ES的使用（Elasticsearch）

q琦一2023-12-30 10:48

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


elasticsearch.yml配置允许跨域

yaml 复制代码 
http.cors.enabled: true
http.cors.allow-origin: "*"

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

打开http:localhost:9100

3.java编写es的工具类

引入es的依赖包

xml 复制代码 
		<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>
java 复制代码 
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;

    @Override
    public 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

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)

java 复制代码 
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 {

    @Resource
    private TrainNumberMapper trainNumberMapper;

    @Resource
    private TrainCacheService trainCacheService;

    @Resource
    private TrainNumberDetailMapper trainNumberDetailMapper;

    @Resource
    private 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trainNumberId
        for (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id
                int tempFromStationId = detailList.get(i).getFromStationId();
                for (int j = i; j < detailList.size(); j++) {
                    //获取到达车站id
                    int 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IO
        MultiGetRequest 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 index
                dataMap.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 index
                dataMap.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");
        }

    }


}

车次表
车次明细表

修改数据库中车次表的信息会将数据处理后（出发站-到达站 车次号）存入es

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