elasticsearch系列七：ES Java客户端-Elasticsearch Java client

一、ES Client 简介

1. ES是一个服务，采用C/S结构

 

2. 回顾 ES的架构

 

3. ES支持的客户端连接方式

3.1 REST API ，端口 9200

　　这种连接方式对应于架构图中的RESTful style API这一层，这种客户端的连接方式是RESTful风格的，使用http的方式进行连接

3.2 Transport 连接 端口 9300

      这种连接方式对应于架构图中的Transport这一层，这种客户端连接方式是直接连接ES的节点，使用TCP的方式进行连接

4. ES提供了多种编程语言客户端

 

官网可以了解详情：

https://www.elastic.co/guide/en/elasticsearch/client/index.html

二、Java REST Client介绍

1. ES提供了两个JAVA REST client 版本

Java Low Level REST Client: 低级别的REST客户端，通过http与集群交互，用户需自己编组请求JSON串，及解析响应JSON串。兼容所有ES版本。
Java High Level REST Client: 高级别的REST客户端，基于低级别的REST客户端，增加了编组请求JSON串、解析响应JSON串等相关api。使用的版本需要保持和ES服务端的版本一致，否则会有版本问题。

2. Java Low Level REST Client 说明

特点，maven 引入、使用介绍： https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-low.html

API doc ：https://artifacts.elastic.co/javadoc/org/elasticsearch/client/elasticsearch-rest-client/6.2.4/index.html.

3. Java High Level REST Client 说明

从6.0.0开始加入的，目的是以java面向对象的方式来进行请求、响应处理。
每个API 支持 同步/异步 两种方式，同步方法直接返回一个结果对象。异步的方法以async为后缀，通过listener参数来通知结果。
高级java REST 客户端依赖Elasticsearch core project

兼容性说明：

依赖 java1.8 和 Elasticsearch core project
请使用与服务端ES版本一致的客户端版本

4. Java High Level REST Client  maven 集成

    org.elasticsearch.client
    elasticsearch-rest-high-level-client
    6.2.4

5. Java High Level REST Client  初始化

RestHighLevelClient client = new RestHighLevelClient(
        RestClient.builder(
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http")));

给定集群的多个节点地址，将客户端负载均衡地向这个节点地址集发请求

Client 不再使用了，记得关闭它：

client.close();

 API及用法示例，请参考：

https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high-supported-apis.html

三、Java High Level REST Client  使用示例

准备：

编写示例之前首先在maven工程里面引入和ES服务端版本一样的Java客户端

    
        org.elasticsearch.client
        elasticsearch-rest-high-level-client
        6.2.4
     

给定集群的多个节点地址，将客户端负载均衡地向这个节点地址集发请求：

InitDemo.java

package com.study.es_hrset_client;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;

/**
 * 
 * @Description: 获取Java High Level REST Client客户端
 * @author lgs
 * @date 2018年6月23日
 *
 */
public class InitDemo {

    public static RestHighLevelClient getClient() {

        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));

        return client;
    }
}

注意使用ES的客户端时类比之前我们在Kibana进行的ES的相关操作，这样使用起来更加有效果

1. Create index 创建索引

CreateIndexDemo.java

package com.study.es_hrset_client;

import java.io.IOException;

import org.elasticsearch.action.admin.indices.alias.Alias;
import org.elasticsearch.action.admin.indices.create.CreateIndexRequest;
import org.elasticsearch.action.admin.indices.create.CreateIndexResponse;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.XContentType;

/**
 * 
 * @Description: 创建索引
 * @author lgs
 * @date 2018年6月23日
 *
 */
public class CreateIndexDemo {

    public static void main(String[] args) {
        try (RestHighLevelClient client = InitDemo.getClient();) {

            // 1、创建 创建索引request 参数：索引名mess
            CreateIndexRequest request = new CreateIndexRequest("mess");

            // 2、设置索引的settings
            request.settings(Settings.builder().put("index.number_of_shards", 3) // 分片数
                    .put("index.number_of_replicas", 2) // 副本数
                    .put("analysis.analyzer.default.tokenizer", "ik_smart") // 默认分词器
            );

            // 3、设置索引的mappings
            request.mapping("_doc",
                    "  {\n" +
                    "    \"_doc\": {\n" +
                    "      \"properties\": {\n" +
                    "        \"message\": {\n" +
                    "          \"type\": \"text\"\n" +
                    "        }\n" +
                    "      }\n" +
                    "    }\n" +
                    "  }",
                    XContentType.JSON);

            // 4、 设置索引的别名
            request.alias(new Alias("mmm"));

            // 5、 发送请求
            // 5.1 同步方式发送请求
            CreateIndexResponse createIndexResponse = client.indices()
                    .create(request);

            // 6、处理响应
            boolean acknowledged = createIndexResponse.isAcknowledged();
            boolean shardsAcknowledged = createIndexResponse
                    .isShardsAcknowledged();
            System.out.println("acknowledged = " + acknowledged);
            System.out.println("shardsAcknowledged = " + shardsAcknowledged);

            // 5.1 异步方式发送请求
            /*ActionListener listener = new ActionListener() {
                @Override
                public void onResponse(
                        CreateIndexResponse createIndexResponse) {
                    // 6、处理响应
                    boolean acknowledged = createIndexResponse.isAcknowledged();
                    boolean shardsAcknowledged = createIndexResponse
                            .isShardsAcknowledged();
                    System.out.println("acknowledged = " + acknowledged);
                    System.out.println(
                            "shardsAcknowledged = " + shardsAcknowledged);
                }

                @Override
                public void onFailure(Exception e) {
                    System.out.println("创建索引异常：" + e.getMessage());
                }
            };

            client.indices().createAsync(request, listener);
            */
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

 运行结果：

acknowledged = true
shardsAcknowledged = true

2. index  document

 索引文档，即往索引里面放入文档数据.类似于数据库里面向表里面插入一行数据，一行数据就是一个文档

 IndexDocumentDemo.java

package com.study.es_hrset_client;

import java.io.IOException;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.action.DocWriteResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.action.support.replication.ReplicationResponse;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.rest.RestStatus;

/**
 * 
 * @Description: 索引文档，即往索引里面放入文档数据.类似于数据库里面向表里面插入一行数据，一行数据就是一个文档
 * @author lgs
 * @date 2018年6月23日
 *
 */
public class IndexDocumentDemo {
    
    private static Logger logger = LogManager.getRootLogger();  

    public static void main(String[] args) {
        try (RestHighLevelClient client = InitDemo.getClient();) {
            // 1、创建索引请求
            IndexRequest request = new IndexRequest(
                    "mess",   //索引
                    "_doc",     // mapping type
                    "1");     //文档id  
            
            // 2、准备文档数据
            // 方式一：直接给JSON串
            String jsonString = "{" +
                    "\"user\":\"kimchy\"," +
                    "\"postDate\":\"2013-01-30\"," +
                    "\"message\":\"trying out Elasticsearch\"" +
                    "}";
            request.source(jsonString, XContentType.JSON); 
            
            // 方式二：以map对象来表示文档
            /*
            Map jsonMap = new HashMap<>();
            jsonMap.put("user", "kimchy");
            jsonMap.put("postDate", new Date());
            jsonMap.put("message", "trying out Elasticsearch");
            request.source(jsonMap); 
            */
            
            // 方式三：用XContentBuilder来构建文档
            /*
            XContentBuilder builder = XContentFactory.jsonBuilder();
            builder.startObject();
            {
                builder.field("user", "kimchy");
                builder.field("postDate", new Date());
                builder.field("message", "trying out Elasticsearch");
            }
            builder.endObject();
            request.source(builder); 
            */
            
            // 方式四：直接用key-value对给出
            /*
            request.source("user", "kimchy",
                            "postDate", new Date(),
                            "message", "trying out Elasticsearch");
            */
            
            //3、其他的一些可选设置
            /*
            request.routing("routing");  //设置routing值
            request.timeout(TimeValue.timeValueSeconds(1));  //设置主分片等待时长
            request.setRefreshPolicy("wait_for");  //设置重刷新策略
            request.version(2);  //设置版本号
            request.opType(DocWriteRequest.OpType.CREATE);  //操作类别  
            */
            
            //4、发送请求
            IndexResponse indexResponse = null;
            try {
                // 同步方式
                indexResponse = client.index(request);            
            } catch(ElasticsearchException e) {
                // 捕获，并处理异常
                //判断是否版本冲突、create但文档已存在冲突
                if (e.status() == RestStatus.CONFLICT) {
                    logger.error("冲突了，请在此写冲突处理逻辑！\n" + e.getDetailedMessage());
                }
                
                logger.error("索引异常", e);
            }
            
            //5、处理响应
            if(indexResponse != null) {
                String index = indexResponse.getIndex();
                String type = indexResponse.getType();
                String id = indexResponse.getId();
                long version = indexResponse.getVersion();
                if (indexResponse.getResult() == DocWriteResponse.Result.CREATED) {
                    System.out.println("新增文档成功，处理逻辑代码写到这里。");
                } else if (indexResponse.getResult() == DocWriteResponse.Result.UPDATED) {
                    System.out.println("修改文档成功，处理逻辑代码写到这里。");
                }
                // 分片处理信息
                ReplicationResponse.ShardInfo shardInfo = indexResponse.getShardInfo();
                if (shardInfo.getTotal() != shardInfo.getSuccessful()) {
                    
                }
                // 如果有分片副本失败，可以获得失败原因信息
                if (shardInfo.getFailed() > 0) {
                    for (ReplicationResponse.ShardInfo.Failure failure : shardInfo.getFailures()) {
                        String reason = failure.reason(); 
                        System.out.println("副本失败原因：" + reason);
                    }
                }
            }
            
            
            //异步方式发送索引请求
            /*ActionListener listener = new ActionListener() {
                @Override
                public void onResponse(IndexResponse indexResponse) {
                    
                }

                @Override
                public void onFailure(Exception e) {
                    
                }
            };
            client.indexAsync(request, listener);
            */
            
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

 运行结果：

新增文档成功，处理逻辑代码写到这里。

3. get  document

 获取文档数据

 GetDocumentDemo.java

package com.study.es_hrset_client;

import java.io.IOException;
import java.util.Map;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.action.get.GetRequest;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.Strings;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.search.fetch.subphase.FetchSourceContext;

/**
 * 
 * @Description: 获取文档数据
 * @author lgs
 * @date 2018年6月23日
 *
 */
public class GetDocumentDemo {
    
    private static Logger logger = LogManager.getRootLogger();  

    public static void main(String[] args) {
        try (RestHighLevelClient client = InitDemo.getClient();) {
            // 1、创建获取文档请求
            GetRequest request = new GetRequest(
                    "mess",   //索引
                    "_doc",     // mapping type
                    "1");     //文档id  
            
            // 2、可选的设置
            //request.routing("routing");
            //request.version(2);
            
            //request.fetchSourceContext(new FetchSourceContext(false)); //是否获取_source字段
            //选择返回的字段
            String[] includes = new String[]{"message", "*Date"};
            String[] excludes = Strings.EMPTY_ARRAY;
            FetchSourceContext fetchSourceContext = new FetchSourceContext(true, includes, excludes);
            request.fetchSourceContext(fetchSourceContext); 
            
            //也可写成这样
            /*String[] includes = Strings.EMPTY_ARRAY;
            String[] excludes = new String[]{"message"};
            FetchSourceContext fetchSourceContext = new FetchSourceContext(true, includes, excludes);
            request.fetchSourceContext(fetchSourceContext);*/
            
            
            // 取stored字段
            /*request.storedFields("message"); 
            GetResponse getResponse = client.get(request);
            String message = getResponse.getField("message").getValue();*/
            
            
            //3、发送请求        
            GetResponse getResponse = null;
            try {
                // 同步请求
                getResponse = client.get(request);
            } catch (ElasticsearchException e) {
                if (e.status() == RestStatus.NOT_FOUND) {
                    logger.error("没有找到该id的文档" );
                }
                if (e.status() == RestStatus.CONFLICT) {
                    logger.error("获取时版本冲突了，请在此写冲突处理逻辑！" );
                }
                logger.error("获取文档异常", e);
            }
            
            //4、处理响应
            if(getResponse != null) {
                String index = getResponse.getIndex();
                String type = getResponse.getType();
                String id = getResponse.getId();
                if (getResponse.isExists()) { // 文档存在
                    long version = getResponse.getVersion();
                    String sourceAsString = getResponse.getSourceAsString(); //结果取成 String       
                    Map sourceAsMap = getResponse.getSourceAsMap();  // 结果取成Map
                    byte[] sourceAsBytes = getResponse.getSourceAsBytes();    //结果取成字节数组
                    
                    logger.info("index:" + index + "  type:" + type + "  id:" + id);
                    logger.info(sourceAsString);
                    
                } else {
                    logger.error("没有找到该id的文档" );
                }
            }
            
            
            //异步方式发送获取文档请求
            /*
            ActionListener listener = new ActionListener() {
                @Override
                public void onResponse(GetResponse getResponse) {
                    
                }
            
                @Override
                public void onFailure(Exception e) {
                    
                }
            };
            client.getAsync(request, listener);
            */
            
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

 4. Bulk 

 批量索引文档，即批量往索引里面放入文档数据.类似于数据库里面批量向表里面插入多行数据，一行数据就是一个文档

 BulkDemo.java

package com.study.es_hrset_client;

import java.io.IOException;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.elasticsearch.action.DocWriteRequest;
import org.elasticsearch.action.DocWriteResponse;
import org.elasticsearch.action.bulk.BulkItemResponse;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.action.update.UpdateResponse;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;

/**
 * 
 * @Description: 批量索引文档，即批量往索引里面放入文档数据.类似于数据库里面批量向表里面插入多行数据，一行数据就是一个文档
 * @author lgs
 * @date 2018年6月23日
 *
 */
public class BulkDemo {
    
    private static Logger logger = LogManager.getRootLogger();  

    public static void main(String[] args) {
        try (RestHighLevelClient client = InitDemo.getClient();) {
            
            // 1、创建批量操作请求
            BulkRequest request = new BulkRequest(); 
            request.add(new IndexRequest("mess", "_doc", "1")  
                    .source(XContentType.JSON,"field", "foo"));
            request.add(new IndexRequest("mess", "_doc", "2")  
                    .source(XContentType.JSON,"field", "bar"));
            request.add(new IndexRequest("mess", "_doc", "3")  
                    .source(XContentType.JSON,"field", "baz"));
            
            /*
            request.add(new DeleteRequest("mess", "_doc", "3")); 
            request.add(new UpdateRequest("mess", "_doc", "2") 
                    .doc(XContentType.JSON,"other", "test"));
            request.add(new IndexRequest("mess", "_doc", "4")  
                    .source(XContentType.JSON,"field", "baz"));
            */
            
            // 2、可选的设置
            /*
            request.timeout("2m");
            request.setRefreshPolicy("wait_for");  
            request.waitForActiveShards(2);
            */
            
            
            //3、发送请求        
        
            // 同步请求
            BulkResponse bulkResponse = client.bulk(request);
            
            
            //4、处理响应
            if(bulkResponse != null) {
                for (BulkItemResponse bulkItemResponse : bulkResponse) { 
                    DocWriteResponse itemResponse = bulkItemResponse.getResponse(); 

                    if (bulkItemResponse.getOpType() == DocWriteRequest.OpType.INDEX
                            || bulkItemResponse.getOpType() == DocWriteRequest.OpType.CREATE) { 
                        IndexResponse indexResponse = (IndexResponse) itemResponse;
                        //TODO 新增成功的处理

                    } else if (bulkItemResponse.getOpType() == DocWriteRequest.OpType.UPDATE) { 
                        UpdateResponse updateResponse = (UpdateResponse) itemResponse;
                       //TODO 修改成功的处理

                    } else if (bulkItemResponse.getOpType() == DocWriteRequest.OpType.DELETE) { 
                        DeleteResponse deleteResponse = (DeleteResponse) itemResponse;
                        //TODO 删除成功的处理
                    }
                }
            }
            
            
            //异步方式发送批量操作请求
            /*
            ActionListener listener = new ActionListener() {
                @Override
                public void onResponse(BulkResponse bulkResponse) {
                    
                }
            
                @Override
                public void onFailure(Exception e) {
                    
                }
            };
            client.bulkAsync(request, listener);
            */
            
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

 5. search

 搜索数据

 SearchDemo.java

package com.study.es_hrset_client;

import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.action.search.ShardSearchFailure;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.suggest.Suggest;
import org.elasticsearch.search.suggest.term.TermSuggestion;

/**
 * 
 * @Description: 搜索数据
 * @author lgs
 * @date 2018年6月23日
 *
 */
public class SearchDemo {
    
    private static Logger logger = LogManager.getRootLogger();  

    public static void main(String[] args) {
        try (RestHighLevelClient client = InitDemo.getClient();) {
            
            // 1、创建search请求
            //SearchRequest searchRequest = new SearchRequest();
            SearchRequest searchRequest = new SearchRequest("bank"); 
            searchRequest.types("_doc");
            
            // 2、用SearchSourceBuilder来构造查询请求体 ,请仔细查看它的方法，构造各种查询的方法都在这。
            SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); 
            
            //构造QueryBuilder
            /*QueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("user", "kimchy")
                    .fuzziness(Fuzziness.AUTO)
                    .prefixLength(3)
                    .maxExpansions(10);
            sourceBuilder.query(matchQueryBuilder);*/
            
            sourceBuilder.query(QueryBuilders.termQuery("age", 24)); 
            sourceBuilder.from(0); 
            sourceBuilder.size(10); 
            sourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS)); 
            
            //是否返回_source字段
            //sourceBuilder.fetchSource(false);
            
            //设置返回哪些字段
            /*String[] includeFields = new String[] {"title", "user", "innerObject.*"};
            String[] excludeFields = new String[] {"_type"};
            sourceBuilder.fetchSource(includeFields, excludeFields);*/
            
            //指定排序
            //sourceBuilder.sort(new ScoreSortBuilder().order(SortOrder.DESC)); 
            //sourceBuilder.sort(new FieldSortBuilder("_uid").order(SortOrder.ASC));
            
            // 设置返回 profile 
            //sourceBuilder.profile(true);
            
            //将请求体加入到请求中
            searchRequest.source(sourceBuilder);
            
            // 可选的设置
            //searchRequest.routing("routing");
            
            // 高亮设置
            /*
            HighlightBuilder highlightBuilder = new HighlightBuilder(); 
            HighlightBuilder.Field highlightTitle =
                    new HighlightBuilder.Field("title"); 
            highlightTitle.highlighterType("unified");  
            highlightBuilder.field(highlightTitle);  
            HighlightBuilder.Field highlightUser = new HighlightBuilder.Field("user");
            highlightBuilder.field(highlightUser);
            sourceBuilder.highlighter(highlightBuilder);*/
            
            
            //加入聚合
            /*TermsAggregationBuilder aggregation = AggregationBuilders.terms("by_company")
                    .field("company.keyword");
            aggregation.subAggregation(AggregationBuilders.avg("average_age")
                    .field("age"));
            sourceBuilder.aggregation(aggregation);*/
            
            //做查询建议
            /*SuggestionBuilder termSuggestionBuilder =
                    SuggestBuilders.termSuggestion("user").text("kmichy"); 
                SuggestBuilder suggestBuilder = new SuggestBuilder();
                suggestBuilder.addSuggestion("suggest_user", termSuggestionBuilder); 
            sourceBuilder.suggest(suggestBuilder);*/
            
            //3、发送请求        
            SearchResponse searchResponse = client.search(searchRequest);
            
            
            //4、处理响应
            //搜索结果状态信息
            RestStatus status = searchResponse.status();
            TimeValue took = searchResponse.getTook();
            Boolean terminatedEarly = searchResponse.isTerminatedEarly();
            boolean timedOut = searchResponse.isTimedOut();
            
            //分片搜索情况
            int totalShards = searchResponse.getTotalShards();
            int successfulShards = searchResponse.getSuccessfulShards();
            int failedShards = searchResponse.getFailedShards();
            for (ShardSearchFailure failure : searchResponse.getShardFailures()) {
                // failures should be handled here
            }
            
            //处理搜索命中文档结果
            SearchHits hits = searchResponse.getHits();
            
            long totalHits = hits.getTotalHits();
            float maxScore = hits.getMaxScore();
            
            SearchHit[] searchHits = hits.getHits();
            for (SearchHit hit : searchHits) {
                // do something with the SearchHit
                
                String index = hit.getIndex();
                String type = hit.getType();
                String id = hit.getId();
                float score = hit.getScore();
                
                //取_source字段值
                String sourceAsString = hit.getSourceAsString(); //取成json串
                Map sourceAsMap = hit.getSourceAsMap(); // 取成map对象
                //从map中取字段值
                /*
                String documentTitle = (String) sourceAsMap.get("title"); 
                List