/**录入键盘输入字母并将小写变为大写*/import java.io.*;class readin {public static void main(String[] args)throws IOException {InputStream in = System.in;//引入输入流StringBuilder sb = new StringBuilder();//新建一个缓冲区while(true){int ch = in.read();//读入键盘输入if(ch=='\r')continue;if(ch=='\n'){String s = sb.toString();//讲读入输入转换为字符型if("over".equals(s))//判断S是否为OVERbreak;elseSystem.out.println(s.toUpperCase());//打印出字母大写sb.delete(0,sb.length());}elsesb.append((char)ch);}}}
简而言之：
最实用的
BufferedReader bufr = new Bufferedread(new InputStreamReader(System.in));//读入键盘输入转换为字符流，在用缓冲区优化
