ElasticSearch实战：仿京东搜索

1. 项目搭建

1.1 elasticSearch依赖版本

首先修改Spring Boot版本为2.2.5

1.2 application.properties文件

server.port=9090
# 关闭thymeleaf的缓存
spring.thymeleaf.cache=false

1.3 导入静态资源

1.4 创建首页映射

package com.rgh.controller;
@Controller
public class IndexController {
    @GetMapping({"/","/index"})
    public String index(){
        return "index";
    }
}

1.5 访问首页

2. 数据爬取

爬取京东的数据

2.1 导入jsoup依赖

用来解析网页

<dependency>
    <groupId>org.jsoup</groupId>
    <artifactId>jsoup</artifactId>
    <version>1.10.2</version>
</dependency>

package com.rgh.util;
@Component
public class HtmlParseUtil {
    public List<Content> parseJD(String keywords) throws Exception {
        //获取请求
        String url = "https://search.jd.com/Search?keyword="+keywords;
        //解析网页。(Jsoup返回Document就是浏览器Document对象)
        Document document = Jsoup.parse(new URL(url), 30000);
        //所有你在js中可以使用的方法，这里都能用
        Element element = document.getElementById("J_goodsList");
        //获取所有的li元素
        Elements elements = element.getElementsByTag("li");
        ArrayList<Content> goodsList = new ArrayList<>();
        //获取元素中的内容，这里el 就是每一个li标签了
        for(Element el : elements){
            //关于这种图片特别多的网站，所有的图片都是延迟加载的
            String img = el.getElementsByTag("img").eq(0).attr("source-data-lazy-img");
            String price = el.getElementsByClass("p-price").eq(0).text();
            String title = el.getElementsByClass("p-name").eq(0).text();
            Content content = new Content();
            content.setTitle(title);
            content.setImg(img);
            content.setPrice(price);
            goodsList.add(content);
        }
        return goodsList;
    }
}

2.2 创建对应的实体类

package com.rgh.pojo;
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Content {
    private String title;
    private String img;
    private String price;
}

2.3 创建配置类

package com.rgh.config;
@Configuration
public class ElasticSearchClientConfig {
    @Bean
    public RestHighLevelClient restHighLevelClient(){
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("127.0.0.1",9200,"http")
                )
        );
        return client;
    }
}

2.4 业务编写

导入解析JSON的依赖

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.62</version>
</dependency>

前提:在es中创建一个jd_goods的索引

解析数据放入es索引中

package com.rgh.service;
@Service
public class ContentService {
    @Autowired
    private RestHighLevelClient restHighLevelClient;

    public Boolean parseContent(String keywords) throws Exception {
        List<Content> contents = new HtmlParseUtil().parseJD(keywords);
        BulkRequest bulkRequest = new BulkRequest();
        bulkRequest.timeout("2m");
        for(int i = 0 ; i< contents.size();i++){
            bulkRequest.add(
                new IndexRequest("jd_goods")
                .source(JSON.toJSONString(contents.get(i)), XContentType.JSON)
            );
        }
        BulkResponse bulk = restHighLevelClient.bulk(bulkRequest, RequestOptions.DEFAULT);
        return !bulk.hasFailures();
    }

2.5 请求编写

package com.rgh.controller;
@RestController
public class ContentController {

    @Autowired
    private ContentService contentService;

    @GetMapping("/parse/{keyword}")
    public Boolean parse(@PathVariable("keyword") String keyword) throws Exception{
        return contentService.parseContent(keyword);
    }

3. 实现搜索功能

3.1 分页+搜索+高亮业务编写

package com.rgh.service;
@Service
public class ContentService {
    @Autowired
    private RestHighLevelClient restHighLevelClient;

    //获取这些数据实现搜索功能
    public List<Map<String,Object>> searchPage(String keyword,int pageNo,int pageSize) throws IOException {
        if(pageNo<=1){
            pageNo = 1;
        }
        //条件搜索
        SearchRequest searchRequest = new SearchRequest("jd_goods");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        //分页
        sourceBuilder.from(pageNo);
        sourceBuilder.size(pageSize);
        //精准匹配
        TermQueryBuilder title = QueryBuilders.termQuery("title", keyword);
        sourceBuilder.query(title);
        sourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS));
        //高亮
        HighlightBuilder highlightBuilder = new HighlightBuilder();
        highlightBuilder.field("title");
        highlightBuilder.requireFieldMatch(false);//多个高亮显示
        highlightBuilder.preTags("<span style= 'color:red'>");
        highlightBuilder.postTags("</span>");
        sourceBuilder.highlighter(highlightBuilder);
        //执行搜索
        searchRequest.source(sourceBuilder);
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        //解析结果
        ArrayList<Map<String,Object>> list = new ArrayList<>();
        for(SearchHit hit : search.getHits().getHits()){
            Map<String, HighlightField> highlightFields = hit.getHighlightFields();
            HighlightField title1 = highlightFields.get("title");
            Map<String, Object> sourceAsMap = hit.getSourceAsMap();//原来的结果
            //解析高亮的字段，将原来的字段换为我们高亮的字段即可
            if(title1 != null){
                Text[] fragments = title1.fragments();
                String n_title = "";
                for (Text text : fragments) {
                    n_title += text;
                }
                sourceAsMap.put("title",n_title);
            }
            list.add(sourceAsMap);
        }
        return list;
    }
}

3.2 请求编写

package com.rgh.controller;
@RestController
public class ContentController {

    @Autowired
    private ContentService contentService;

    @GetMapping("/search/{keyword}/{pageNo}/{pageSize}")
    public List<Map<String,Object>> search(@PathVariable("keyword") String keyword,
                                           @PathVariable("pageNo") int pageNo,
                                           @PathVariable("pageSize") int pageSize) throws IOException {
        return contentService.searchPage(keyword,pageNo,pageSize);
    }
}

4. 前端请求

4.1 引入js文件

<script th:src="@{/js/axios.min.js}"></script>
<script th:src="@{/js/vue.min.js}"></script>

4.2 Vue

4.3 页面响应成功

参考：B站狂神说Java