目的：在实践3中搭建了运算环境，这里学会如何使用该环境进行具体的运算和相关的排序组合等。
- 由数据库mongodb操作如find，aggregate等可知它们的返回类型是FindObservable、AggregateObservable等，可看作每个数据库的操作都是Observable，
- 因为之sort和projection等相应的操作都是在API中的FondObsevable里面的，且返回FondObsevable。
/** * Sets a document describing the fields to return for all matching documents. * * [[http://docs.mongodb.org/manual/reference/method/db.collection.find/ Projection]] * @param projection the project document, which may be null. * @return this */ def projection(projection: Bson): FindObservable[TResult] = { wrapped.projection(projection) this } /** * Sets the sort criteria to apply to the query. * * [[http://docs.mongodb.org/manual/reference/method/cursor.sort/ Sort]] * @param sort the sort criteria, which may be null. * @return this */ def sort(sort: Bson): FindObservable[TResult] = { wrapped.sort(sort) this }
- 可以引入新的类型，能够便于使用
type MGOFilterResult = FindObservable[Document] => FindObservable[Document]
一、简单查询操作：排序、投影
1、排序
- 引入包
import org.mongodb.scala.model.Sorts._
- 在Sorts里面能看到里面的是具体方法
/** * Create a sort specification for an ascending sort on the given fields. * * @param fieldNames the field names, which must contain at least one * @return the sort specification * @see [[http://http://docs.mongodb.org/manual/reference/operator/meta/orderby Sort]] */ def ascending(fieldNames: String*): Bson = JSorts.ascending(fieldNames.asJava) /** * Create a sort specification for an ascending sort on the given fields. * * @param fieldNames the field names, which must contain at least one * @return the sort specification * @see [[http://http://docs.mongodb.org/manual/reference/operator/meta/orderby Sort]] */ def descending(fieldNames: String*): Bson = JSorts.descending(fieldNames.asJava) /** * Create a sort specification for the text score meta projection on the given field. * * @param fieldName the field name * @return the sort specification * @see [[http://http://docs.mongodb.org/manual/reference/operator/projection/meta/#sort textScore]] */ def metaTextScore(fieldName: String): Bson = JSorts.metaTextScore(fieldName) /** * Combine multiple sort specifications. If any field names are repeated, the last one takes precendence. * * @param sorts the sort specifications * @return the combined sort specification */ def orderBy(sorts: Bson*): Bson = JSorts.orderBy(sorts.asJava)
- 应用如下：
import org.mongodb.scala.model.Projections._ import org.mongodb.scala.model.Sorts._ val sort:MGOFilterResult=a=>a.sort(descending("age"))//“age”降序 val F1:Future[List[Document]] = DAO(dxt.setCommand(Find(andThen = Some(sort)))) F1.onComplete { case Success(docs:List[Document]) => docs.foreach(Person().fromDocument(_).toSink()) println("-------------------------------") case Failure(err) => println(s"显示错误：${err.getMessage}") }
2、投影
- 选择需要的字段（首页只出现商品的图片，价钱、不全部出现相关全部信息。。。）
- 从数据库内获取字段，其他的不显示出来，这里需要对Model里面的toSink进行一些修改，使它在没有获取对应数据时，不在控制台那里显示
def toSink()(implicit mat: ActorMaterializer) = { println("---------------------------------------") if (ctx.lastName!=null) { println(s"LastName: ${ctx.lastName}")} if (ctx.firstName!=null) { println(s"firstName: ${ctx.firstName}")} if (ctx.age!=0) { //这里是不能设置为0的！！！其他的是空的就不理它 println(s"age: ${ctx.age}")} if (!ctx.phones.isEmpty) { println(s"phones: ${ctx.phones}")} if (!ctx.address.isEmpty) { println(s"address: ${ctx.address}")} if (!ctx.picture.isEmpty) { val path = s"/img/${ctx.firstName}.jpg" FileStreaming.ByteArrayToFile(ctx.picture, path) println(s"picture saved to: ${path}") } }
- 应用如下
import org.mongodb.scala.model.Projections._ val proj: MGOFilterResult = a => a.projection(and(include("firstName"),excludeId())) val F2:Future[List[Document]] = DAO(dxt.setCommand(Find(andThen = Some(proj)))) F2.onComplete { case Success(docs:List[Document]) => docs.foreach(Person().fromDocument(_).toSink()) println("-------------------------------") case Failure(err) => println(s"显示错误：${err.getMessage}") }
二、数据库操作的使用手册
- 在com.mongodb.client.model包中包含CountOptions等Options，类内有各种选项。原本在casbah包内的，casbah【 end-of-life (EOL）】，迁移mongo-scala-driver。在下列的包中：
1、Count
//mongodb命令:db.personal.count({"age":{$gt:18}}) ==》结果：1 import org.mongodb.scala.model.Filters._ import com.mongodb.client.model.CountOptions._ val countOptions:CountOptions=new CountOptions().skip(1) val q=dxt.setCommand(Count(Some(gt("age",18)),Some(countOptions))) DAO(q).foreach(println)//println:0
2、Distict
3、Find
//db.personal.findOne() val p=new Person() val ctxFindFirst :Future[Person]=DAO(dxt.setCommand(Find(converter=Some(p.fromDocument _),firstOnly=true))) ctxFindFirst.andThen { case Success(doc) =>doc.toSink() //foreach(Person().fromDocument(_).toSink()) println("-------------------------------") case Failure(err) => println(s"显示错误：${err.getMessage}") } ===》 --------------------------------------- LastName: Wang firstName: Susan age: 18 phones: List(BsonString{value='137110998'}, BsonString{value='189343661'}) address: List(Address(Sz,101992), Address(gz,231445)) picture saved to: /img/Susan.jpg -------------------------------
4、Aggregate
//db.mycol.aggregate([{$group : {_id : "$lastName", num_tutorial : {$sum : 1}}}]) import org.mongodb.scala.model.Aggregates._ val a:Bson=group("$lastName", Accumulators.sum("num_tutorial", 1)) val q:Future[List[Person]]=DAO(dxt.setCommand(Aggregate(Seq(a)))) q.onComplete{ case Success(value)=>value.foreach(println) }
注意：从org.mongodb.scala的API中可得到相关的信息，它们可以返回Bson的，但是也可以在FindObservable中看到，但是此时它们返回的类型不同。
5、MapReduce
//db.personal.mapReduce( function() { emit(this.lastName,1); }, function(key, values) {return Array.sum(values)}, { query:{firstName:"j"}, out:"total" } )
6、Insert
//db.collection.insertOne() // db.collection.insertMany() val p1=Person("","",12).toDocument val p2=Person("","",23).toDocument val p=DAO(dxt.setCommand(Insert(Seq(p1,p2))))
7、Delete
//db.personal.remove({"age":23},1) val p = DAO(dxt.setCommand(Delete(equal("age",23),None,true))) p.onComplete{ case Success(value)=>println("OK") }
8、Update
//db.personal.update({"lastName":"Wang"},{$set:{"age":18}}) org.mongodb.scala.model.Updates._ val D :Future[List[Person]]=DAO(dxt.setCommand(Update(equal("age",18),set("age","12"),None,true))) D.onComplete { case Success(docs) =>println("OK") println("-------------------------------") case Failure(err) => println(s"显示错误：${err.getMessage}") }
9、BulkWrite
10、DropCollection
//db.dbs.drop() val q=DAO(dxt.setCommand(DropCollection("dbs"))) q.onComplete{ case Success(value)=>print("成功！") }
11、CreateCollection
//db.createCollection("dbs") val q=DAO(dxt.setCommand(CreateCollection("dbs"))) //还有options的选项，如count那里一样添加就好了 q.onComplete{ case Success(value)=>print("成功！") }
12、ListCollection
//show tables val q:Future[List[Document]]=DAO(dxt.setCommand(ListCollection("mydb"))) q.foreach(println)//不过出来的是比较全面信息，什么type、index都有
13、CreateView
//db.createView("View1","personal",[{$group : {_id : "$lastName", num_tutorial : {$sum : 1}}}]) import org.mongodb.scala.model.Aggregates._ val a:Bson=group("$lastName", Accumulators.sum("num_tutorial", 1)) val q:Future[List[Person]]=DAO(dxt.setCommand(CreateView("View1","personal",Seq(a)))) q.onComplete{ case Success(value)=>println("OK") }
14、CreateIndex
//db.personal.createIndex({"age":-1},{background: true})？ import org.mongodb.scala.model.Indexes._ import com.mongodb.client.model.IndexOptions._ val countOptions:IndexOptions=new IndexOptions().background(true) val q=dxt.setCommand(CreateIndex(descending("age"),Some(IndexOptions)))//注意升降 DAO(q).onComplete{ case Success(v)=>println("成功") }
15、DropIndexByName
//db.personal.dropIndex("date_1") val q=dxt.setCommand(DropIndexByName("date_1")) DAO(q).onComplete{ case Success(v)=>println("成功") }
16、DropIndexByKey
//主要是升降ascending、descending val q=dxt.setCommand(DropIndexByKey(ascending("age"))) DAO(q).onComplete{ case Success(v)=>println("成功") }
17、DropAllIndexes
val q:Future[List[Person]]=DAO(dxt.setCommand(DropAllIndexes())) q.onComplete{ case Success(value)=>println("OK") }