2021-09-17 IO流(改变标准输入输出设备)

import java.io.*;

public class TransStreamDemo3 {

    public static void main(String[] args) throws IOException {
        System.setIn(new FileInputStream("E:\\CopyPic.java"));
        System.setOut(new PrintStream("E:\\zzz.txt"));
        // 键盘的最常见写法
        BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufw = new BufferedWriter(new OutputStreamWriter(System.out));

        String line;
        while ((line = bufr.readLine()) != null) {
            bufw.write(line.toUpperCase());
            bufw.newLine();
        }
        bufw.flush();
        bufw.close();
        bufr.close();
    }

}