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ElasticSearch搜索引擎在JavaWeb项目中的应用
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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！
