ElasticSearch API for JAVA 学习笔记

本篇学习笔记来源于ES官方网站的指导文档：ES JAVA API

Client

Client是一个类，通过这个类可以实现对ES集群的各种操作：Index, Get, Delete , Search，以及对ES集群的管理任务。

Client的构造需要基于TransportClient

TransportClient

TransportClient可以远程连接ES集群，通过一个传输模块，但是它不真正的连接到集群，只是获取集群的一个或多个初始传输地址，在每次请求动作时，才真正连接到ES集群。

Settings

Settings类主要是在启动Client之前，配置一些属性参数，主要配置集群名称cluster.name，还有其他参数：

client.transport.sniff  是否为传输client添加嗅探功能

client.transport.ignore_cluster_name 设为true，忽略连接节点的集群名称验证

client.transport.ping_timeout 设置ping节点时的时间限，默认5s

client.transport.nodes_sampler_interval 设置sample/ping nodes listed 间隔时间，默认5s

//通过Settings类设置属性参数Settings settings = Settings.settingsBuilder().put("cluster.name","index-name").build();//启动ClientClient client = TransportClient.builder().settings(settings).build().addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("192.168.xxx.xxx"),9300));//如果不需要设置参数，直接如下/*Client client = TransportClient.builder().build().addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("192.168.xxx.xxx"),9300));*///关闭Clinetclient.close();

Document API

主要分为以下类：Index API , Get API , Delete API , Update API, Multi Get API, Bulk API

es中的增删改查

Index API可以索引一个典型的JSON文档到指定的索引中，并且可以使它可以检索。

产生JSON

JSON产生可以有以下几种方式：

手动拼接一个JSON字符串

使用Map

使用第三方库，比如Jackson

使用内置的XContentFactory.jsonBuilder()

每种类型都会转换为byte[]，因此如果对象已经是这种形式，可以直接使用，jsonBuilder是一个高度优化了的JSON产生器，它直接构造byte[]

通过下边的代码讲解四种方法：index-api, get-api, delete-api, update-api

/** * es-api的方法学习： * 1.prepareIndex方法：索引数据到ElasticSearch * 2.prepareGet方法:获取信息 * 3.prepareDelete方法：删除信息 * 4.update方法：更新信息 *   4.1 upsert：在使用update方法时： *       a:针对文档不存在的情况时，做出index数据的操作,update无效； *        b:如果文档存在，那么index数据操作无效，update有效； */public static void main(String[] args) throws IOException, InterruptedException, ExecutionException {//通过Settings类设置属性参数  Settings settings = Settings.settingsBuilder().put("cluster.name","myApp").build();    //启动Client  Client client = null;try {client = TransportClient.builder().settings(settings).build().          addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("101.200.124.27"),9300));} catch (UnknownHostException e) {e.printStackTrace();}  //执行操作SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");XContentBuilder jsonBuilder = XContentFactory.jsonBuilder().startObject().field("user","yuchen").field("interest","reading book").field("insert_time",df.format(new Date())).endObject();//1.prepareIndex方法：索引数据到ElasticSearchIndexResponse response = client.prepareIndex("index-test","weibo","4").setSource(jsonBuilder).get();String _index = response.getIndex();String _type = response.getType();String _id = response.getId();long _version = response.getVersion();boolean created = response.isCreated();System.out.println(_index+" "+_type+" "+_id+" "+_version+" "+created);//2.prepareGet方法:获取信息GetResponse getResponse = client.prepareGet("index-test","weibo","1").get();System.out.println(getResponse.getSourceAsString());//3.prepareDelete方法：删除信息DeleteResponse deleteResponse = client.prepareDelete("index-test","weibo","4").get();System.out.println(deleteResponse.isFound());//4.update方法：更新信息UpdateRequest updateRequest = new UpdateRequest();updateRequest.index("index-test");updateRequest.type("weibo");updateRequest.id("1");updateRequest.doc(XContentFactory.jsonBuilder().startObject().field("interest","music").endObject());UpdateResponse updateResponse = client.update(updateRequest).get();System.out.println(updateResponse.isCreated());//update方法： 可以为已有的文档添加新的字段UpdateResponse updateResponse2 = client.prepareUpdate("index-test", "weibo", "1").setDoc(XContentFactory.jsonBuilder().startObject().field("interest2","reading").endObject()).get();System.out.println(updateResponse2.isCreated());//4.1 upsert：在使用update方法时，a:针对文档不存在的情况时，做出index数据的操作,update无效；//  b:如果文档存在，那么index数据操作无效，update有效；//先构建一个IndexRequestIndexRequest indexRequest = new IndexRequest("index-test","weibo","14");indexRequest.source(XContentFactory.jsonBuilder().startObject().field("user","yuchen2").field("interest","eating").field("insert_time",df.format(new Date())).endObject());//再构建一个UpdateRequest，并用IndexRequest关联UpdateRequest updateRequest3 = new UpdateRequest("index-test","weibo","14");updateRequest3.doc(XContentFactory.jsonBuilder().startObject().field("interest2","love").endObject()).upsert(indexRequest);client.update(updateRequest3).get();if(client != null){client.close();  }}

批量操作

Multi Get Api 和 Bulk Api可进行批量的增删改查

使用Multi Get Api 批量获取：

//1. Muti-get Api//可以指定单个id,也在index,type下指定一个id-list；也可以指定别的index/typeMultiGetResponse multiGetResponse = client.prepareMultiGet().add("index-test","weibo","1")//指定单个id.add("index-test","weibo","11","13","14")//指定一个id-list.add("index-other","news","1","3").get();//指定别的index/typefor(MultiGetItemResponse item:multiGetResponse){GetResponse response = item.getResponse();System.out.println(response.getSourceAsString());}

Bulk Api批量增加：

//2.Bulk Api:可以进行批量index和批量删除操作//2.1批量增加BulkRequestBuilder bulkRequest = client.prepareBulk();bulkRequest.add(client.prepareIndex("index-test", "weibo", "20")        .setSource(XContentFactory.jsonBuilder()                .startObject()                    .field("user", "yuchen20")                    .field("postDate", new Date())                    .field("message", "trying out Elasticsearch")                .endObject()              )          );bulkRequest.add(client.prepareIndex("index-test", "weibo", "21")        .setSource(XContentFactory.jsonBuilder()                .startObject()                    .field("user", "yuchen21")                    .field("postDate", new Date())                    .field("message", "trying out Elasticsearch")                .endObject()              )          );BulkResponse bulkResponse = bulkRequest.get();if(bulkResponse.hasFailures()){//...}

Bulk Api批量删除：

//2.2批量删除BulkRequestBuilder bulkRequest = client.prepareBulk();bulkRequest.add(client.prepareDelete("index-test", "weibo", "20")          );bulkRequest.add(client.prepareDelete("index-test", "weibo", "21")          );BulkResponse bulkResponse = bulkRequest.get();if(bulkResponse.hasFailures()){System.out.println("bulk error:"+bulkResponse.buildFailureMessage());}

Bulk Api 批量更新

//2.3批量更新BulkRequestBuilder bulkRequest = client.prepareBulk();bulkRequest.add(client.prepareUpdate("index-test", "weibo", "11").setDoc(XContentFactory.jsonBuilder().startObject().field("country","China")//新添加字段.endObject())          );bulkRequest.add(client.prepareUpdate("index-test", "weibo", "13").setDoc(XContentFactory.jsonBuilder().startObject().field("user","yuchen13")//更新字段.endObject())          );BulkResponse bulkResponse = bulkRequest.get();if(bulkResponse.hasFailures()){System.out.println("bulk error:"+bulkResponse.buildFailureMessage());}

BulkProcessor设置批量请求的属性

//BulkProcessorBulkProcessor bulkProcessor = BulkProcessor.builder(client, new BulkProcessor.Listener() {@Overridepublic void beforeBulk(long arg0, BulkRequest arg1) {//批量执行前做的事情System.out.println("bulk api action starting...");}@Overridepublic void afterBulk(long arg0, BulkRequest arg1, Throwable arg2) {System.out.println("exception:bukl api action ending...:"+arg2.getMessage());}@Overridepublic void afterBulk(long arg0, BulkRequest arg1, BulkResponse arg2) {//正常执行完毕后...System.out.println("normal:bukl api action ending...");}})//设置多种条件，对批量操作进行限制，达到限制中的任何一种触发请求的批量提交.setBulkActions(1000)//设置批量操作一次性执行的action个数，根据请求个数批量提交//.setBulkSize(new ByteSizeValue(1,ByteSizeUnit.KB))//设置批量提交请求的大小允许的最大值//.setFlushInterval(TimeValue.timeValueMillis(100))//根据时间周期批量提交请求//.setConcurrentRequests(1)//设置允许并发请求的数量//设置请求失败时的补偿措施，重复请求3次//.setBackoffPolicy(BackoffPolicy.exponentialBackoff(TimeValue.timeValueMillis(100), 3)).build();for(int i =0;i<100000;i++){bulkProcessor.add(new IndexRequest("index-test","weibo2",""+i).source(XContentFactory.jsonBuilder().startObject().field("name","yuchen"+i).field("interest","love"+i).endObject()));}bulkProcessor.awaitClose(5, TimeUnit.MINUTES);//释放bulkProcessor资源System.out.println("load succeed!");

默认的参数：

• sets bulkActions to 1000
• sets bulkSize to 5mb
• does not set flushInterval
• sets concurrentRequests to 1
• sets backoffPolicy to an exponential backoff with 8 retries and a start delay of 50ms. The total wait time is roughly 5.1 seconds.