Scala入门篇

 程序主入口类，基本覆盖了入门需要掌握的Scala知识。主要涵盖，变量定义，常量，类与对象，集合映射等常用方法。

 

package org.lean.scala

import org.learn.clazz.Person
import scala.collection.immutable.HashMap
import scala.io.Source
import java.io.PrintWriter
import java.io.File


object Main {
  private var myName: String = "";
  def main(args: Array[String]) {
    println("HelloWorld");
    var byte_tmp: Byte = 255.toByte
    var short_tmp: Short = 255.toShort;
    var int_tmp: Int = 255;
    var long_tmp: Long = 255.toLong;
    var dbl_tmp: Double = 255.toDouble;
    var flt_tmp: Float = 255.toFloat;
    var str_tmp: String = 255.toString();
    var bool_tmp: Boolean = 255.!=(0);

    println(str_tmp.equals(null));

    var anysTMP = 12; //表示变量
    val anysTMPl = "Good Baby"; //表示常量
    anysTMP.+=(24); //闭包式 同 anysTMP=anysTMP+24;
    println(anysTMP);
    //anysTMPl="Hello";  error,not support
    println(anysTMPl + " HELLO");

    //println(AnotherObj.myName); error,not support
    println(AnotherObj.myAge);

    //Class and Object
    var p = new Person
    p.setName("Hword");
    print(p.getName);

    //Array
    var arTmp = new Array[String](3);
    arTmp(0) = "Good World";
    arTmp(1) = "I'm Jack";
    arTmp(2) = "boast show";
    for (i <- 0 to 2) {
      println(arTmp(i))
    }
    //List
    var listTmp = List(1, 2, 3);
    println(listTmp(0));
    listTmp = 90 :: listTmp; //concat element,but not support different Type of Element
    println(listTmp(0));
    println(listTmp);
    //useful method of List
    var countl = listTmp.count { x => x > 3 }
    println(countl)
    //drop

    println(listTmp.drop(1));
    println(listTmp.dropRight(1));
    //exist check
    println(listTmp.exists { x => x == 90 })
    //filter
    println(listTmp.filter { x => x > 1 })
    //loop for all element,return boolearn result
    println(listTmp.forall { x => x > 0 })
    //loop for all with any method
    listTmp.foreach { x => println(" this is list's foreach =: " + x) }

    //map ,return self by changes
    println(listTmp.map { x => x * x })
    //build string with any string
    println(listTmp.mkString("#"))
    //reverse
    println(listTmp.reverse);
    //sort
    println(listTmp.sortWith({ (c: Int, n: Int) => c > n }))

    //Tuple Section
    val tplTmp = ("Google", "Baidu", 0x9002)
    println(tplTmp);
    println(tplTmp._1); // Note: start index is 1
    println(tplTmp._2);
    println(tplTmp._3);

    //Set And Map
    var setTmp = Set("hao123", "hao360");
    println(setTmp)
    println(setTmp + "hao163")
    var mapTmp = new HashMap[String, String]();
    mapTmp.+=("KEY1" -> "Hao123");
    mapTmp.+=("KEY2" -> "Hao321");
    println(mapTmp("KEY1"));
    println(mapTmp.get("KEY1"));

    //File's read and write
    for (line <- Source.fromFile("d.txt").getLines()) {
      println(line)
    }
    var writer:PrintWriter=new PrintWriter(new File("d.txt"));
    writer.write("Im Test Line");
    writer.close()
    //singleton
    singleObj.name="Hello Scala";
    println(singleObj.name);

  }
  object singleObj{
    var name:String="";
  }
}

 

 

package org.learn.clazz

class Person {
  private var rName: String = "";
  private var age: Int = 255;
  def getName(): String = {
    return rName;
  }
  def setName(name:String)={
    rName=name;
  }
}

 

package org.lean.scala

object AnotherObj {
  private var myName:String="Another";
   var myAge:Int=12;
}

 另外两个文件一个是单态对象定义，一个是Class定义