Elasticsearch java api操作（二）（Java High Level Rest Client）

一、说明：

　　一、Elasticsearch提供了两个JAVA REST Client版本：

　　1、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Elasticsearch版本。

　　特点：maven引入

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

　　2、java high 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，使用的版本需要保存和ES服务一致的版本，否则会有版本问题。

　　从6.0.0开始加入的，目的是以java面向对象的方式进行请求、响应处理。

　　每个API支持 同步、异步 两种方式，同步方法之间返回一个结果对象。异步的方法以async为后缀，通过listener参数来通知结果。高级java resy客户端依赖Elasticsearch core pproject

　　兼容性说明：

　　依赖jdk1.8和Elasticsearch core project

二、Java Low Level Rest Client的使用

1、JAVA High Level Rest Client maven集成

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>6.3.1</version>
</dependency>

版本：

Elasticsearch 6.3.1

pom文件：

<dependencies>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>6.3.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.7</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.7</version>
        </dependency>

        <dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>0.9</version>
        </dependency>
    </dependencies>

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：

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

/**
 * @Author: xiaolaotou
 * @Date: 2019/4/28
 */
public class ClientUtil {
    public static RestHighLevelClient getClient(){
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("192.168.200.100",9200,"http"),
                        new HttpHost("192.168.200.101",9200,"http"),
                        new HttpHost("192.168.200.102",9200,"http"))
        );
        return client;
    }
}

2、创建索引

  /**
     * 创建索引
     * @throws Exception
     */
    public static void createindex()throws Exception{
        RestHighLevelClient client = ClientUtil.getClient();
        //1、创建索引，设置索引名
        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",1)//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、发送方式
//        //5、1采用同步方式发送请求
        CreateIndexResponse response = client.indices().create(request);
//        处理响应
        boolean acknowledged = response.isAcknowledged();
        boolean shardsAcknowledged = response.isShardsAcknowledged();
        System.out.println("acknowledged = " + acknowledged);
        System.out.println("shardsAcknowledged = " + shardsAcknowledged);
        client.close();
        //5、2采用异步方法发送请求
//        ActionListener<CreateIndexResponse> listener = new ActionListener<CreateIndexResponse>() {
//            @Override
//            public void onResponse(CreateIndexResponse createIndexResponse) {
//                //处理响应
//                boolean acknowledged = createIndexResponse.isAcknowledged();
//                boolean shardsAcknowledged = createIndexResponse.isShardsAcknowledged();
//                System.out.println("shardsAcknowledged = " + shardsAcknowledged);
//                System.out.println("acknowledged = " + acknowledged);
//            }
//            @Override
//            public void onFailure(Exception e) {
//                System.out.println("创建索引异常 = " + e.getMessage());
//            }
//        };
//        client.indices().createAsync(request,listener);
//        client.close();
    }

3、index document

  public static void indexDocument() throws IOException {
        RestHighLevelClient client = ClientUtil.getClient();
        //1、创建索引请求
        IndexRequest request = new IndexRequest("mess", "_doc");
        //2、准备文档数据
        //方式一：直接给JSON串
        String jsonString = "{" +
                "\"user\":\"kimchy\"," +
                "\"postDate\":\"2013-01-31\"," +
                "\"message\":\"trying out Elasticsearch\"" +
                "}";
        request.source(jsonString, XContentType.JSON);

        //方式二：以map对象来表示文档
//        HashMap<Object, Object> 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-->同步方式
        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);
        }
        //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);
                }
            }
        }
        client.close();

        //异步方式
//        ActionListener<IndexResponse> listener = new ActionListener<IndexResponse>(){
//            @Override
//            public void onResponse(IndexResponse indexResponse) {
//                //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。");
//                    }
//                }
//            }
//            @Override
//            public void onFailure(Exception e) {
//                System.out.println("创建索引异常：" + e.getMessage());
//            }
//        };
//        client.indexAsync(request,listener);
//        client.close();
    }

4、get document（获取文档数据）

/**
     * 获取文档数据
     * @throws IOException
     */
    public static void getDocument() throws IOException {
        RestHighLevelClient client = ClientUtil.getClient();
        //1、创建获取文档请求
        GetRequest request = new GetRequest("mess","_doc","bcUli2oBM0IXAkB-Yvpr");
        //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","postDate"};
        String[] excludes = Strings.EMPTY_ARRAY;
        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();*/
        //发送请求
        GetResponse getResponse = null;
        try {
            // 同步请求
            getResponse = client.get(request);
            System.out.println("getResponse = " + getResponse);
        } 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);
        } catch (IOException e) {
            e.printStackTrace();
        }
        //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<String, Object> 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" );
            }
        }
    client.close();

5、bulk批量索引

import org.apache.log4j.LogManager;
import org.apache.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;

import java.io.IOException;

/**
 * @Author: xiaolaotou
 * @Date: 2019/5/6
 */
public class BulkIndex {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = ClientUtil.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"));
        // 2、可选的设置
        /*
            request.timeout("2m");
            request.setRefreshPolicy("wait_for");
            request.waitForActiveShards(2);
        */
        //发送请求--》同步方式
        BulkResponse bulkResponse = client.bulk(request);
        //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
                }
            }
        }
        client.close();
    }
}

6、Search查询数据

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;

/**
 *
 * @author xiaolaotou
 * @date 2019/5/6
 *
 */
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<String, Object> sourceAsMap = hit.getSourceAsMap(); // 取成map对象
                //从map中取字段值
                /*
                String documentTitle = (String) sourceAsMap.get("title");
                List<Object> users = (List<Object>) sourceAsMap.get("user");
                Map<String, Object> innerObject = (Map<String, Object>) sourceAsMap.get("innerObject");
                */
                logger.info("index:" + index + "  type:" + type + "  id:" + id);
                logger.info(sourceAsString);

                //取高亮结果
                /*Map<String, HighlightField> highlightFields = hit.getHighlightFields();
                HighlightField highlight = highlightFields.get("title");
                Text[] fragments = highlight.fragments();
                String fragmentString = fragments[0].string();*/
            }

            // 获取聚合结果
            /*
            Aggregations aggregations = searchResponse.getAggregations();
            Terms byCompanyAggregation = aggregations.get("by_company");
            Bucket elasticBucket = byCompanyAggregation.getBucketByKey("Elastic");
            Avg averageAge = elasticBucket.getAggregations().get("average_age");
            double avg = averageAge.getValue();
            */

            // 获取建议结果
            /*Suggest suggest = searchResponse.getSuggest();
            TermSuggestion termSuggestion = suggest.getSuggestion("suggest_user");
            for (TermSuggestion.Entry entry : termSuggestion.getEntries()) {
                for (TermSuggestion.Entry.Option option : entry) {
                    String suggestText = option.getText().string();
                }
            }
            */

            //异步方式发送获查询请求
            /*
            ActionListener<SearchResponse> listener = new ActionListener<SearchResponse>() {
                @Override
                public void onResponse(SearchResponse getResponse) {
                    //结果获取
                }

                @Override
                public void onFailure(Exception e) {
                    //失败处理
                }
            };
            client.searchAsync(searchRequest, listener);
            */

        } catch (IOException e) {
            logger.error(e);
        }
    }
}

7、highlight 高亮

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.text.Text;
import org.elasticsearch.index.query.MatchQueryBuilder;
import org.elasticsearch.index.query.QueryBuilder;
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.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightField;
import java.io.IOException;
import java.util.Map;

/**
 * @Author: xiaolaotou

 * @Date: 2019/5/6
 */
public class highlight {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = ClientUtil.getClient();
        //1、创建请求
        SearchRequest searchRequest = new SearchRequest("mess");
        //2、用SearchSourceBuilder来构造查询请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        //构造QueryBuilder
        MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("user", "kimchy");
        sourceBuilder.query(matchQueryBuilder);
        //高亮设置
        HighlightBuilder highlightBuilder = new HighlightBuilder();
        //不同字段可有不同设置，如不同标签
         HighlightBuilder.Field highlightTitle = new HighlightBuilder.Field("user");
            highlightTitle.preTags("<strong>").postTags("</strong>");
            highlightBuilder.field(highlightTitle);
        sourceBuilder.highlighter(highlightBuilder);
        searchRequest.source(sourceBuilder);
        //3、发送请求
        SearchResponse searchResponse = client.search(searchRequest);
        //4、处理响应
        if (RestStatus.OK.equals(searchResponse.status())) {
            //处理搜索命中文档结果
            SearchHits hits = searchResponse.getHits();
            SearchHit[] searchHits = hits.getHits();
            for (SearchHit hit : searchHits) {
                //取_source字段值
                Map<String, Object> sourceAsMap = hit.getSourceAsMap(); // 取成map对象
                //从map中取字段值
                    /*String title = (String) sourceAsMap.get("title");
                    String content  = (String) sourceAsMap.get("content"); */
                System.out.println("sourceAsMap = " + sourceAsMap);
                //取高亮结果
                Map<String, HighlightField> highlightFields = hit.getHighlightFields();
                HighlightField highlight = highlightFields.get("user");
                if (highlight != null) {
                    Text[] fragments = highlight.fragments();  //多值的字段会有多个值
                    if (fragments != null) {
                        String fragmentString = fragments[0].string();
                        System.out.println("user highlight = " + fragmentString);
                        //可用高亮字符串替换上面sourceAsMap中的对应字段返回到上一级调用
                        //sourceAsMap.put("title", fragmentString);
                    }
                }
            }
        }
        client.close();
    }
}

8、查询建议

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.suggest.Suggest;
import org.elasticsearch.search.suggest.SuggestBuilder;
import org.elasticsearch.search.suggest.SuggestBuilders;
import org.elasticsearch.search.suggest.SuggestionBuilder;
import org.elasticsearch.search.suggest.completion.CompletionSuggestion;
import org.elasticsearch.search.suggest.term.TermSuggestion;
import org.elasticsearch.search.suggest.term.TermSuggestionBuilder;
import java.io.IOException;

/**
 * @Author: xiaolaotou
 * @Date: 2019/5/6
 */
public class SearchSuggestion {
    public static void termSuggest() throws IOException {
        RestHighLevelClient client = ClientUtil.getClient();
        //1、创建search请求
        SearchRequest searchRequest = new SearchRequest("mess");
        // 2、用SearchSourceBuilder来构造查询请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        //做查询建议
        //词项建议
        TermSuggestionBuilder termSuggestionBuilder = SuggestBuilders.termSuggestion("user").text("kimchy");
        SuggestBuilder suggestBuilder = new SuggestBuilder();
        suggestBuilder.addSuggestion("user",termSuggestionBuilder);
        sourceBuilder.suggest(suggestBuilder);

        //发送请求
        SearchResponse searchResponse = client.search(searchRequest);
        //处理响应
                //搜索结果状态信息
        if(RestStatus.OK.equals(searchResponse.status())) {
            // 获取建议结果
            Suggest suggest = searchResponse.getSuggest();
            TermSuggestion termSuggestion = suggest.getSuggestion("suggest_user");
            for (TermSuggestion.Entry entry : termSuggestion.getEntries()) {
                System.out.println("entry = " + entry.getText().string());
                for (TermSuggestion.Entry.Option option : entry) {
                    String suggestText = option.getText().string();
                    System.out.println("suggest option = " + suggestText);
                }
            }
        }
        }

    /**
     * 自动补全，根据用户的输入联想到可能的词或者短语
     */
    public static void completionSuggester() throws IOException {
        RestHighLevelClient client = ClientUtil.getClient();
        //1、创建请求
        SearchRequest searchRequest = new SearchRequest("mess");
        //2、用SearchSourceBuilder来构造查询请求体
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        SuggestionBuilder termSuggestionBuilder =
                SuggestBuilders.completionSuggestion("suggest").prefix("lucene s")
                        .skipDuplicates(true);
        SuggestBuilder suggestBuilder = new SuggestBuilder();
        suggestBuilder.addSuggestion("song-suggest", termSuggestionBuilder);
        sourceBuilder.suggest(suggestBuilder);

        searchRequest.source(sourceBuilder);

        //3、发送请求
        SearchResponse searchResponse = client.search(searchRequest);
        //4、处理响应
        //搜索结果状态信息
        if(RestStatus.OK.equals(searchResponse.status())) {
            // 获取建议结果
            Suggest suggest = searchResponse.getSuggest();
            CompletionSuggestion termSuggestion = suggest.getSuggestion("song-suggest");
            for (CompletionSuggestion.Entry entry : termSuggestion.getEntries()) {
                System.out.println("text: " + entry.getText().string());
                for (CompletionSuggestion.Entry.Option option : entry) {
                    String suggestText = option.getText().string();
                    System.out.println("suggest option  = " + suggestText);
                }
            }
        }

    }
    public static void main(String[] args) throws IOException {
        termSuggest();
//        completionSuggester();
    }
}

9、aggregation 聚合分析

import java.io.IOException;
import java.util.concurrent.ExecutionException;
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.client.RestHighLevelClient;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.Aggregations;
import org.elasticsearch.search.aggregations.BucketOrder;
import org.elasticsearch.search.aggregations.bucket.terms.Terms;
import org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket;
import org.elasticsearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
import org.elasticsearch.search.aggregations.metrics.avg.Avg;
import org.elasticsearch.search.builder.SearchSourceBuilder;

public class AggregationDemo {

    private static Logger logger = LogManager.getRootLogger();

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

            // 1、创建search请求
            //SearchRequest searchRequest = new SearchRequest();
            SearchRequest searchRequest = new SearchRequest("bank");

            // 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();

            sourceBuilder.size(0);

            //加入聚合
            //字段值项分组聚合
            TermsAggregationBuilder aggregation = AggregationBuilders.terms("by_age")
                    .field("age").order(BucketOrder.aggregation("average_balance", true));
            //计算每组的平均balance指标
            aggregation.subAggregation(AggregationBuilders.avg("average_balance")
                    .field("balance"));
            sourceBuilder.aggregation(aggregation);

            searchRequest.source(sourceBuilder);

            //3、发送请求
            SearchResponse searchResponse = client.search(searchRequest);

            //4、处理响应
            //搜索结果状态信息
            if(RestStatus.OK.equals(searchResponse.status())) {
                // 获取聚合结果
                Aggregations aggregations = searchResponse.getAggregations();
                Terms byAgeAggregation = aggregations.get("by_age");
                logger.info("aggregation by_age 结果");
                logger.info("docCountError: " + byAgeAggregation.getDocCountError());
                logger.info("sumOfOtherDocCounts: " + byAgeAggregation.getSumOfOtherDocCounts());
                logger.info("------------------------------------");
                for(Bucket buck : byAgeAggregation.getBuckets()) {
                    logger.info("key: " + buck.getKeyAsNumber());
                    logger.info("docCount: " + buck.getDocCount());
                    //logger.info("docCountError: " + buck.getDocCountError());
                    //取子聚合
                    Avg averageBalance = buck.getAggregations().get("average_balance");

                    logger.info("average_balance: " + averageBalance.getValue());
                    logger.info("------------------------------------");
                }
                //直接用key 来去分组
                /*Bucket elasticBucket = byCompanyAggregation.getBucketByKey("24");
                Avg averageAge = elasticBucket.getAggregations().get("average_age");
                double avg = averageAge.getValue();*/

            }

        } catch (Exception  e) {
            logger.error(e);
        }
    }
}