elastic客户端TransportClient的使用

　　关于TransportClient，elastic计划在Elasticsearch 7.0中弃用TransportClient，并在8.0中完全删除它。后面，应该使用Java高级REST客户端，它执行HTTP请求而不是序列化的Java请求。Java客户端主要用途有:

　　(1)在现有集群上执行标准索引，获取，删除和搜索操作

　　(2)在正在运行的集群上执行管理任务

　　获取Elasticsearch客户端最常用方法是创建连接到群集的TransportClient。

maven依赖

　　<dependency>
　　　　<groupId>org.elasticsearch.client</groupId>
　　　　<artifactId>transport</artifactId>
　　　　<version>6.4.3</version>
　　</dependency>

　　客户端必须具有与群集中的节点相同的主要版本（例如2.x或5.x）。客户端可以连接到具有不同次要版本（例如2.3.x）的群集，但可能不支持新功能。理想情况下，客户端应具有与群集相同的版本。此博客目前正在使用的版本是6.4.3。

获取TransportClient

　　TransportClient使用传输模块远程连接到Elasticsearch集群。它不加入集群，而只是获取一个或多个初始传输地址，并在每个操作上以循环方式与它们通信。

import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.cluster.node.DiscoveryNode;
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.UnknownHostException;

public class Elasticsearch {
    public static void main(String[] args) throws UnknownHostException {
       //on startup
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
                //继续添加其他地址
        //on shutdown
        client.close();
    }
}

　　如果出现：

　　说明需要配置日志

　　maven依赖

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.11.1</version>
</dependency>

然后再resources里面添加log4j2.properties，内容如下：

appender.console.type = Console
appender.console.name = console
appender.console.layout.type = PatternLayout

rootLogger.level = info
rootLogger.appenderRef.console.ref = console

　　如果出现"Exception in thread "main" java.lang.NoSuchMethodError: org.apache.logging.log4j.Logger.debug(Ljava/lang/String;Ljava/lang/Object;)", 则说明版本冲突，或者引的包是错的。

 　　请注意，如果使用集群名称不是默认的“elasticsearch”，则必须设置集群名称， 通过对Settings经行设置：

Settings settings = Settings.builder()
        .put("cluster.name", "myClusterName").build();
TransportClient client = new PreBuiltTransportClient(settings);
//Add transport addresses and do something with the client...

 　　如果开启嗅探功能，即自动检测集群内其他的节点和新加入的节点，不需要全部都是用addTransportAddress添加，设置如下：

Settings settings = Settings.builder()
        .put("client.transport.sniff", true).build();
TransportClient client = new PreBuiltTransportClient(settings);

　　

Document APIs

　　Single document APIs

　　(1)Index api

import com.fasterxml.jackson.core.JsonProcessingException;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class Elasticsearch {
    public static void main(String[] args) throws UnknownHostException, JsonProcessingException {
        //on startup
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
                //继续添加其他地址
        Map<String, Object> json = new HashMap<String, Object>();
        json.put("user", "kimchy");
        json.put("postDate", new Date());
        json.put("message", "trying out Elasticsearch");
　　　　　// index--twitter  type--_doc  id--1
        IndexResponse indexResponse = client.prepareIndex("twitter", "_doc", "1").setSource(json, XContentType.JSON).get();
        // Index name
        String _index = indexResponse.getIndex();
        // Type name
        String _type = indexResponse.getType();
        // Document ID (generated or not)
        String _id = indexResponse.getId();
        // Version (if it's the first time you index this document, you will get: 1)
        long _version = indexResponse.getVersion();
        // status has stored current instance statement.
        RestStatus status = indexResponse.status();
        //on shutdown
        client.close();
    }
}

　　实现了数据的插入

　　(2)GET API

　　get API允许根据其id从索引中获取类型化的JSON文档。以下示例从名为twitter的索引中获取JSON文档，该类型名为_doc`，id值为1：

import com.fasterxml.jackson.core.JsonProcessingException;
import org.elasticsearch.action.get.GetRequestBuilder;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class Elasticsearch {
    public static void main(String[] args) throws UnknownHostException, JsonProcessingException {
        //on startup
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
                //继续添加其他地址
 
        GetResponse documentFields = client.prepareGet("twitter", "_doc", "1").get();
        System.out.println(documentFields.getIndex());
        System.out.println(documentFields.getType());
        System.out.println(documentFields.getId());
        System.out.println(documentFields.getSourceAsString());
        //on shutdown
        client.close();
    }
}

输出结果:

　　(3)DELETE  API

import com.fasterxml.jackson.core.JsonProcessingException;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.get.GetRequestBuilder;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class Elasticsearch {
    public static void main(String[] args) throws UnknownHostException, JsonProcessingException {
        //on startup
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
                //继续添加其他地址

        DeleteResponse response = client.prepareDelete("twitter", "_doc", "1").get();
        System.out.println(response.toString());
        //on shutdown
        client.close();
    }
}

　　结果如下:

 　　(4)Delete By Query API

import com.fasterxml.jackson.core.JsonProcessingException;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.get.GetRequestBuilder;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.reindex.BulkByScrollResponse;
import org.elasticsearch.index.reindex.DeleteByQueryAction;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class Elasticsearch {
    public static void main(String[] args) throws UnknownHostException, JsonProcessingException {
        //on startup
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
                //继续添加其他地址

        BulkByScrollResponse response = DeleteByQueryAction.INSTANCE.newRequestBuilder(client)
                .filter(QueryBuilders.matchQuery("user", "kimchy"))
                .source("twitter")
                .get();
        long deleted = response.getDeleted();

        //on shutdown
        client.close();
    }
}

以刚才那条index->twitter为例，此api先查询出满足条件的所有index,然后调用getDeleted函数删除相关的数据。

 　　(5)Update API

　　可以使用prepareUpdate（）方法

import com.fasterxml.jackson.core.JsonProcessingException;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.get.GetRequestBuilder;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.reindex.BulkByScrollResponse;
import org.elasticsearch.index.reindex.DeleteByQueryAction;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;

public class Elasticsearch {
    public static void main(String[] args) throws IOException {
        //on startup
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
                //继续添加其他地址

        client.prepareUpdate("twitter", "_doc", "1")
                .setDoc(jsonBuilder()
                        .startObject()
                        .field("user", "chenmz")
                        .endObject())
                .get();
        //on shutdown
        client.close();
    }
}

用kibana查询后:

发现名字已经发生改变，更改成功。

　　Multi-document APIs

　　(1)Multi Get API

　　multi get API允许根据索引和id获取文档列表，往elastic中添加id为2的document，然后查询:

import com.fasterxml.jackson.core.JsonProcessingException;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.get.GetRequestBuilder;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.get.MultiGetItemResponse;
import org.elasticsearch.action.get.MultiGetResponse;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.reindex.BulkByScrollResponse;
import org.elasticsearch.index.reindex.DeleteByQueryAction;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;

public class Elasticsearch {
    public static void main(String[] args) throws IOException {
        //on startup
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
                //继续添加其他地址

        MultiGetResponse multiGetItemResponses = client.prepareMultiGet()
                .add("twitter", "_doc", "1", "2")
                .get();
        for (MultiGetItemResponse itemResponse : multiGetItemResponses) {
            GetResponse response = itemResponse.getResponse();
            if (response.isExists()) {
                String json = response.getSourceAsString();
                System.out.println(json);
            }
        }

        //on shutdown
        client.close();
    }
}

运行结果:

 　　(2)Bulk API

　　批量API允许在单个请求中索引和删除多个文档。以下演示增加多个索引。

import com.fasterxml.jackson.core.JsonProcessingException;
import org.elasticsearch.action.bulk.BulkRequestBuilder;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.get.GetRequestBuilder;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.get.MultiGetItemResponse;
import org.elasticsearch.action.get.MultiGetResponse;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.reindex.BulkByScrollResponse;
import org.elasticsearch.index.reindex.DeleteByQueryAction;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;

public class Elasticsearch {
    public static void main(String[] args) throws IOException {
        //on startup
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
                //继续添加其他地址

        BulkRequestBuilder bulkRequest = client.prepareBulk();
        bulkRequest.add(client.prepareIndex("twitter", "_doc", "3")
                .setSource(jsonBuilder()
                        .startObject()
                        .field("user", "zhangsan")
                        .field("postDate", new Date())
                        .field("message", "trying out Elasticsearch")
                        .endObject()
                )
        );

        bulkRequest.add(client.prepareIndex("twitter", "_doc", "4")
                .setSource(jsonBuilder()
                        .startObject()
                        .field("user", "lisi")
                        .field("postDate", new Date())
                        .field("message", "another post")
                        .endObject()
                )
        );

        BulkResponse bulkResponse = bulkRequest.get();
        if (bulkResponse.hasFailures()) {
            // process failures by iterating through each bulk response item
        }

        //on shutdown
        client.close();
    }
}

　　然后查询，得到如下的结果:

　　说明批量添加索引成功。

 　　(4)Reindex API

　　 可以提供查询以过滤应该从源索引到目标索引重新索引哪些文档。就是在已有的索引当中选择一些放到另一个索引之中。

import com.fasterxml.jackson.core.JsonProcessingException;
import org.elasticsearch.action.bulk.BulkRequestBuilder;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.get.GetRequestBuilder;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.get.MultiGetItemResponse;
import org.elasticsearch.action.get.MultiGetResponse;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.reindex.BulkByScrollResponse;
import org.elasticsearch.index.reindex.DeleteByQueryAction;
import org.elasticsearch.index.reindex.ReindexAction;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;

public class Elasticsearch {
    public static void main(String[] args) throws IOException {
        //on startup
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
                //继续添加其他地址

        BulkByScrollResponse response = ReindexAction.INSTANCE.newRequestBuilder(client).source("_all")
                .destination("target_index")
                .filter(QueryBuilders.matchQuery("user", "lisi")).get();
        System.out.println(response.toString());

        //on shutdown
        client.close();
    }
}

其中.source后面可以添加具体的索引.source("index1", "index2");等。

用Kibana查询结果如下:

　　生成一个target_index，下面多了一条user为lisi的document

ps:这边的主要面向Document APIs, 其实呢还有很多其他的api, elastic封装了很多的其他api也能达到同样的效果。