ElasticSearch搜索引擎在JavaWeb项目中的应用

近几篇ElasticSearch系列：

一、前言

前四篇简单介绍了ElasticSearch（以下简称ES）在阿里云服务器Linux系统上的部署配置等。本篇将简述一下ES在JavaWeb项目中的应用。本项目前端框架是Vue.js，前后端数据交互采用是常用的SSM框架，项目管理工具为Maven，ES为6.3.2版本。

二、正文

1、ES在Maven中添加相应依赖，如下所示：

 1 <dependency>
 2     <groupId>org.elasticsearch</groupId>
 3     <artifactId>elasticsearch</artifactId>
 4     <version>6.3.2</version>
 5 </dependency>
 6 <dependency>
 7     <groupId>org.elasticsearch.client</groupId>
 8     <artifactId>transport</artifactId>
 9     <version>6.3.2</version>
10 </dependency>

2、@Configuration注解新建的 “ElasticSearchConfig” 类，用来初始化ES客户端TransportClient连接，通过setting来创建，若不指定则默认链接的集群名为elasticsearch，如下图所示：

 1 @Configuration
 2 public class ElasticSearchConfig {
 3 
 4     @Bean
 5     public TransportClient client() throws UnknownHostException {
 6         Settings settings = Settings.builder().build();
 7         TransportClient client = new PreBuiltTransportClient(settings)
 8                 .addTransportAddress(new TransportAddress(InetAddress.getByName("部署ES的IP地址"), 9300));
 9         return client;
10     }
11 }

3、jsp里首先需要导入jquery与Vue，然后css样式仅供参考，如下图所示：

 1 <div id="search_main" style="position: relative;top: -360px;left: -200px;width: 100%;height: 50px;text-align: center">
 2     <input id="search_input1" type="text" name="search1" placeholder="请输入企业名称。如“阿里巴巴”或“alibaba”"
 3            style="height: 50px;width: 720px;border: none;font-size: 18px;" onkeypress="EnterPress(event)" onkeydown="EnterPress()"
 4            v-model="searchText" v-on:keyup="showName(searchText)"/>
 5     <img id="voice" src="icon/voice1.png" width="35" height="35" style="position: absolute;left: 1145px;top: 7px;"/>
 6     <button id="search_button1" type="button" style="position: relative;left: -4px;top: 1px;height: 50px;width: 100px;border: none;background-color: #1db5ee">
 7         <font size="4" color="white" style="align-content: center">搜索</font>
 8     </button>
 9     <font id="searchType" style="display: none">企业名</font>
10     <div id="parentRelationSearch" v-for="(company, cIndex) in companyList" style="position: relative;top: 0px;left: 474px;height: auto;width: 719px;background-color: #ffffff;z-index: 99">
11         <div class="relationSearch" v-on:click="putVal(company.name)" v-on:mouseenter="mouseEnter($event)" v-on:mouseleave="mouseLeave($event)" style="position: relative;top: 0px;left: 0px;width: 100%;height: 35px;border-bottom: 1px solid #e8e8e8;line-height: 35px;">
12             <font size="2" style="position: absolute;left: 5px">{{company.name}}</font>
13             <font size="1.5" style="position: absolute;left: 92%;">{{company.score}}</font>
14         </div>
15     </div>
16 </div>

4、id为search_main的元素为Vue实例挂载的元素节点，以及showName函数（ajax请求）为keyup事件，putVal函数（将用户选中的元素值赋值给搜索框）为click事件，mouseEnter、mouseLeave函数分别为mouseenter、mouseleave事件，如下图所示：

 1 var vm1 = new Vue({
 2     el: '#search_main',
 3     data: {
 4         searchText: "",
 5         companyList: [],
 6     },
 7     mounted: function () {
 8         this.showName();
 9         this.putVal();
10         this.mouseEnter();
11         this.mouseLeave();
12     },
13     methods: {
14         putVal: function (val) {
15             $("#search_input1").val(val);
16             $(".relationSearch").hide();
17             document.getElementById("search_input1").focus();
18         },
19         showName: function (key) {
20             console.log(key);
21             if (key.length != 0) {
22                 var searchType = document.getElementById("searchType").innerText;
23                 if (searchType == "全部" || searchType == "企业名") {
24                     $(".relationSearch").show();
25                     var _this = this;
26                     this.$http.get("auto_think.do?key=" + key).then(function (jsonResult) {
27                         _this.companyList = (jsonResult.body);
28                     });
29                 }
30             } else {
31                 $(".relationSearch").hide();
32             }
33         },
34         mouseEnter: function ($event) {
35             $event.currentTarget.className = "relationSearch searchActive";
36         },
37         mouseLeave: function ($event) {
38             $event.currentTarget.className = "relationSearch";
39         }
40     }
41 });

上述mouseEnter函数是用于动态添加class，用以实现鼠标移入则修改元素的背景功能：

1 .searchActive{
2     background-color:#e8e8e8;
3 }

5、QueryBuilder是ES提供的一个查询接口，进行单个匹配值为key的文档。SearchRequestBuilder根据索引与类型构造查询请求，设置查询条件和分页参数，再获取返回值并进行处理，最后返回，如下图所示：

 1 package controller;
 2 
 3 import entity.ElasticSearchResult;
 4 import org.elasticsearch.action.index.IndexResponse;
 5 import org.elasticsearch.action.search.SearchRequestBuilder;
 6 import org.elasticsearch.action.search.SearchResponse;
 7 import org.elasticsearch.client.transport.TransportClient;
 8 import org.elasticsearch.common.xcontent.XContentBuilder;
 9 import org.elasticsearch.common.xcontent.XContentFactory;
10 import org.elasticsearch.index.query.QueryBuilder;
11 import org.elasticsearch.index.query.QueryBuilders;
12 import org.elasticsearch.search.SearchHit;
13 import org.elasticsearch.search.SearchHits;
14 import org.springframework.beans.factory.annotation.Autowired;
15 import org.springframework.stereotype.Controller;
16 import org.springframework.web.bind.annotation.GetMapping;
17 import org.springframework.web.bind.annotation.RequestParam;
18 import org.springframework.web.bind.annotation.ResponseBody;
19 
20 import java.io.IOException;
21 import java.math.BigDecimal;
22 import java.util.ArrayList;
23 import java.util.List;
24 
25 @Controller
26 public class ElasticSearchController {
27 
28     @Autowired
29     private TransportClient client;
30 
31     //搜索自动联想
32     @GetMapping("/auto_think.do")
33     @ResponseBody
34     public List<ElasticSearchResult> findIndexRecordByName(@RequestParam(name = "key") String key) {
35         // 构造查询请求
36         QueryBuilder bq = QueryBuilders.matchQuery("name.pinyin", key);
37         SearchRequestBuilder searchRequest = client.prepareSearch("medcl").setTypes("folks");
38 
39         // 设置查询条件和分页参数
40         int start = 0;
41         int size = 5;
42         searchRequest.setQuery(bq).setFrom(start).setSize(size);
43 
44         // 获取返回值，并进行处理
45         SearchResponse response = searchRequest.execute().actionGet();
46         SearchHits shs = response.getHits();
47         List<ElasticSearchResult> esResultList = new ArrayList<>();
48         for (SearchHit hit : shs) {
49             ElasticSearchResult esResult = new ElasticSearchResult();
50             double score = hit.getScore();
51             BigDecimal b = new BigDecimal(score);
52             score = b.setScale(3, BigDecimal.ROUND_HALF_UP).doubleValue();
53             String name = (String) hit.getSourceAsMap().get("name");
54             System.out.println("score:" + score + "name:" + name);
55             esResult.setScore(score);
56             esResult.setName(name);
57             esResultList.add(esResult);
58         }
59         return esResultList;
60     }
61     
62 }

下述为ElasticSearchResult实体类：

 1 package entity;
 2 
 3 public class ElasticSearchResult {
 4 
 5     private double score;
 6 
 7     private String name;
 8 
 9     public ElasticSearchResult() {
10     }
11 
12     public double getScore() {
13         return score;
14     }
15 
16     public void setScore(double score) {
17         this.score = score;
18     }
19 
20     public String getName() {
21         return name;
22     }
23 
24     public void setName(String name) {
25         this.name = name;
26     }
27 }

再附上向指定索引与类型添加、删除、更新文档函数代码，如下所示：

 1 /**
 2  * 添加文档
 3  * @param name
 4  */
 5 public void addByName(String name) {
 6     try {
 7         XContentBuilder content = XContentFactory.jsonBuilder()
 8                 .startObject().field("name", name).endObject();
 9         client.prepareIndex("medcl", "folks")
10                 .setSource(content).get();
11         System.out.println("ElasticSearch添加文档成功。");
12     } catch (IOException e) {
13         System.out.println("ElasticSearch添加文档出错。");
14         e.printStackTrace();
15     }
16 }
17 
18 /**
19  * 删除文档
20  * @param name
21  */
22 public void deleteByName(String name) {
23     BulkRequestBuilder bulkRequest = client.prepareBulk();
24     SearchResponse response = client.prepareSearch("medcl").setTypes("folks")
25             .setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
26             .setQuery(QueryBuilders.termQuery("name", name))
27             .setFrom(0).setSize(20).setExplain(true).execute().actionGet();
28     for(SearchHit hit : response.getHits()){
29         String id = hit.getId();
30         bulkRequest.add(client.prepareDelete("medcl", "folks", id).request());
31     }
32     BulkResponse bulkResponse = bulkRequest.get();
33 
34     if (bulkResponse.hasFailures()) {
35         System.out.println("ElasticSearch删除文档出错。");
36         for(BulkItemResponse item : bulkResponse.getItems()){
37             System.out.println(item.getFailureMessage());
38         }
39     }else {
40         System.out.println("ElasticSearch删除文档成功。");
41     }
42 }
43 
44 /**
45  * 更新文档
46  * @param beforeName
47  * @param afterName
48  */
49 public void updateByName(String beforeName,String afterName){
50     SearchResponse response = client.prepareSearch("medcl").setTypes("folks")
51             .setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
52             .setQuery(QueryBuilders.termQuery("name", beforeName))
53             .setFrom(0).setSize(20).setExplain(true).execute().actionGet();
54     try {
55         for(SearchHit hit : response.getHits()){
56             UpdateRequest updateRequest = new UpdateRequest();
57             updateRequest.index("medcl");
58             updateRequest.type("folks");
59             updateRequest.id(hit.getId());
60             updateRequest.doc(XContentFactory.jsonBuilder().startObject().field("name",afterName).endObject());
61             client.update(updateRequest).get();
62         }
63         System.out.println("ElasticSearch更新文档成功。");
64     }catch (Exception e){
65         System.out.println("ElasticSearch更新文档出错。");
66         e.printStackTrace();
67     }
68 }