If the process of opening and reading a file fails, you may prefer to return aTryor an emptyList[String]. See Recipes 20.5 and 20.6 for examples of those approaches. Update: Reading a file with Try, Success, and Failure This code shows how you can read a text file into a list of ...
1.导入是mvn工程没有run 原因:是由于没有把项目配置maven项目。 解决 idea本身缓存问题 解决:清理缓存重启IDEA file-->invalidate Cache/restart 之后再重新build。 还不行的话,设置一下file-->project structure-->Module: paths里面的编译路径Complier output: ... ...
This book provides astep-by-stepguide for thecomplete beginnerto learn Scala. It is particularly useful to programmers, data scientists, big data engineers, students, or just about anyone who wants toget up to speed fastwith Scala (especially within an enterprise context). You get to build a...
def main(args: Array[String]): Unit = { //(1)基本类型转String类型(语法:将基本类型的值+"" 即可) var str1 : String = true + "" var str2 : String = 4.5 + "" var str3 : String = 100 +"" //(2)String类型转基本数值类型(语法:调用相关API) var s1 : String = "12" var n1 ...
reader.readNext();} 1. 2. 3. 4. 5. 6. 7. 8. 如果字段中嵌有换行符,就需要完整读取每个文件,然后解析各段。 case class Person(name:String,favoriteAnimal:String)val input = sc.wholeTextFile(inputFile)val result = input.flatMap{ case (_,txt) => val reader = new CSVReader(new String...
case class AllPhoneNumberRead(fileName: String) class PhoneNumbersPublisher(actor: ActorRef) extends ActorRef { def receive = { case ReadPhoneNumbers => //list phone numbers actor ! AllPhoneNumberListed(List(1110, )) } } class PhoneNumberFinder(actor: ActorRef) extends ActorRef { ...
val tableName:String = "mytest" val dbUser: String = "root" val dbPasswd: String = "123456" val dbHost: String = "127.0.0.1" val dbPort: String = "3306" // 代码 val conn_str = "jdbc:mysql://" + dbHost + ":" + dbPort + "/" + dbName + "?useSSL=false&user=" + dbUs...
org.apache.spark.sql.SparkSession object WorkingWithAvroFile { def main(ar : Array[String])...
importjava.util.function._importscala.compat.java8.FunctionConverters._valfoo:Int=>Boolean= i => i >7deftestBig(ip:IntPredicate) = ip.test(9) println(testBig(foo.asJava))// Prints truevalbar =newUnaryOperator[String]{defapply(s:String) = s.reverse }List("cod","herring").map(bar.asSc...
[String]=env.readTextFile(inputFilePath)// 对 DataSet进行转换操作valresultDataSet:DataSet[(String,Int)]=inputDataSet.flatMap(_.split(" "))// 把每一行数据打散,分词.map((_,1))// 转换成二元组.groupBy(0)// 把二元组中下标为0的第一个元素,作为key分组.sum(1)// 把当前key中所有的第二个...