elasticsearch（一）：JAVA api操作

1.创建一个mavan项目，项目的以来配置如下。

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.es</groupId>
    <artifactId>es-test</artifactId>
    <version>1.0-SNAPSHOT</version>


    <dependencies>

        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
            <version>6.3.2</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.21</version>
        </dependency>

        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.8.2</version>
        </dependency>

        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.0</version>
        </dependency>
    </dependencies>
</project>

2.建立连接elasticsearch的工具类。

package com.util;


import org.elasticsearch.client.Client;
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.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;

public class ESUtils {
    public static final String INDEX_NAME="userindex";

    public static String getIndexName(){
        return INDEX_NAME;
    }
    public static final String TYPE_NAME="tweet";

    public static String getTypeName(){
        return TYPE_NAME;
    }

    public static Client getClient(){
        Settings settings = Settings.builder()
                //指定集群名称
                .put("cluster.name","my-application")
                //探测集群中机器状态
                .put("client.transport.sniff",true).build();

        //创建客户端
        Client client = null;
        try {
            client = new PreBuiltTransportClient(settings).addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9300));
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        return client;
    }


    public static void  closeClient(Client client){
        if(null != client){
            client.close();
        }
    }
}

3.创建索引

 /**
     * 创建索引
     * 如果创建的索引名称已经存在，创建会抛出异常，因此先查询要创建的索引是否已存在，不存在在创建
     */
    @Test
    public void testCreate(){
        //待创建的索引名称
        String indexName = "userindex";
        //获取连接
        Client client = ESUtils.getClient();
        //判断索引是否存在
        IndicesExistsRequest existsRequest = new IndicesExistsRequest(indexName);
        IndicesExistsResponse existsResponse = client.admin().indices().exists(existsRequest).actionGet();
        if(!existsResponse.isExists()){
            //创建索引
            CreateIndexRequest createIndexRequest = new CreateIndexRequest(indexName);
            CreateIndexResponse createIndexResponse = client.admin().indices().create(createIndexRequest).actionGet();
            //判断创建是否成功
            if (createIndexResponse.isAcknowledged()){
                logger.info("创建成功");
            }else{
                logger.info("创建失败");
            }
        }else {
            logger.info("索引已存在，无法创建");
        }
        //关闭连接
        ESUtils.closeClient(client);
    }

4.向索引添加数据

/**
     * 向索引中逐条加入数据
     */
    @Test
    public void add(){
        //获取连接
        Client client = ESUtils.getClient();
        //待添加的json数据
        String strJson ="{"age":25,"name":"张三","weight":76,"married":true}";
        XContentParser parser = null;
        try {
            //数据解析，因为不支持json和对象类型的数据，要将其转为map
             parser = XContentFactory.xContent(XContentType.JSON).createParser(NamedXContentRegistry.EMPTY,DeprecationHandler.THROW_UNSUPPORTED_OPERATION,strJson);
             //插入数据
            IndexResponse indexResponse = client.prepareIndex().setIndex(ESUtils.getIndexName())
                    .setType(ESUtils.getTypeName())
                    .setSource(parser.map())
                    //设置数据的id，id唯一，如果id已存在则是修改
                    .setId("2")
                    .execute()
                    .actionGet();
            
            logger.info("添加成功，"+indexResponse.status());
 　　　　} catch (IOException e) { 
　　　　　　　　e.printStackTrace(); 
　　　　}finally { 
　　　　　　ESUtils.closeClient(client); 
　　} 
}

5.修改数据

  /**
     * 更新数据
     */
    @Test
    public void update(){
        Client client = ESUtils.getClient();
        Map<String,Object> map = new HashMap<String, Object>();
        map.put("age",56);
        map.put("name","李四");
        map.put("weight",69);
        map.put("married",false);
        UpdateResponse updateResponse = client.prepareUpdate()
                .setIndex(ESUtils.getIndexName())
                .setType(ESUtils.getTypeName())
                .setDoc(map)
                //要更新的数据的id
                .setId("2").execute().actionGet();

        logger.info("更新成功,"+updateResponse.status());
        ESUtils.closeClient(client);
    }

6.删除数据

/**
     * 根据id删除数据
     */
    @Test
    public void delete(){
        //获取连接
        Client client = ESUtils.getClient();
        //删除数据
        DeleteResponse deleteResponse = client.prepareDelete()
                .setIndex(ESUtils.getIndexName())
                .setType(ESUtils.getTypeName())
                //设置id
                .setId("1")
                .execute().actionGet();

        logger.info("删除成功,"+deleteResponse.status());
        //关闭连接
        ESUtils.closeClient(client);
    }

7.根据id查询数据

/**
     * 根据id查询数据
     */
    @Test
    public void select(){
        //获取连接
        Client client = ESUtils.getClient();
        //查询数据
        GetResponse getResponse = client.prepareGet()
                .setIndex(ESUtils.getIndexName())
                .setType(ESUtils.getTypeName())
                .setId("1")
                .execute().actionGet();
        //数据
        logger.info("data:="+getResponse.getSourceAsString());
        //关闭连接
        ESUtils.closeClient(client);
    }

8.全文查询

 /**
     * 全文检索数据
     */
    @Test
    public void search(){
        //获取连接
        Client client = ESUtils.getClient();
        //设置查询条件
        QueryBuilder queryBuilder = QueryBuilders.queryStringQuery("ipad");
        //查询
        SearchResponse response = client.prepareSearch(ESUtils.getIndexName())
                .setQuery(queryBuilder)
                //设置分页
                .setFrom(0).setSize(60)
                .execute().actionGet();
        //获取查询结果
        SearchHits shs = response.getHits();
        logger.info("查询数据条数:"+shs.getTotalHits());
        for (SearchHit hit:shs.getHits()) {
            logger.info(hit.getSourceAsString());
        }
        //关闭连接
        ESUtils.closeClient(client);
    }

9.批量插入数据

   //批量插入数据
    @Test
    public void testBulk(){
        //获取连接
        Client client = ESUtils.getClient();
        //批量接口
        BulkRequestBuilder bulkRequestBuilder = client.prepareBulk();
        User user = new User();
        //设置对象的属性
        for (int i=3;i<40002;i++){
            user.setName("user_"+UUID.randomUUID().toString().replace("-","").substring(0,6));
            SecureRandom random = new SecureRandom();
            long l = Math.abs(random.nextLong());
            user.setWeight(l);
            user.setMarried(l%3==0?true:false);
            user.setAge(l%2==0?28:82);
            //将对象转为json字符串
            Gson gson = new Gson();
            String json = gson.toJson(user);
            XContentParser parser = null;
            //数据转换
            try {
                parser = XContentFactory.xContent(XContentType.JSON).createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, json);
            } catch (IOException e) {
                e.printStackTrace();
            }
            IndexRequestBuilder ir = null;
            //预插入数据
            try {
                ir = client.prepareIndex("userindex","tweet",String.valueOf(i)).setSource(parser.map());
            } catch (IOException e) {
                e.printStackTrace();
            }
            bulkRequestBuilder.add(ir);
        }
       //批量插入
        BulkResponse bulkResponse  = bulkRequestBuilder.execute().actionGet();

        //判断插入是否失败
        if(bulkResponse.hasFailures()){
            //失败原因
            logger.info(bulkResponse.buildFailureMessage());
            logger.info("失败");
        }
    }

10.按指定条件查询

   /**
     * 按指定属性查询
     */
    @Test
    public void testSearchByFiled(){
        //获取连接
        Client client = ESUtils.getClient();
        //查询过滤器
        BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
        //查询条件  查询字段名称  和 值
        boolQueryBuilder.must(QueryBuilders.termQuery("age",28));
        boolQueryBuilder.must(QueryBuilders.termQuery("married",true));
        //知道要查询的索引和type
        SearchRequestBuilder searchRequestBuilder = client.prepareSearch(ESUtils.getIndexName()).setTypes(ESUtils.getTypeName());
        //设置查询的分页
        searchRequestBuilder.setQuery(boolQueryBuilder).setFrom(0).setSize(10000);
        //执行查询
        SearchResponse response = searchRequestBuilder.execute().actionGet();
        //查询结果数
        logger.info("数据总数:"+response.getHits().totalHits);
        //变量查询结果集
        for (SearchHit hit:response.getHits()) {
            logger.info(hit.getSourceAsString());
        }
        //关闭连接
        ESUtils.closeClient(client);
    }

11.聚合数据

  /**
     * 按指定条件聚合数据（分类统计）
     */
    @Test
    public void testFacets(){
        //获取连接
        Client client = ESUtils.getClient();
        //设置待查询的索引和类型
        SearchRequestBuilder searchRequestBuilder = client.prepareSearch(ESUtils
        .getIndexName()).setTypes(ESUtils.getTypeName());
        //设置查询条件
        TermsAggregationBuilder builder = AggregationBuilders
                //查询结果集名称
                .terms("marry")
                //要查询的属性名称
                .field("age");
        searchRequestBuilder.addAggregation(builder);
        //执行查询
        SearchResponse response = searchRequestBuilder.execute().actionGet();
        //根据设置的名字获取查询结果
        Terms terms = response.getAggregations().get("marry");
        List<? extends Terms.Bucket> buckets = terms.getBuckets();
        Map<String,String> map = new HashMap<String, String>();
        //聚合统计数量
        for (Terms.Bucket bucket :buckets){
            String key = bucket.getKeyAsString();
            map.put(key,bucket.getDocCount()+"");
        }
        //输出查询数量
        for (Map.Entry<String,String> entry : map.entrySet()){
            logger.info(entry.getKey()+":"+entry.getValue());
        }
        //关闭连接
        ESUtils.closeClient(client);
    }

12.删除索引

/**
     * 删除索引
     */
    @Test
    public void testDelete(){
        //获取连接
        Client client = ESUtils.getClient();
        //判断索引是否存在
        IndicesExistsRequest existsRequest = new IndicesExistsRequest(ESUtils.getIndexName());
        IndicesExistsResponse existsResponse = client.admin().indices().exists(existsRequest).actionGet();
        if(existsResponse.isExists()){
            //删除
            DeleteIndexResponse deleteIndexResponse = client.admin().indices().prepareDelete(ESUtils.getIndexName()).execute().actionGet();
            if(deleteIndexResponse.isAcknowledged()){
                logger.info("删除成功");
            }else{
                logger.info("删除失败");
            }
        }else {
            logger.info("索引 "+ESUtils.getIndexName()+" 不存在");
        }
        //关闭连接
        ESUtils.closeClient(client);
    }