ElasticSearch搜索引擎在JavaWeb项目中的应用
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。
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：
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 }
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！
