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Client
Client 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Clinet
client.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ElasticSearch
IndexResponse 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IndexRequest
IndexRequest 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/type
MultiGetResponse 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/type
for(MultiGetItemResponse item:multiGetResponse){
GetResponse response = item.getResponse();
System.out.println(response.getSourceAsString());
} //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()){
//...
} //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());
} //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
//BulkProcessor
BulkProcessor bulkProcessor = BulkProcessor.builder(client, new BulkProcessor.Listener() {
@Override
public void beforeBulk(long arg0, BulkRequest arg1) {
//批量执行前做的事情
System.out.println("bulk api action starting...");
}
@Override
public void afterBulk(long arg0, BulkRequest arg1, Throwable arg2) {
System.out.println("exception:bukl api action ending...:"+arg2.getMessage());
}
@Override
public 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.