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ElasticSearch Java API入门

2019-08-26 06:05:30来源：博客园 阅读 ()

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ElasticSearch Java API入门

目录

  • 说明
  • maven
  • 日志准备
  • Client
    • Java High Level REST Client
      • 特点
      • 入门

说明

萌新第一次写博客，写得不好的地方见谅，没人看得懂的话也就自己需要的时候来参考一下了。
博客园的markdown和有道云笔记还是有区别的，有序列表不能接空格，支持的目录级数也不多。
本文基于elasticsearch-6.1.1版本，本文内容与elasticsearch java api官网一致

maven

elasticsearch需要的jar包：

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>transport</artifactId>
    <version>6.1.1</version>
</dependency>

log4j2需要的jar包：

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.9.1</version>
</dependency>

日志准备

src/resource/log4j2.properties

appender.console.type = Console
appender.console.name = console
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = [%d{ISO8601}][%-5p][%-25c] %marker%m%n

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

log4j2在类里面的使用

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
Logger log=LogManager.getLogger(ESServiceImpl.class);

也可以使用其他日志，详见使用其它日志

Client

elseaticSearch java有2种客户端：TransportClient和RestClient
TransportClient和RestClient区别
这里推荐使用RestClient,因为TransportClient在es后面的版本可能会被废弃，RestClien的官方API在这里，RestClient也分为Java High Level REST Client和Java Low Level REST Client，它们的区别：

Low Client很完善，支持RESTful
High Client基于Low Client,封装了常用的API，但是还是不够完善，需要增加API，对版本要求很高
从TransportClient迁徙的话，首选High Client，因为API接收参数和返回值和TransportClient是一样的

这里我们使用Java High Level REST Client

Java High Level REST Client

特点

??基于Java Low REST Client。它的主要目标是公开API特定的方法，接受请求对象作为参数并返回响应对象，以便客户端本身处理请求编组和响应非编组。
??客户端是向前兼容的，这意味着它支持与Elasticsearch的更高版本进行通信。比如6.0客户端能够与任何6.x Elasticsearch节点通信,所以升级先升级节点，再升级客户端(Client)。打个比方，HighClient客户端是6.2版本，节点6.2、6.3、6.4都有，现在要将他们都升级到6.4，先升级客户端的话，6.4的客户端可能不支持节点6.3版本的API

入门

需要jdk8+,配置maven仓库

<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>6.1.1</version>
</dependency>
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-client</artifactId>
    <version>6.1.1</version>
</dependency>
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>6.1.1</version>
</dependency>

可能无法解析客户端的Lucene依赖关系。

<repository>
    <id>elastic-lucene-snapshots</id>
    <name>Elastic Lucene Snapshots</name>
    <url>http://s3.amazonaws.com/download.elasticsearch.org/lucenesnapshots/00142c9</url>
    <releases><enabled>true</enabled></releases>
    <snapshots><enabled>false</enabled></snapshots>
</repository>

连接工具类ElasticSearchTools

//创建连接工具类
public class ElasticSearchTools {
    public static RestHighLevelClient client=null;
    public final static String HOST = "192.168.22.128"; //服务器部署
    public final static Integer PORT = 9201; //端口
    public static RestHighLevelClient  getClientConnection(){
    //client = new RestHighLevelClient(RestClient.builder(new HttpHost(HOST, 9200, "http"), new HttpHost(HOST, PORT, "http")));
        client = new RestHighLevelClient(
                RestClient.builder(new HttpHost(new HttpHost(HOST, PORT, "http"))));
        return client;
    }
    public static void closeClientConnection(RestHighLevelClient client) throws IOException {
        client.close();
    }
    //在工具类里面定义一个写日志的静态方法
    public static void logInfo(Logger log,String message) {
        if(log.isInfoEnabled()){
            log.info(message);
        }
    }
}

索引API

删除索引
public boolean deleteIndexAPI(String index)throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    DeleteIndexRequest request = new DeleteIndexRequest(index); 
    //删除超时时间,推荐使用前者，最好不要使用魔法变量，便于理解和维护
    request.timeout(TimeValue.timeValueMinutes(2));  //request.timeout("2m");
    //连接到主节点的时间
    request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); 
    // request.masterNodeTimeout("1m");
    //设置如何解析不可用的索引
    request.indicesOptions(IndicesOptions.lenientExpandOpen()); 
    //flag，用来查看结果、返回
    boolean acknowledged=false;
    //删除
    DeleteIndexResponse deleteIndexResponse;
    try {
        deleteIndexResponse = client.indices().deleteIndex(request);
        //是否所有节点都已删除该索引
        acknowledged = deleteIndexResponse.isAcknowledged(); 
    }catch (ElasticsearchException  e) {
        if (e.status() == RestStatus.NOT_FOUND) {
            ElasticSearchTools.logInfo(log, "Index "+index+" Not Found");
        }
    }catch (Exception e) {
        e.printStackTrace();
    }finally {
        //关闭客户端
        ElasticSearchTools.closeClientConnection(client);
    }
    return acknowledged;
}

如果执行时间较长，使用异步删除

client.indices().deleteIndexAsync(request, new ActionListener<DeleteIndexResponse>() {
    @Override
    public void onResponse(DeleteIndexResponse deleteIndexResponse) {
        boolean acknowledged = deleteIndexResponse.isAcknowledged();
        if(acknowledged) {
            ElasticSearchTools.logInfo(log, "Success delete Index:"+index);
        }else {
            ElasticSearchTools.logInfo(log, "Failed delete Index:"+index);
        }
    }

    @Override
    public void onFailure(Exception e) {
        if(e instanceof ElasticsearchException) {
            if (((ElasticsearchException) e).status() == RestStatus.NOT_FOUND) {
                ElasticSearchTools.logInfo(log, "Index "+index+" Not Found");
            }
        }
    }
});

单个文档API

创建文档API----INDEX
public void indexAPI(Elastic es)throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    IndexRequest request = new IndexRequest(es.get_index(),es.get_type(),es.get_id()).source(es.get_resource());
    //超时时间
    request.timeout(TimeValue.timeValueSeconds(1));
    //乐观锁版本控制,create操作不支持
    //request.version(2);
    //刷新策略
    request.setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL);
    //操作类型：create创建文档,index创建、更新都可以
    request.opType(DocWriteRequest.OpType.INDEX); 
    try {
        IndexResponse indexResponse = client.index(request);
        if(indexResponse.getResult()==DocWriteResponse.Result.CREATED) {
            //识别本次的操作是create
            ElasticSearchTools.logInfo(log, 
                    "create document:"+indexResponse.getId()+",and now_version is :"+indexResponse.getVersion());
        }else if(indexResponse.getResult()==DocWriteResponse.Result.UPDATED) {
            //识别本次的操作是update
            ElasticSearchTools.logInfo(log, 
                    "update document:"+indexResponse.getId()+",and now_version is :"+indexResponse.getVersion());
        }
        ReplicationResponse.ShardInfo shards = indexResponse.getShardInfo();
        if (shards.getTotal() != shards.getSuccessful()) {
            ElasticSearchTools.logInfo(log,"分片备份不完全");
        }
    } catch (ElasticsearchException  e) {
        //冲突异常，操作时version与服务器不一致
        //create一个已有文档时
        if(e.status() == RestStatus.CONFLICT) {
            ElasticSearchTools.logInfo(log,"操作冲突！！！！！");
        }
    }catch (Exception e) {
        e.printStackTrace();
    }finally {
        ElasticSearchTools.closeClientConnection(client);
    }
}

注意：index操作有更新的功能，但是这里的更新是全部更新，不是匹配到的字段才更新，是一个完全替代的效果，相当于把原来的删除了，再去创建一个。同样有异步操作，和上面delete类似
结果测试

update document:2,and now_version is :3

根据id查找文档--GET

1.文档特定存储字段的搜索，像下面age这种设置了store:true的字段

{
  "mappings": {
    "doc":{
      "properties": {
        "name":{
          "type": "text"
        },
        "age":{
          "type": "integer",
          "store": true
        },
        "address":{
          "type": "text",
          "fields": {
            "keyword":{
              "type": "keyword"
            }
          }
        }
      }
    }
  }
public String getIndexAPI(Elastic es)throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    GetRequest request = new GetRequest(es.get_index(), es.get_type(), es.get_id());
    //在检索文档之前执行刷新,默认false
    request.refresh(true);
    //要查找文档的存储字段
    request.storedFields("age"); 
    GetResponse getResponse = null;
    try {
        getResponse = client.get(request);
        ElasticSearchTools.logInfo(log,getResponse.toString());
    }catch (ElasticsearchException e) {
        if (e.status() == RestStatus.NOT_FOUND) {
            ElasticSearchTools.logInfo(log,"Index Not Found");
        }
    }catch (Exception e) {
        e.printStackTrace();
    }finally {
        ElasticSearchTools.closeClientConnection(client);
    }
    ElasticSearchTools.logInfo(log,getResponse.getFields().toString());
    return null;
}

这样搜索出来只能显示查找结果和指定的存储字段属性，其它属性不能显示

{"_index":"zhangsun","_type":"doc","_id":"2","_version":1,"found":true,"fields":{"age":[22]}}
{age=DocumentField{name='age', values=[22]}}

2.还有一种方法就是使用FetchSourceContext查找

public String getIndexAPI(Elastic es) throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    GetRequest request = new GetRequest(es.get_index(), es.get_type(), es.get_id());
    //要查找的文档字段，支持匹配
     String[] includes = new String[]{"name", "*ress"};
     String[] excludes = Strings.EMPTY_ARRAY;
     //true和false表示是否查询_source里面的字段，includes/excludes表示为true时查询/不查询的字段
     FetchSourceContext fetchSourceContext = new FetchSourceContext(true,includes, excludes);
     request.fetchSourceContext(fetchSourceContext);
    // 在检索文档之前执行刷新,默认false
    request.refresh(true);
    //指定版本号才能查询,否则报错RestStatus.CONFLICT
    //request.version(1);
    GetResponse getResponse = null;
    String sourceAsString = null;
    try {
        getResponse = client.get(request);
        if(getResponse.isExists()) {
             ElasticSearchTools.logInfo(log,getResponse.toString());
             //将查询的_source里面的字段转化为json字符串，上面设置了false的话会出现NPE
             sourceAsString = getResponse.getSourceAsString();
             ElasticSearchTools.logInfo(log,sourceAsString);
            //将查询的_source里面的字段转化为map，上面设置了false的话会出现NPE
             Map<String, Object> sourceAsMap = getResponse.getSourceAsMap();
             ElasticSearchTools.logInfo(log,sourceAsMap.toString());
        }
    } catch (ElasticsearchException e) {
        if (e.status() == RestStatus.NOT_FOUND) {
            ElasticSearchTools.logInfo(log, "Index Not Found");
        }else if (e.status() == RestStatus.CONFLICT) {
            ElasticSearchTools.logInfo(log, "Version Not Match");
        }
        e.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    }finally {
        ElasticSearchTools.closeClientConnection(client);
    }
    return null;
    }

正常查询结果：

{"_index":"zhangsun","_type":"doc","_id":"2","_version":2,"found":true,"_source":{"address":"zhans guh hahaha jks dhjfs","name":"hjl"}}
{"address":"zhans guh hahaha jks dhjfs","name":"hjl"}
{address=zhans guh hahaha jks dhjfs, name=hjl}

==查找也有异步操作方法，原理同上==

删除文档--DELETE
public String deleteDocumentAPI(Elastic es) throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    DeleteRequest request = new DeleteRequest(es.get_index(), es.get_type(), es.get_id());
    request.timeout(TimeValue.timeValueMinutes(2)); 
    //刷新策略
    request.setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL); 
    //request.version(2); 
    try {
        DeleteResponse deleteResponse = client.delete(request);
        ElasticSearchTools.logInfo(log, deleteResponse.toString());
        //没找到文档不会报错，会将result的值设为not_found
        if (deleteResponse.getResult() == DocWriteResponse.Result.NOT_FOUND) {
            ElasticSearchTools.logInfo(log, "Document Not Found");
        }
        //分片信息
        ReplicationResponse.ShardInfo shardInfo = deleteResponse.getShardInfo();
        //处理成功分片数小于总分片数的情况
        if (shardInfo.getTotal() != shardInfo.getSuccessful()) {
            ElasticSearchTools.logInfo(log, "Shards Error");
        }
        //处理分片的失败
        if (shardInfo.getFailed() > 0) {
            for (ReplicationResponse.ShardInfo.Failure failure : shardInfo.getFailures()) {
                String reason = failure.reason(); 
                ElasticSearchTools.logInfo(log, "Shards Error"+reason);
            }
        }
    } catch (ElasticsearchException  e) {
        //同样删除时版本问题
        if (e.status() == RestStatus.CONFLICT) {
            ElasticSearchTools.logInfo(log, "Version Not Match");
        }
        e.printStackTrace();
    }finally {
        ElasticSearchTools.closeClientConnection(client);
    }
    return null;
}

测试结果(出现Shards Error的原因是因为我只启动了集群中的一个ES实例，Index的primary shards在本节点上，而replica shard始终是UNASSIGNED，这是集群健康状态也是yellow)

DeleteResponse[index=zhangsun,type=doc,id=2,version=3,result=deleted,shards=ShardInfo{total=2, successful=1, failures=[]}]
Shards Error

更新文档--UPDATE

1.使用脚本script方式更新：

public String updateDocumentAPI(Elastic es) throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    UpdateRequest request = new UpdateRequest(es.get_index(), es.get_type(), es.get_id());
    request.retryOnConflict(3); //多用户在同时更新的时候会造成冲突，设置重试次数
    request.timeout(TimeValue.timeValueSeconds(1)); 
    request.setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL); 
    //request.version(2); 不能和request.retryOnConflict共存
    //设置一个key和value都是final的Map
    Map<String, Object> parameters = Collections.singletonMap("count", 4); 
    request.script(inline);  
    try {
        UpdateResponse updateResponse = client.update(request);
        if (updateResponse.getResult() == DocWriteResponse.Result.CREATED) {
            ElasticSearchTools.logInfo(log, "Document create operation");
        } else if (updateResponse.getResult() == DocWriteResponse.Result.UPDATED) {
            ElasticSearchTools.logInfo(log, "Document update operation");
        }else if (updateResponse.getResult() == DocWriteResponse.Result.NOOP) {
            ElasticSearchTools.logInfo(log, "The Same as Last Version,Nothing Done");
        }
        //分片状态判断这里就不写了，和前面一样
    } catch (ElasticsearchException  e) {
        if (e.status() == RestStatus.NOT_FOUND) {
            ElasticSearchTools.logInfo(log, "Document Not Found");
        }
        if (e.status() == RestStatus.CONFLICT) {
            ElasticSearchTools.logInfo(log, "Version Not Match");
        }
        e.printStackTrace();
    }catch (Exception e) {
        e.printStackTrace();
    }finally {
        ElasticSearchTools.closeClientConnection(client);
    }
    return null;
}

这段脚本的功能相当于:(==inline==在es6.x已经废弃了，使用source替代)

POST /zhangsun/doc/2/_update
{
  "script": {
    "inline": "ctx._source.age += params.count",
    "params": {
      "count":4
    }
  }
}

2.使用doc方式更新

public String updateDocumentAPI(Elastic es) throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    UpdateRequest request = new UpdateRequest(es.get_index(), es.get_type(), es.get_id());
    request.retryOnConflict(3); //多用户在同时更新的时候会造成冲突，设置重试次数
    request.timeout(TimeValue.timeValueSeconds(1)); 
    request.setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL); 
    //request.version(2); 不能和request.retryOnConflict共存
    request.doc(es.get_resource());//内容就是下面这个param，更多数据形式参考官网
    //Map<String,Object> param=new HashMap<String, Object>();
    //param.put("name", "zhansgun");
    //param.put("address", "China SiChaun");
    
    //让doc操作更新时，没有文档时可以创建一个
    request.docAsUpsert(true); 
    
    try {
        UpdateResponse updateResponse = client.update(request);
        ElasticSearchTools.logInfo(log, updateResponse.toString());
        if (updateResponse.getResult() == DocWriteResponse.Result.CREATED) {
            ElasticSearchTools.logInfo(log, "Document create operation");
        } else if (updateResponse.getResult() == DocWriteResponse.Result.UPDATED) {
            ElasticSearchTools.logInfo(log, "Document update operation");
        }else if (updateResponse.getResult() == DocWriteResponse.Result.NOOP) {
            ElasticSearchTools.logInfo(log, "The Same as Last Version,Nothing Done");
        }
        //分片状态判断这里就不写了，和前面一样
    } catch (ElasticsearchException  e) {
        if (e.status() == RestStatus.NOT_FOUND) {
            ElasticSearchTools.logInfo(log, "Document Not Found");
        }
        if (e.status() == RestStatus.CONFLICT) {
            ElasticSearchTools.logInfo(log, "Version Not Match");
        }
        e.printStackTrace();
    }catch (Exception e) {
        e.printStackTrace();
    }finally {
        ElasticSearchTools.closeClientConnection(client);
    }
    return null;
}

异步++

多个文档API

bulk批量操作
public String bulkAPI(Elastic es) throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    BulkRequest request = new BulkRequest();
    //删除id=1
    request.add(new DeleteRequest(es.get_index(), es.get_type(), "1")); 
    //局部更新id=2
    request.add(new UpdateRequest(es.get_index(), es.get_type(), "2") 
        .doc(XContentType.JSON,"address", "NanChong","name", "hahhahahha"));
    //创建id=4，存在则先删除再创建，完全替代
    request.add(new IndexRequest(es.get_index(), es.get_type(), "4")  
        .source(XContentType.JSON,"field", "baz"));
    request.timeout(TimeValue.timeValueMinutes(2)); 
    request.setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL); 
    request.waitForActiveShards(ActiveShardCount.ALL); 
    try {
    BulkResponse bulkResponse = client.bulk(request);
    //输出每个操作的结果
    for (BulkItemResponse bulkItemResponse : bulkResponse) {
        DocWriteResponse itemResponse = bulkItemResponse.getResponse(); 
        if (bulkItemResponse.getOpType() == DocWriteRequest.OpType.INDEX
                || bulkItemResponse.getOpType() == DocWriteRequest.OpType.CREATE) { 
            IndexResponse indexResponse = (IndexResponse) itemResponse;
            ElasticSearchTools.logInfo(log, "The Operation is Index,And the Result is:"+indexResponse.toString());
        } else if (bulkItemResponse.getOpType() == DocWriteRequest.OpType.UPDATE) { 
            UpdateResponse updateResponse = (UpdateResponse) itemResponse;
            ElasticSearchTools.logInfo(log, "The Operation is Update,And the Result is:"+updateResponse.toString());
        } else if (bulkItemResponse.getOpType() == DocWriteRequest.OpType.DELETE) { 
            DeleteResponse deleteResponse = (DeleteResponse) itemResponse;
            ElasticSearchTools.logInfo(log, "The Operation is Delete,And the Result is:"+deleteResponse.toString());
        }
    }
    //判断批操作是否有错误
    if (bulkResponse.hasFailures()) { 
        ElasticSearchTools.logInfo(log,"There are At Least One Error Occured:");
        for (BulkItemResponse bulkItemResponse : bulkResponse) {
            if (bulkItemResponse.isFailed()) { 
                BulkItemResponse.Failure failure = bulkItemResponse.getFailure(); 
                ElasticSearchTools.logInfo(log,failure.toString());
            }
        }
    }
    //分片状态判断这里就不写了，和前面一样
    } catch (ElasticsearchException  e) {
    if (e.status() == RestStatus.NOT_FOUND) {
        ElasticSearchTools.logInfo(log, "Document Not Found");
    }
        e.printStackTrace();
    }catch (Exception e) {
        e.printStackTrace();
    }finally {
        ElasticSearchTools.closeClientConnection(client);
    }
    return null;
}

The Operation is Delete,And the Result is:DeleteResponse[index=zhangsun,type=doc,id=1,version=2,result=deleted,shards=xxx]
The Operation is Update,And the Result is:UpdateResponse[index=zhangsun,type=doc,id=2,version=17,seqNo=27,primaryTerm=1,result=updated,shards=xxx]
The Operation is Update,And the Result is:UpdateResponse[index=zhangsun,type=doc,id=2,version=18,seqNo=28,primaryTerm=1,result=updated,shards=xxx]
The Operation is Index,And the Result is:IndexResponse[index=zhangsun,type=doc,id=4,version=1,result=created,seqNo=29,primaryTerm=1,shards=xxx]

bulk的API还配置有监听器BulkProcessor.Listener处理每个操作执行前后需要处理的内容

同样，异步操作++

查找API

searchAPI

1.普通匹配查询

public String searchAPI(Elastic es) throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    SearchRequest searchRequest = new SearchRequest(es.get_index()).types(es.get_type());
    searchRequest.preference("_local"); 
    
    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    //查找全部
    searchSourceBuilder.query(QueryBuilders.matchAllQuery());
    //精准匹配,使用keyword格式，因为text格式会分词
    //searchSourceBuilder.query(QueryBuilders.termQuery("address.keyword", "sichuan nanchong"));
    //模糊匹配，空格表示或
    //searchSourceBuilder.query(QueryBuilders.matchQuery("address", "sichaun nanchong"));
    //匹配短语
    //searchSourceBuilder.query(QueryBuilders.matchPhraseQuery("address", "sichuan nanchong"));
    searchSourceBuilder.from(0); 
    searchSourceBuilder.size(5); 
    searchSourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS));
    //结果排序
    searchSourceBuilder.sort(new ScoreSortBuilder().order(SortOrder.DESC));//按照score降序排序
    searchSourceBuilder.sort(new FieldSortBuilder("age").order(SortOrder.ASC));
    
    //开启搜索_source里面的内容
    searchSourceBuilder.fetchSource(true);
    //需要过滤的属性
    String[] includeFields = new String[] {"name", "address"};
    String[] excludeFields = new String[] {"age"};
    searchSourceBuilder.fetchSource(includeFields, excludeFields);
    
    //关联SearchSourceBuilder
    searchRequest.source(searchSourceBuilder);
    
    //搜索
    SearchResponse searchResponse;
    try {
        searchResponse = client.search(searchRequest);
        //状态结果
        RestStatus status = searchResponse.status();
        TimeValue took = searchResponse.getTook();
        Boolean terminatedEarly = searchResponse.isTerminatedEarly();
        boolean timedOut = searchResponse.isTimedOut();
        ElasticSearchTools.logInfo(log, "状态码:"+status.toString()+"花费时间:"+took+"请求提前终止:"+terminatedEarly+"超时:"+timedOut);
        //分片情况
        //int totalShards = searchResponse.getTotalShards();
        //int successfulShards = searchResponse.getSuccessfulShards();
        //int failedShards = searchResponse.getFailedShards();
        //for (ShardSearchFailure failure : searchResponse.getShardFailures()) {
            // failures should be handled here
        //}
        //数据结果
        SearchHits hits = searchResponse.getHits();
        long totalHits = hits.getTotalHits();
        float maxScore = hits.getMaxScore();
        ElasticSearchTools.logInfo(log, "查到结果数:"+totalHits+"最高得分:"+maxScore);
        SearchHit[] searchHits = hits.getHits();
        for (SearchHit hit : searchHits) {
            float score = hit.getScore();
            String sourceAsString = hit.getSourceAsString();
            //Map<String, Object> sourceAsMap = hit.getSourceAsMap();
            ElasticSearchTools.logInfo(log, "分数:"+score+"结果:"+sourceAsString);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }finally {
        ElasticSearchTools.closeClientConnection(client);
    }
    
    return null;
}

2.聚合

为了方便理解，现在kibana里面写一个实例

GET /zhangsun/_search
{
  "size": 0, //不显示查到的数据，只显示聚合结果
  "aggs": {
    "by_name": {
      "terms": {
        "field": "name.keyword",
        "size": 10
      },
      "aggs": {
        "avr_age": {
          "terms": {
            "field": "age",
            "size": 10
          }
        }
      }
    }
  }
}

运行结果:

{
  "took": 19,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 5,
    "max_score": 0,
    "hits": []
  },
  "aggregations": {
    "by_name": {
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": [
        {
          "key": "hjl",
          "doc_count": 3,
          "avr_age": {
            "doc_count_error_upper_bound": 0,
            "sum_other_doc_count": 0,
            "buckets": [
              {
                "key": 21,
                "doc_count": 1
              },
              {
                "key": 22,
                "doc_count": 1
              },
              {
                "key": 25,
                "doc_count": 1
              }
            ]
          }
        },
        {
          "key": "zhangsun",
          "doc_count": 2,
          "avr_age": {
            "doc_count_error_upper_bound": 0,
            "sum_other_doc_count": 0,
            "buckets": [
              {
                "key": 23,
                "doc_count": 1
              },
              {
                "key": 24,
                "doc_count": 1
              }
            ]
          }
        }
      ]
    }
  }
}

编写java代码

public String searchAPI(Elastic es) throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    SearchRequest searchRequest = new SearchRequest(es.get_index()).types(es.get_type());
    searchRequest.preference("_local"); 
    
    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    
    //聚合查询
    //按照name分组，并求个数和，再显示出前5条,聚合不能使用text类型的属性
    TermsAggregationBuilder aggregation = AggregationBuilders.terms("by_name").field("name.keyword").size(10);
    //在上面的基础上再在每条记录后面追加一个属性average_age显示年龄平均值
    aggregation.subAggregation(AggregationBuilders.avg("average_age").field("age"));
    searchSourceBuilder.aggregation(aggregation);
    
    //关联SearchSourceBuilder
    searchRequest.source(searchSourceBuilder);
    
    //搜索
    SearchResponse searchResponse;
    try {
        searchResponse = client.search(searchRequest);
        //状态结果
        RestStatus status = searchResponse.status();
        TimeValue took = searchResponse.getTook();
        Boolean terminatedEarly = searchResponse.isTerminatedEarly();
        boolean timedOut = searchResponse.isTimedOut();
        ElasticSearchTools.logInfo(log, "状态码:"+status.toString()+"花费时间:"+took+"请求提前终止:"+terminatedEarly+"超时:"+timedOut);
        //数据结果
        SearchHits hits = searchResponse.getHits();
        long totalHits = hits.getTotalHits();
        float maxScore = hits.getMaxScore();
        ElasticSearchTools.logInfo(log, "查到结果数:"+totalHits+"最高得分:"+maxScore);
        //获取聚合结果
        Aggregations aggregations = searchResponse.getAggregations();
        //获取by_name聚合对应结果
        Terms companyAggregation = (Terms) aggregations.get("by_name");
        //对应上面bucket，有多条记录
        List<? extends Bucket> buckets = companyAggregation.getBuckets();
        for (Bucket bucket : buckets) {
            String name = bucket.getKey().toString();
            long count = bucket.getDocCount();
            Avg averageAge=bucket.getAggregations().get("average_age");
            double avg = averageAge.getValue();
            ElasticSearchTools.logInfo(log,"name:"+name+",count:"+count+",avg_age:"+ String.valueOf(avg));
        }
    } catch (Exception e) {
        e.printStackTrace();
    }finally {
        ElasticSearchTools.closeClientConnection(client);
    }
    
    return null;
}

在聚合查询的时候也可以通过searchSourceBuilder.query()先过滤再聚合。

异步++

3.scrollSerachAPI

在查询的结果数据量特别大的时候，我们需要分页显示数据，虽然from..size可以实现分页效果，但是也仅仅是显示一页。当我们需要所有结果时则使用scroll

首先下载官网提供的有11w条数据的json数据https://download.elastic.co/demos/kibana/gettingstarted/shakespeare_6.0.json。
然后通过指令：curl -X POST "localhost:9200/_bulk?pretty&refresh" -H "Content-Type: application/json" --data-binary "@json文件位置"将它创建。

首先我们通过kibana先看一下效果

POST /shakespeare/doc/_search?scroll=1m
    {
      "query": { "match_all": {}},
      "_source": ["line_id","speaker"], 
      "size":10000,
      "sort": ["line_id"]
    }

控制台会打印前10000条数据，并且产生一个_scroll_id，将它复制到下面的_scroll_id字段里面

GET /_search/scroll
{
    "scroll": "1m", 
    "scroll_id" : _scroll_id
}

多次执行这段DSL语句，会分别打印后面1w-2w、2w-3w的数据。因为数据是11w+条，在第13次执行时就会没有数据了。

下面介绍怎么使用JavaAPI操作scroll

public String scrollSearchAPI(Elastic es) throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    //初始化，得到第一页数据以及scrollId
    SearchRequest searchRequest = new SearchRequest("shakespeare");
    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    searchSourceBuilder.query(QueryBuilders.matchAllQuery());
    searchSourceBuilder.size(5000); 
    searchRequest.source(searchSourceBuilder);
    //设置scroll
    searchRequest.scroll(TimeValue.timeValueMinutes(1L)); 
    SearchResponse searchResponse = client.search(searchRequest);
    //获取scrollId
    String scrollId = searchResponse.getScrollId(); 
    SearchHit[] searchHits = searchResponse.getHits().getHits(); 
    //根据scrollId找到后面的文档
    while(searchHits != null && searchHits.length > 0) {
        SearchScrollRequest scrollRequest = new SearchScrollRequest(scrollId); 
        scrollRequest.scroll(TimeValue.timeValueSeconds(30));
        SearchResponse searchScrollResponse = client.searchScroll(scrollRequest);
        searchHits = searchScrollResponse.getHits().getHits(); 
        ElasticSearchTools.logInfo(log, String.valueOf(searchScrollResponse.getHits().getHits().length));
    }
    //删除scrollId
    ClearScrollRequest clearScrollRequest = new ClearScrollRequest(); 
    clearScrollRequest.addScrollId(scrollId);
    ClearScrollResponse clearScrollResponse = client.clearScroll(clearScrollRequest);
    boolean succeeded = clearScrollResponse.isSucceeded();
    ElasticSearchTools.logInfo(log,succeeded?"success":"failed");
    //没有进行异常处理，这里只是简单的关闭一下。
    client.close();
    return null;
}

异步++

其它API

获取本节点信息
public String infoAPI() throws IOException {
    RestHighLevelClient client = ElasticSearchTools.getClientConnection();
    MainResponse response=client.info();
    String infoStr = JSONObject.toJSONString(response);
    ElasticSearchTools.logInfo(log,infoStr);
    client.close();
    return infoStr;
}

结果

{
    "available": true,
    "build": {
        "snapshot": false
    },
    "clusterName": {},
    "clusterUuid": "N4uLCbI2Q262rh0OxqBoFg",
    "fragment": false,
    "nodeName": "node-2",
    "version": {
        "alpha": false,
        "beta": false,
        "build": 99,
        "id": 6010199,
        "luceneVersion": {
            "bugfix": 0,
            "major": 7,
            "minor": 1,
            "prerelease": 0
        },
        "major": 6,
        "minor": 1,
        "rC": false,
        "release": true,
        "revision": 1
    }
}

原文链接:https://www.cnblogs.com/zhangsungelan/p/11378619.html
如有疑问请与原作者联系

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