hotelDoc;
            }).collect(Collectors.toList());
            return new PageResult(total, hotelDocList);
        }
    
        private static boolean isEmpty(String str) {
        
            return str == null || "".equals(str);
        }
    }

--------------------

最后，页面上其他地方的需求实现思路：

排序:

![在这里插入图片描述][86c9ded86ecf4b79880b3730da3c5b89.png]  
前端会传递sortBy参数，就是排序方式，后端需要判断sortBy值是什么：

*  default：相关度算分排序，这个不用管，es的默认排序策略
 *  score：根据酒店的score字段排序，也就是用户评价，降序
 *  price：根据酒店的price字段排序，就是价格，升序

高亮：

![在这里插入图片描述][e2024f1eaaca4f4eb259cd668a753824.png]

request.source()
            .query(QueryBuilders.matchQuery("all",requestParam.getKey()))
            .highlighter(new HighlightBuilder().field("name")
                    .requireFieldMatch(false)
                    .preTags("<strong>")
                    .postTags("</strong")
            );

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