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ElasticSearch的API(java/scala)

• 大数据, 开源, 研发管理, 移动开发, 编程笔记

这里小编先将需要的pom.xml的依赖提供给大家：（根据自己的版本进行修改）

<properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
        <spark.version>2.3.2</spark.version>
    </properties>

    <dependencies>
        <dependency><!-- 依赖管理，有选择的继承-->
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
            <version>6.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>2.10.3</version>
        </dependency>
        <dependency>
            <groupId>org.json</groupId>
            <artifactId>json</artifactId>
            <version>20180813</version>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch-hadoop</artifactId>
            <version>6.2.4</version>
        </dependency>

        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-core_2.11</artifactId>
            <version>${spark.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-sql_2.11</artifactId>
            <version>${spark.version}</version>
        </dependency>
    </dependencies>

1. 创建ES的编程入口

  主要是提供一个Utils，通过读取配置文件进行创建ES的编程入口。
#elasticSearch.conf

elastic.host=192.168.130.131
elastic.port=9300
elastic.cluster.name=zzy-application

#Constants

public interface Constants {
    String ELASTIC_HOST = "elastic.host";
    String ELASTIC_PORT="elastic.port";
    String ELASTIC_CLUSTER_NAME = "elastic.cluster.name";
}

#ElasticSearchUtil

import com.zy.es.constant.Constants;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Setting;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.io.IOException;
import java.io.InputStream;
import java.net.InetAddress;
import java.util.Properties;

/**
 * 一般情况下的工具类都是单例
 * 里面若干方法一般都是static
 * 如果在连接集群的时候，集群的名称对应不上：
 *  NoNodeAvailableException[None of the configured nodes are available:
 */
public class ElasticSearchUtil {
    private static TransportClient client;
    private static Properties ps;
    static {
        try {
            InputStream resourceAsStream = ElasticSearchUtil.class.getClassLoader().getResourceAsStream("elasticsearch.conf");
            ps =new Properties();
            ps.load(resourceAsStream);
            String host=ps.getProperty(Constants.ELASTIC_HOST);
            int port = Integer.parseInt(ps.getProperty(Constants.ELASTIC_PORT));
            String clusterName=ps.getProperty(Constants.ELASTIC_CLUSTER_NAME);
            Settings settings =Settings.builder()
                    .put("cluster.name",clusterName)
                    .build();
            client=new PreBuiltTransportClient(settings);
            //这里可以有多个，集群模式
            TransportAddress ta=new TransportAddress(
                    InetAddress.getByName(host),
                    port
            );
            //addTransportAddresses(TransportAddress... transportAddress)，参数为一个可变参数
            client.addTransportAddresses(ta);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static TransportClient getTransportClient(){
        return client;
    }
    public static void close(TransportClient client){
        if(client!=null){
            client.close();
        }
    }
}

2. 创建索引

  小编这里提供了json、map、javabean、XContentBuilder四种创建方式。

import java.util

import com.zy.es.pojo.Book
import com.zy.es.utils.ElasticSearchUtil
import org.elasticsearch.action.index.IndexResponse
import org.elasticsearch.cluster.metadata.MetaData.XContentContext
import org.elasticsearch.common.xcontent.{XContentBuilder, XContentType}
import org.elasticsearch.common.xcontent.json.JsonXContent
import org.json.JSONObject

object createIndex {
  private var index="library"
  private var `type`="books"
  private val client = ElasticSearchUtil.getTransportClient()
  def main(args: Array[String]): Unit = {
    createIndexByJson()
    //createIndexByMap()
   // createIndexByBean()
   // createIndexByXContentBuilder()
    //关闭es连接对象
    ElasticSearchUtil.close(client)
  }

  /**
    * 1.通过json方式创建
    * java.lang.IllegalArgumentException: The number of object passed must be even but was [1]
    * 在es5.x以上，使用XContentType.JSON来制定即可
    *setSource(json.toString(),XContentType.JSON)  必须指定第二个参数。
    */
  def createIndexByJson()={
    val json=new JSONObject
    json.put("name","我爱你中国")
    json.put("author","周迅")
    json.put("date","2018-6-6")
    //返回创建后的结果
    var response: IndexResponse = client.prepareIndex(index, `type`, "9")
      .setSource(json.toString, XContentType.JSON).get()
    //查看版本
    println(response.getVersion)
  }

  /**
    * 2.map方式
    */
  def createIndexByMap(): Unit ={
    val sourceMap=new util.HashMap[String,String]()
    sourceMap.put("name","朝花夕拾")
    sourceMap.put("author","鲁迅")
    sourceMap.put("date","2009-4-5")

    var response: IndexResponse = client.prepareIndex(index, `type`, "2").setSource(sourceMap)
      .get()
    //查看版本
    println(response.getVersion)
  }

  /**
    * 3.使用普通的javabean
    */
  def createIndexByBean()={
    val book:Book=new Book("斗破苍穹","天蚕土豆","2012-2-6");
    val json=new JSONObject(book)
    //返回创建后的结果
    var response: IndexResponse = client.prepareIndex(index, `type`, "3")
      .setSource(json.toString, XContentType.JSON).get()
    //查看版本
    println(response.getVersion)
  }

  /**
    * 4.XContentBuilder方式
    */
  def createIndexByXContentBuilder()={
    var builder: XContentBuilder = JsonXContent.contentBuilder()
    builder.startObject()
      .field("name","西游记")
      .field("author","吴承恩")
      .field("version","1.0")
      .endObject()
    var response: IndexResponse = client.prepareIndex(index, `type`,"4").setSource(builder)
      .get()
    println(response.getVersion)
  }
}

3.删除数据 & 更新数据 &批量处理

  小编这里提供了删除数据，更新数据，批量操作。

import java.util

import com.zy.es.utils.ElasticSearchUtil
import org.elasticsearch.action.bulk.BulkResponse
import org.elasticsearch.action.delete.DeleteResponse
import org.elasticsearch.action.update.{UpdateRequestBuilder, UpdateResponse}
import org.elasticsearch.common.xcontent.{XContentBuilder, XContentType}
import org.elasticsearch.common.xcontent.json.JsonXContent
import org.json.JSONObject

object ElasticsearchCRUD {
  private var index="library"
  private var `type`="books"
  private val client = ElasticSearchUtil.getTransportClient()
  def main(args: Array[String]): Unit = {
    //删除数据
    testDelete()
    //更新
    //testUpdate()
    //批量操作
    //testBulk()

    //关闭连接对象
    ElasticSearchUtil.close(client)
  }
  //删除数据
  def testDelete()={
    var response: DeleteResponse = client.prepareDelete(index, `type`, "2").get()
    println("version:"+response.getVersion)
  }
  //更新
  def testUpdate()={
    var builder: XContentBuilder = JsonXContent.contentBuilder()
    builder.startObject()
      .field("version","3.0")
      .endObject()
    var response: UpdateResponse  = client.prepareUpdate(index, `type`, "4")
      .setDoc(builder).get()
    println("version:"+response.getVersion)
  }

  //批量操作
  def testBulk()={
    val map=new util.HashMap[String,String]()
    map.put("name","无双")
    map.put("author","周润发")
    map.put("version","2")
    val json=new JSONObject
    json.put("name","红楼梦")
    json.put("author","曹雪芹")
    json.put("version","1.0")
    var responses: BulkResponse = client.prepareBulk().add(client.prepareIndex(index, `type`, "7")
      .setSource(map))
      .add(client.prepareIndex(index, `type`, "8").setSource(json.toString(),XContentType.JSON))
      .get()
    for(response <-responses.getItems){
      print(response.getVersion)
    }
  }
}

4.全文索引、分页索引、高亮显示

import java.util

import com.zy.es.utils.ElasticSearchUtil
import org.elasticsearch.action.search.{SearchResponse, SearchType}
import org.elasticsearch.index.query.QueryBuilders
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder
import org.elasticsearch.search.{SearchHit, SearchHits}
import org.json.JSONObject

import scala.collection.JavaConversions

object testSearch {
  private var index="library"
  private var `type`="books"
  private val client = ElasticSearchUtil.getTransportClient()
  def main(args: Array[String]): Unit = {
    //全文索引
    //fullTextSearch()
    //分页索引
    //pagingSearch()
    //高亮索引
    highlightSearch()
  }
  //全文索引
  def fullTextSearch()={
    val json=new JSONObject()
    val response = client.prepareSearch(index) //设置检索的类型
      .setSearchType(SearchType.DEFAULT) //设置检索的类型
      .setQuery(QueryBuilders.matchQuery("author", "天蚕土豆")) //设置检索方式
      .get()

    val hits = response.getHits  //获取检索结果
    println("totals:"+hits.getTotalHits)  //检索出的数据的个数
    println("maxSource"+hits.getMaxScore) //最大的得分
    //查询的具体的内容
    val myhits = hits.getHits
    for(hit <- myhits){
      val index = hit.getIndex
      val id = hit.getId
      val `type` = hit.getType
      val source =hit.getSourceAsString
      val score=hit.getScore
      json.put("_index",index)
      json.put("_id",id)
      json.put("_type",`type`)
      json.put("_score", score )
      json.put("_source",new JSONObject(source))
      println(json.toString())
    }
  }

  //分页索引
  //分页查询：查询第num页，查count条   每一页的长度*（num-1）+count
  def pagingSearch(from:Int=0,size:Int=10)={
    var response: SearchResponse = client.prepareSearch(index)
      .setSearchType(SearchType.QUERY_THEN_FETCH)
      .setQuery(QueryBuilders.matchQuery("name", "西游记"))
      .setFrom(from)
      .setSize(size)
      .get()
    val myhits: SearchHits = response.getHits
    val total=myhits.totalHits
    println("zzy为您查询出"+total+"记录：")
    val hits: Array[SearchHit] = myhits.getHits
    for (hit<-hits){
      val map: util.Map[String, AnyRef] = hit.getSourceAsMap
      val author=map.get("author")
      val name=map.get("name")
      val version=map.get("version")
      print(
        s"""
           |author:${author}
           |name:${name}
           |version:${version}
         """.stripMargin)
    }
  }

  //高亮索引
   def highlightSearch()={
     val response=client.prepareSearch(index)
       .setSearchType(SearchType.DEFAULT)
       .setQuery(QueryBuilders.matchQuery("author","周润发"))
       .highlighter(new HighlightBuilder()
         .field("author")//给哪个字段添加标签
         .preTags("<font color='red' size='20px'>")//添加的前置标签
         .postTags("</font>"))//添加的后置标签
            .get()
     val myHits = response.getHits
     val total = myHits.totalHits
     println("zzy为您查询出" + total + "记录：")
     val hits: Array[SearchHit] = myHits.getHits
     for(hit <-hits){
       //注意这里如果想要获取高亮的字段，必须使用高亮的方式获取
       val HLfields = hit.getHighlightFields
       //这里的field是设置高亮的字段名：author  highlight查询的所有的字段值（含高亮的）
       for((field,highlight)<-JavaConversions.mapAsScalaMap(HLfields)){
         var date=""
         val fragments=highlight.getFragments
         for(fragment <-fragments){
           date+=fragment.toString
         }
         print(date)
       }
     }
   }
}

5. 中文分词

（1）错误演示

首先我们现在自己的ES集群中添加一些数据：

#创建索引库
curl -H "Content-Type: application/json" -XPUT 'http://192.168.130.131:9200/chinese'
#添加数据
curl -H "Content-Type: application/json" -XPOST http://192.168.130.131:9200/chinese/fulltext/1 -d'{"content":"美国留给伊拉克的是个烂摊子吗"}'
curl -H "Content-Type: application/json" -XPOST http://192.168.130.131:9200/chinese/fulltext/2 -d'{"content":"公安部：各地校车将享最高路权"}'
curl -H "Content-Type: application/json" -XPOST http://192.168.130.131:9200/chinese/fulltext/3 -d'{"content":"中韩渔警冲突调查：韩警平均每天扣1艘中国渔船"}'
curl -H "Content-Type: application/json" -XPOST http://192.168.130.131:9200/chinese/fulltext/4 -d'{"content":"中国驻洛杉矶领事馆遭亚裔男子枪击 嫌犯已自首"}'

#然后使用不同的查询看看效果：

import com.zy.es.utils.ElasticSearchUtil
import org.elasticsearch.action.search.{SearchResponse, SearchType}
import org.elasticsearch.index.query.QueryBuilders

object ChineseParticipleSearch {
  private var index="chinese"
  private var `type`="fulltext"
  private val client = ElasticSearchUtil.getTransportClient()
  def main(args: Array[String]): Unit = {
    val response: SearchResponse =client.prepareSearch(index)
      .setSearchType(SearchType.QUERY_THEN_FETCH)
      .setQuery(QueryBuilders.matchQuery("content","中国"))
      .get()
    val myHits = response.getHits.getHits
    for(hit <- myHits){
      println(hit.getSourceAsString)
    }
  }
}

注意：我们这里使用match查询，查询了是“中国”
看看运行结果：
ElasticSearch的API(java/scala)
这里为什么美国也会被查询出来？
这是因为：原生的查询将‘中国’这个两个字分开之后在进行检索，索引会出现上图中的查询错误的情况。
那我们该怎么办呢，我只想查询出来有关中国的内容啊，没关系中文分词帮你解决。

（2）ES配置中文分词

  常见的中文分词插件：IK，庖丁解牛中文分词等等。这里我们使用IK分词。
① 下载： https://github.com/medcl/elasticsearch-analysis-ik 版本对应
ElasticSearch的API(java/scala)
② 使用maven对源代码进行编译（在IK_HOME下）：(mvn clean install -DskipTests)
③ 把编译后的target/releases下的zip文件拷贝到 ES_HOME/plugins/analysis-ik目录下面，然后解压将其中的plugin-descriptor.properties 和plugin-security.policy文件中的ES的版本改为自己使用的版本
④ 修改ES_HOME/config/elasticsearch.yml文件，添加（ES6.x以上版本无需此操作）index.analysis.analyzer.default.type: ik
⑤ 重启es服务
这里小编就有些粗暴了：
#ps -aux|grep elasticsearch
#kill -9 pid
#/ES_HOME/bin/elasticsearch -d 启动

（3）重新测试

第一步： 将之前数据进行删除
curl -XDELETE ‘http://192.168.130.131:9200/chinese/1’
curl -XDELETE ‘http://192.168.130.131:9200/chinese/2’
curl -XDELETE ‘http://192.168.130.131:9200/chinese/3’
curl -XDELETE ‘http://192.168.130.131:9200/chinese/4’
第二步： 重新加载数据，并设置为IK分词
#设置为ik分词
curl -XPOST http://192.168.130.131:9200/chinese/fulltext/_mapping -H ‘Content-Type:application/json’ -d’
{
"properties": {
"content": {
"type": "text",
"analyzer": "ik_max_word",
"search_analyzer": "ik_max_word"
}
}
}’

    #添加数据
    curl -H "Content-Type: application/json" -XPOST http://192.168.130.131:9200/chinese/fulltext/1 -d'{"content":"美国留给伊拉克的是个烂摊子吗"}'
    curl -H "Content-Type: application/json" -XPOST http://192.168.130.131:9200/chinese/fulltext/2 -d'{"content":"公安部：各地校车将享最高路权"}'
    curl -H "Content-Type: application/json" -XPOST http://192.168.130.131:9200/chinese/fulltext/3 -d'{"content":"中韩渔警冲突调查：韩警平均每天扣1艘中国渔船"}'
    curl -H "Content-Type: application/json" -XPOST http://192.168.130.131:9200/chinese/fulltext/4 -d'{"content":"中国驻洛杉矶领事馆遭亚裔男子枪击 嫌犯已自首"}'

第三步：
重新执行刚刚上面的代码，这里我们看看结果：
ElasticSearch的API(java/scala)

6.Elasticsearch On Spark

整合条件：
ES官网：
https://www.elastic.co/guide/en/elasticsearch/hadoop/current/install.html
maven依赖：https://mvnrepository.com/artifact/org.elasticsearch/elasticsearch-hadoop/6.2.4

<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch-hadoop</artifactId>
    <version>6.2.4</version>
</dependency>
//如果使用spark中可以读到ES中的数据，需要导入隐式转换
import java.util.Date

import com.zy.es.utils.ElasticSearchUtil
import org.apache.spark.rdd.RDD
import org.apache.spark.{SparkConf, SparkContext}
import org.elasticsearch.cluster.metadata.MetaData.XContentContext
import org.elasticsearch.common.xcontent.XContentType
import org.elasticsearch.spark._

/**
  * spark整合ES
  * 通过spark去读取es中的数据，同时将操作之后的结果落地到ES
  */

object EsOnSpark {

  private val client = ElasticSearchUtil.getTransportClient()

  def main(args: Array[String]): Unit = {
    val conf = new SparkConf()
    conf.setAppName("EsOnSpark")
      .setMaster("local[2]")
      .set("es.index.auto.create", "true") //写数据的时候如果索引库不存在，自动创建
      .set("es.nodes", "192.168.130.131") //设置ES集群的节点
      .set("es.port", "9200") //设置ES集群的端口

    val sc = new SparkContext(conf)
    var EsRDD: RDD[(String, String)] = sc.esJsonRDD("library/books") //指定index/type
    var index = "es-spark"
    var `type` = "book"
    EsRDD.foreach { case (id, json) => {
      client.prepareIndex(index, `type`, new Date().getTime.toString)
        .setSource(json, XContentType.JSON).get()
      println(id + "" + json)
    }
    }
    sc.stop()
  }
}

这里只是小编介绍一些常见的API操作，大家知道ES最大的优势在于他的查询，后期小编会进一步的补充关于ElasticSearch强大的查询功能的API。

原创文章，作者：Maggie-Hunter，如若转载，请注明出处：https://blog.ytso.com/193292.html

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