学习笔记:java的键盘输入输出、if语句、循环结构

键盘输入输出的两种方法 package Str; import com.sun.xml.internal.ws.api.model.wsdl.WSDLOutput; import java.util.Scanner; public class Sys_1 { public static void main(String[] args){ Scanner rea=new Scanner(System.in); System.out.println(rea.next()); } } import java.io.*; public class