System.in/out

System.out是从控制台输出数据

System.in是从控制台输入数据

try(InputStream is = System.in;){

while(true)

 int i = is.read;

System.out.println(i);// 输入a会得到 97 13 10 //a 回车 换行

Scanner可以逐行读取，比System.in.read方便

Scanner s = new Scanner(System.in);

while(true)

string line = s.nextLine()

System.out.println(line);

}