ElasticSearch搜索引擎在JavaWeb项目中的应用

近几篇ElasticSearch系列：

1、阿里云服务器Linux系统安装配置ElasticSearch搜索引擎

2、Linux系统中ElasticSearch搜索引擎安装配置Head插件

3、ElasticSearch搜索引擎安装配置中文分词器IK插件

4、ElasticSearch搜索引擎安装配置拼音插件pinyin

5、ElasticSearch搜索引擎在JavaWeb项目中的应用

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：

 <dependency>
     <groupId>org.elasticsearch</groupId>
     <artifactId>elasticsearch</artifactId>
     <version>6.3.2</version>
 </dependency>
 <dependency>
     <groupId>org.elasticsearch.client</groupId>
     <artifactId>transport</artifactId>
     <version>6.3.2</version>
 </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：

 @Configuration
 public class ElasticSearchConfig {

     @Bean
     public TransportClient client() throws UnknownHostException {
         Settings settings = Settings.builder().build();
         TransportClient client = new PreBuiltTransportClient(settings)
                 .addTransportAddress(new TransportAddress(InetAddress.getByName("部署ES的IP地址"), 9300));
         return client;
     }
 }

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：

 <div id="search_main" style="position: relative;top: -360px;left: -200px;width: 100%;height: 50px;text-align: center">
     <input id="search_input1" type="text" name="search1" placeholder="请输入企业名称。如“阿里巴巴”或“alibaba”"
            style="height: 50px;width: 720px;border: none;font-size: 18px;" onkeypress="EnterPress(event)" onkeydown="EnterPress()"
            v-model="searchText" v-on:keyup="showName(searchText)"/>
     <img id="voice" src="icon/voice1.png" width="35" height="35" style="position: absolute;left: 1145px;top: 7px;"/>
     <button id="search_button1" type="button" style="position: relative;left: -4px;top: 1px;height: 50px;width: 100px;border: none;background-color: #1db5ee">
         <font size="4" color="white" style="align-content: center">搜索</font>
     </button>
     <font id="searchType" style="display: none">企业名</font>
     <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">
         <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;">
             <font size="2" style="position: absolute;left: 5px">{{company.name}}</font>
             <font size="1.5" style="position: absolute;left: 92%;">{{company.score}}</font>
         </div>
     </div>
 </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：

 var vm1 = new Vue({
     el: '#search_main',
     data: {
         searchText: "",
         companyList: [],
     },
     mounted: function () {
         this.showName();
         this.putVal();
         this.mouseEnter();
         this.mouseLeave();
     },
     methods: {
         putVal: function (val) {
             $("#search_input1").val(val);
             $(".relationSearch").hide();
             document.getElementById("search_input1").focus();
         },
         showName: function (key) {
             console.log(key);
             if (key.length != 0) {
                 var searchType = document.getElementById("searchType").innerText;
                 if (searchType == "全部" || searchType == "企业名") {
                     $(".relationSearch").show();
                     var _this = this;
                     this.$http.get("auto_think.do?key=" + key).then(function (jsonResult) {
                         _this.companyList = (jsonResult.body);
                     });
                 }
             } else {
                 $(".relationSearch").hide();
             }
         },
         mouseEnter: function ($event) {
             $event.currentTarget.className = "relationSearch searchActive";
         },
         mouseLeave: function ($event) {
             $event.currentTarget.className = "relationSearch";
         }
     }
 });

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：

 .searchActive{
     background-color:#e8e8e8;
 }

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：

 package controller;

 import entity.ElasticSearchResult;
 import org.elasticsearch.action.index.IndexResponse;
 import org.elasticsearch.action.search.SearchRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.client.transport.TransportClient;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.search.SearchHits;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.ResponseBody;

 import java.io.IOException;
 import java.math.BigDecimal;
 import java.util.ArrayList;
 import java.util.List;

 @Controller
 public class ElasticSearchController {

     @Autowired
     private TransportClient client;

     //搜索自动联想
     @GetMapping("/auto_think.do")
     @ResponseBody
     public List<ElasticSearchResult> findIndexRecordByName(@RequestParam(name = "key") String key) {
         // 构造查询请求
         QueryBuilder bq = QueryBuilders.matchQuery("name.pinyin", key);
         SearchRequestBuilder searchRequest = client.prepareSearch("medcl").setTypes("folks");

         // 设置查询条件和分页参数
         int start = 0;
         int size = 5;
         searchRequest.setQuery(bq).setFrom(start).setSize(size);

         // 获取返回值，并进行处理
         SearchResponse response = searchRequest.execute().actionGet();
         SearchHits shs = response.getHits();
         List<ElasticSearchResult> esResultList = new ArrayList<>();
         for (SearchHit hit : shs) {
             ElasticSearchResult esResult = new ElasticSearchResult();
             double score = hit.getScore();
             BigDecimal b = new BigDecimal(score);
             score = b.setScale(3, BigDecimal.ROUND_HALF_UP).doubleValue();
             String name = (String) hit.getSourceAsMap().get("name");
             System.out.println("score:" + score + "name:" + name);
             esResult.setScore(score);
             esResult.setName(name);
             esResultList.add(esResult);
         }
         return esResultList;
     }

 }

下述为ElasticSearchResult实体类：

 package entity;

 public class ElasticSearchResult {

     private double score;

     private String name;

     public ElasticSearchResult() {
     }

     public double getScore() {
         return score;
     }

     public void setScore(double score) {
         this.score = score;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }
 }

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：

 /**
  * 添加文档
  * @param name
  */
 public void addByName(String name) {
     try {
         XContentBuilder content = XContentFactory.jsonBuilder()
                 .startObject().field("name", name).endObject();
         client.prepareIndex("medcl", "folks")
                 .setSource(content).get();
         System.out.println("ElasticSearch添加文档成功。");
     } catch (IOException e) {
         System.out.println("ElasticSearch添加文档出错。");
         e.printStackTrace();
     }
 }

 /**
  * 删除文档
  * @param name
  */
 public void deleteByName(String name) {
     BulkRequestBuilder bulkRequest = client.prepareBulk();
     SearchResponse response = client.prepareSearch("medcl").setTypes("folks")
             .setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
             .setQuery(QueryBuilders.termQuery("name", name))
             .setFrom(0).setSize(20).setExplain(true).execute().actionGet();
     for(SearchHit hit : response.getHits()){
         String id = hit.getId();
         bulkRequest.add(client.prepareDelete("medcl", "folks", id).request());
     }
     BulkResponse bulkResponse = bulkRequest.get();

     if (bulkResponse.hasFailures()) {
         System.out.println("ElasticSearch删除文档出错。");
         for(BulkItemResponse item : bulkResponse.getItems()){
             System.out.println(item.getFailureMessage());
         }
     }else {
         System.out.println("ElasticSearch删除文档成功。");
     }
 }

 /**
  * 更新文档
  * @param beforeName
  * @param afterName
  */
 public void updateByName(String beforeName,String afterName){
     SearchResponse response = client.prepareSearch("medcl").setTypes("folks")
             .setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
             .setQuery(QueryBuilders.termQuery("name", beforeName))
             .setFrom(0).setSize(20).setExplain(true).execute().actionGet();
     try {
         for(SearchHit hit : response.getHits()){
             UpdateRequest updateRequest = new UpdateRequest();
             updateRequest.index("medcl");
             updateRequest.type("folks");
             updateRequest.id(hit.getId());
             updateRequest.doc(XContentFactory.jsonBuilder().startObject().field("name",afterName).endObject());
             client.update(updateRequest).get();
         }
         System.out.println("ElasticSearch更新文档成功。");
     }catch (Exception e){
         System.out.println("ElasticSearch更新文档出错。");
         e.printStackTrace();
     }
 }

最后附上功能演示效果图，如下图所示：

至此是对ElasticSearch搜索引擎在JavaWeb项目中的应用的一个简单介绍。

如有疏漏错误之处，还请不吝赐教！