search（6）- elastic4s-CRUD
如果我们把ES作为某种数据库来使用的话，必须熟练掌握ES的CRUD操作。在这之前先更正一下上篇中关于检查索引是否存在的方法：elastic4s的具体调用如下：
//删除索引
val rspExists = client.execute(indexExists("company")).await
if (rspExists.result.exists)
client.execute(deleteIndex("company")).await
在下面我们还会示范如何检查一条记录（document）是否存在的方法。
先示范新建一条记录。一般来讲数据库表都有个唯一字段，最好用ES里的id来代表，否则ES会自动产生一个唯一id，那么随机读取get时就会很不方便。如果新插入的记录id已经在表里存在，ES会替换新的内容，不会产生异常。可以在elastic4s里使用createOnly(true)来强制产生重复id异常：
import com.sksamuel.elastic4s.{ElasticClient, ElasticProperties}
import com.sksamuel.elastic4s.akka._
import akka.actor._
import scala.concurrent.ExecutionContext.Implicits.global
object Lesson05 extends App {
import com.sksamuel.elastic4s.ElasticDsl._
private implicit lazy val system: ActorSystem = ActorSystem()
val akkaClient = AkkaHttpClient(AkkaHttpClientSettings(List("130.1.1.234:9200")))
val client = ElasticClient(akkaClient)
val publisher = indexInto("company").id("c00001")
.fields(
"code" -> "c00001",
"name" -> "人民出版社",
"biztype" -> "出版社",
"addr" -> Map(
"district" -> "北京市东城区",
"address" -> "朝阳门内大街166号"
),
"regdate" -> "1963-02-18",
"contact" -> "65122634@163.com"
).createOnly(true)
val pubExists = client.execute(exists("company","c00001")).await
if (pubExists.isSuccess) {
val createPub = client.execute(publisher).await
if (createPub.isSuccess) {
val pub = client.execute(get("company", "c00001").fetchSourceContext(true)).await
println(s"${pub.result.sourceAsMap}")
} else println(s"${createPub.error.reason}")
} else println(s"${pubExists.error.reason}")
val dstributor = indexInto("company").id("c00002")
.fields(
"code" -> "c00002",
"name" -> "新华文轩出版传媒股份有限公司",
"biztype" -> "出版发行",
"addr" -> Map(
"district" -> "四川省成都市锦江区",
"address" -> "金石路239号4栋1层1号"
),
"regdate" -> "2005-03-09",
"contact" -> "52635286@qq.com"
).createOnly(true)
val grpExists = client.execute(exists("company","c00002")).await
if (grpExists.isSuccess) {
val createGroup = client.execute(dstributor).await
if (createGroup.isSuccess) {
val dstr = client.execute(get("company", "c00002").fetchSourceContext(true)).await
println(s"${dstr.result.sourceAsMap}")
} else println(s"${createGroup.error.reason}")
} else println(s"${grpExists.error.reason}")
val mget = client.execute(multiget(
get("company","c00001"),
get("company","c00002")
)).await
if(mget.isSuccess)
mget.result.items.foreach(i => println(s"${i.sourceAsMap}"))
else println(s"${mget.error.reason}")
scala.io.StdIn.readLine()
system.terminate()
client.close()
}
上面示范了不同类型字段的填写方式，特别是nested字段如addr。每插入一条新记录就用get进行一次验证，输出显示：
HashMap(name -> 人民出版社, regdate -> 1963-02-18, contact -> 65122634@163.com, code -> c00001, addr -> Map(district -> 北京市东城区, address -> 朝阳门内大街166号), biztype -> 出版社)
HashMap(name -> 新华文轩出版传媒股份有限公司, regdate -> 2005-03-09, contact -> 52635286@qq.com, code -> c00002, addr -> Map(district -> 四川省成都市锦江区, address -> 金石路239号4栋1层1号), biztype -> 出版发行)
HashMap(name -> 人民出版社, regdate -> 1963-02-18, contact -> 65122634@163.com, code -> c00001, addr -> Map(district -> 北京市东城区, address -> 朝阳门内大街166号), biztype -> 出版社)
HashMap(name -> 新华文轩出版传媒股份有限公司, regdate -> 2005-03-09, contact -> 52635286@qq.com, code -> c00002, addr -> Map(district -> 四川省成都市锦江区, address -> 金石路239号4栋1层1号), biztype -> 出版发行)
上面提到过，如果我们想把ES当作普通的数据库来使用的话，还是要备齐了CRUD功能。具体操作按照关系数据库方式围绕着唯一键id进行。比如，我们可以用id来检查记录是否已经存在：
val pubExists = client.execute(exists("company","c00001")).await
if (pubExists.isSuccess) {...}
上面我们示范了针对索引的create,read操作。下面讨论一下update：update 可分单笔或批次两类，分别为：updateById, updateByQuery，很明显：updateByQuery是以query作为目标筛选条件的成批update操作。与上面的create操作一样，我们还是需要考虑唯一键id，这个可以在updateById操作里处理：当目标id存在时，用update请求里的字段值更新对应的字段。如目标id不存在的话就把update请求里的字段值当作新记录内容插入：
import com.sksamuel.elastic4s.http.JavaClient import com.sksamuel.elastic4s.requests.common.RefreshPolicy import com.sksamuel.elastic4s.{ElasticClient, ElasticProperties} import scala.concurrent.ExecutionContext.Implicits.global object Lesson06 extends App { import com.sksamuel.elastic4s.ElasticDsl._ val esjava = JavaClient(ElasticProperties("http://localhost:9200")) val client = ElasticClient(esjava) val doc1 = updateById("company","t00001") .docAsUpsert( Map( "code" -> "t00001", "name" -> "test company1" ) ) val doc2 = updateById("company","t00002") .docAsUpsert( Map( "code" -> "t00002", "name" -> "test company2" ) ) val doc3 = updateById("company","t00003") .docAsUpsert( Map( "code" -> "t00003", "name" -> "test company3" ) ) val updateAll = for { _ <- client.execute(doc1) _ <- client.execute(doc2) _ <- client.execute(doc3) } yield() updateAll.await val getResults = client.execute(multiget( get("company","t00001").fetchSourceInclude("code","name"), get("company","t00002").fetchSourceInclude("code","name"), get("company","t00003").fetchSourceInclude("code","name") ) ).await getResults.result.items.foreach(i => println(i.sourceAsMap)) client.close() }
成批更新比较麻烦，因为通常每条记录的更新都可能涉及到当前记录的字段值，或作为判断条件，或为更新值，我们需要使用并处理当前记录中某些字段。这就需要在数据层面运行某些计算方法，可以用脚本语言来实现这样的功能，如下：
import com.sksamuel.elastic4s.requests.script.Script
val script = "ctx._source.fullname = ctx._source.code+' '+ctx._source.name"
val updateByQ = updateIn("company")
.query(matchQuery("name","test"))
.script(Script(script,Some("painless")))
val qupResult = client.execute(updateByQ).await
val getResults = client.execute(multiget(
get("company","t00001"),
get("company","t00002"),
get("company","t00003")
)
).await
getResults.result.items.foreach(i => println(i.sourceAsMap))
与update一样，delete也分单个或成批删除模式。delete by Id 示例如下：
(for {
_ <- client.execute(delete("t00001").from("company"))
_ <- client.execute(deleteByQuery("company", "t00002"))
} yield()).await
delete by Query 用法如下：
import com.sksamuel.elastic4s.Index._
client.execute(
deleteByQuery(toIndex("company"),
termQuery("code","t00003"))
).await
