ES的使用（Elasticsearch）-编程知识

ES的使用（Elasticsearch）

es是什么？
es是非关系型数据库，是分布式文档数据库，本质上是一个JSON 文本
为什么要用es?
搜索速度快，近乎是实时的存储、检索数据
怎么使用es?
1.下载es的包（环境要是jdk1.8及以上）（我的资源中有）
2.下载es的可视化界面包（我的资源中有）
3.java编写es的工具类
es与关系型数据库对比

1.下载es的包，解压，运行bat文件（windows）

下载地址：es官网下载地址
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elasticsearch.yml配置允许跨域

http.cors.enabled: true
http.cors.allow-origin: "*"

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2.下载es的可视化界面包，解压，使用命令`npm run start`

下载地址：elasticsearch-head-master es可视化工具
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打开http:localhost:9100

3.java编写es的工具类

引入es的依赖包

		<dependency><groupId>org.elasticsearch.client</groupId><artifactId>elasticsearch-rest-high-level-client</artifactId><version>6.2.4</version></dependency><dependency><groupId>org.elasticsearch.client</groupId><artifactId>elasticsearch-rest-client</artifactId><version>6.2.4</version></dependency><dependency><groupId>org.elasticsearch</groupId><artifactId>elasticsearch</artifactId><version>6.2.4</version></dependency>

package com.next.service;import lombok.extern.slf4j.Slf4j;
import org.apache.http.HttpHost;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.message.BasicHeader;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.get.GetRequest;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.get.MultiGetRequest;
import org.elasticsearch.action.get.MultiGetResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.action.update.UpdateRequest;
import org.elasticsearch.action.update.UpdateResponse;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.stereotype.Service;@Service
@Slf4j
public class ESClient implements ApplicationListener<ContextRefreshedEvent> {private final static int CONNECT_TIMEOUT = 100;private final static int SOCKET_TIMEOUT = 60 * 1000;private final static int REQUEST_TIMEOUT = SOCKET_TIMEOUT;private RestHighLevelClient restHighLevelClient; //JDK8及以上private BasicHeader[] basicHeaders;@Overridepublic void onApplicationEvent(ContextRefreshedEvent contextRefreshedEvent) {try {initClient();} catch (Exception e) {log.error("es client init exception", e);try {Thread.sleep(1000);} catch (Exception e1) {}initClient();}}private void initClient() {log.info("es client init start");//请求头时允许的格式basicHeaders = new BasicHeader[]{new BasicHeader("Accept", "application/json;charset=UTF-8")};//es客户端连接设置初始化RestClientBuilder builder = RestClient.builder(new HttpHost("127.0.0.1", 9200, "http"));builder.setDefaultHeaders(basicHeaders)//设置相关超时间配置.setRequestConfigCallback((RequestConfig.Builder configBuilder) -> {configBuilder.setConnectTimeout(CONNECT_TIMEOUT);configBuilder.setSocketTimeout(SOCKET_TIMEOUT);configBuilder.setConnectionRequestTimeout(REQUEST_TIMEOUT);return configBuilder;});restHighLevelClient = new RestHighLevelClient(builder);log.info("es client init end");}//es新增操作public IndexResponse index(IndexRequest indexRequest) throws Exception {try {return restHighLevelClient.index(indexRequest);} catch (Exception e) {log.error("es.index exception,indexRequest:{}", indexRequest, e);throw e;}}//更新操作public UpdateResponse update(UpdateRequest updateRequest) throws Exception {try {return restHighLevelClient.update(updateRequest, basicHeaders);} catch (Exception e) {log.error("es.update exception,updateRequest:{}", updateRequest, e);throw e;}}//查询public GetResponse get(GetRequest getRequest) throws Exception {try {return restHighLevelClient.get(getRequest, basicHeaders);} catch (Exception e) {log.error("es.get exception,updateRequest:{}", getRequest, e);throw e;}}//多个查询请求放在一起查public MultiGetResponse multiGet(MultiGetRequest multiGetRequest) throws Exception {try {return restHighLevelClient.multiGet(multiGetRequest);} catch (Exception e) {log.error("es.multiGet exception,getRequest:{}", multiGetRequest, e);throw e;}}/*** @desc 批量更新*/public BulkResponse bulk(BulkRequest bulkRequest) throws Exception {try {return restHighLevelClient.bulk(bulkRequest,basicHeaders);} catch (Exception e) {log.error("es.multiGet exception,bulkRequest:{}", bulkRequest, e);throw e;}}
}

es启动
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4.使用例子：

将车次信息存到es中，方便用户查询(从此地到目的地有哪些车可以乘坐)

package com.next.service;import com.alibaba.google.common.base.Splitter;
import com.alibaba.otter.canal.protocol.CanalEntry;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.next.common.TrainEsConstant;
import com.next.dao.TrainNumberDetailMapper;
import com.next.dao.TrainNumberMapper;
import com.next.model.TrainNumber;
import com.next.model.TrainNumberDetail;
import com.next.util.JsonMapper;
import lombok.extern.slf4j.Slf4j;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.get.*;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.update.UpdateRequest;
import org.elasticsearch.common.util.set.Sets;
import org.springframework.stereotype.Service;
import org.springframework.util.CollectionUtils;import javax.annotation.Resource;
import java.util.List;
import java.util.Map;
import java.util.Set;@Service
@Slf4j
public class TrainNumberService {@Resourceprivate TrainNumberMapper trainNumberMapper;@Resourceprivate TrainCacheService trainCacheService;@Resourceprivate TrainNumberDetailMapper trainNumberDetailMapper;@Resourceprivate ESClient esClient;public void handle(List<CanalEntry.Column> columns, CanalEntry.EventType eventType) throws Exception{if (eventType != CanalEntry.EventType.UPDATE) {log.info("not update,no need care");return;}int trainNumberId = 0;//获取数据库的trainNumberIdfor (CanalEntry.Column column : columns) {if (column.getName().equals("id")) {trainNumberId = Integer.parseInt(column.getValue());break;}}TrainNumber trainNumber = trainNumberMapper.selectByPrimaryKey(trainNumberId);//校验是否有车次if (null == trainNumber) {log.error("not found trainNumber,trainNumberId:{}", trainNumberId);return;}List<TrainNumberDetail> detailList = trainNumberDetailMapper.getByTrainNumberId(trainNumberId);//校验是否有车次详情if (CollectionUtils.isEmpty(detailList)) {log.warn("no detail,no need care,trainNumberId:{}", trainNumber.getName());return;}//将数据写入缓存中trainCacheService.set("TN_" + trainNumber.getName(), JsonMapper.obj2String(detailList));log.info("trainNumber:{} detailList update redis", trainNumber.getName());//将数据存入es中saveES(detailList,trainNumber);log.info("trainNumber:{} detailList update es", trainNumber.getName());}//数据保存到es(客户需要查询的数据放到es--->从此地到目的地有哪些车可以乘坐)private void saveES(List<TrainNumberDetail> detailList, TrainNumber trainNumber) throws Exception{/*** A-B fromStationId- toStationId* 例：北京到大连有多少趟车?* 根据车站的开始结束站，去找车次，即根据fromStationId- toStationId获取到 trainNumberId1,trainNumberId2。。。。* trainNumber: A->B->C* D386:北京->锦州->大连* D387:北京->鞍山->大连** 拆分如下* D386: 北京-锦州 锦州-大连 北京-大连* D387: 北京-鞍山 鞍山-大连 北京-大连*/List<String> list = Lists.newArrayList();int fromStationId = trainNumber.getFromStationId();if (detailList.size() == 1) {//单段int toStationId = trainNumber.getToStationId();list.add(fromStationId + "_" + toStationId);} else {//多段,枚举所有的车次,要保证多段有序for (int i = 0; i < detailList.size(); i++) {//获取开始车站idint tempFromStationId = detailList.get(i).getFromStationId();for (int j = i; j < detailList.size(); j++) {//获取到达车站idint tempToStationId = detailList.get(j).getToStationId();list.add(tempFromStationId+"_"+tempToStationId);}}}//检查数据是否已经存在，存在则不新增，不存在则新增//★如果是for循环里面的话，要封装成批量操作IOMultiGetRequest multiGetRequest = new MultiGetRequest();BulkRequest bulkRequest = new BulkRequest();for(String item:list){multiGetRequest.add(new MultiGetRequest.Item(TrainEsConstant.INDEX,TrainEsConstant.TYPE,item));}//获取处理后的结果MultiGetResponse multiGetItemResponses = esClient.multiGet(multiGetRequest);for(MultiGetItemResponse itemResponse:multiGetItemResponses.getResponses()){if(itemResponse.isFailed()){log.error("multiGet item failed,itemResponse:{}",itemResponse);continue;}GetResponse getResponse = itemResponse.getResponse();if(getResponse == null){log.error("multiGet item is null,itemResponse:{}",itemResponse);continue;}//存储更新es的数据，新增用source传入数据  更新用doc传入数据Map<String,Object> dataMap = Maps.newHashMap();Map<String,Object> map = getResponse.getSourceAsMap();if(!getResponse.isExists() || map == null){//add indexdataMap.put(TrainEsConstant.COLUMN_TRAIN_NUMBER,trainNumber.getName());IndexRequest indexRequest = new IndexRequest(TrainEsConstant.INDEX,TrainEsConstant.TYPE,getResponse.getId()).source(dataMap);bulkRequest.add(indexRequest);continue;}//里面是车次信息 trainNumberId1,trainNumberId2。。。。，需要拆分String origin = (String) map.get(TrainEsConstant.COLUMN_TRAIN_NUMBER);Set<String> set = Sets.newHashSet(Splitter.on(",").trimResults().omitEmptyStrings().split(origin));if(!set.contains(trainNumber.getName())){//update indexdataMap.put(TrainEsConstant.COLUMN_TRAIN_NUMBER,origin+","+trainNumber.getName());UpdateRequest updateRequest = new UpdateRequest(TrainEsConstant.INDEX,TrainEsConstant.TYPE,getResponse.getId()).doc(dataMap);bulkRequest.add(updateRequest);}}//批量更新es的数据(bulkResponse是批量对象转成string打印日志)BulkResponse bulkResponse = esClient.bulk(bulkRequest);log.info("es bulk response:{}",JsonMapper.obj2String(bulkResponse));if(bulkResponse.hasFailures()){throw new RuntimeException("es bulk failure");}}}