关于java--I/O流：文本的复制，从键盘读取数据，写入到文件的简单操作

public class TransStreamDemo2 {
    public static void main(String[] args) throws IOException {
      
        method_1();//需求，将键盘键入的数据写入到文件中，如何操作？
        method_2();//讲一个文本文件内容显示在控制台上，如何操作？
        method_3();//将一个文本文件复制到另一个文件上；如何操作？

    }

    private static void method_3() throws IOException {
        BufferedReader bufr=new BufferedReader( new InputStreamReader(new FileInputStream("F:\\java\\test\\transtreamdemo\\xieruwenjian.txt")));
        //将文本读取进缓冲区
        BufferedWriter bufw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream("F:\\java\\test\\transtreamdemo\\copy_xieruwenjian.txt")));
        //将文本读入到复制的文本当中；
        String line = null;
        while ((line = bufr.readLine()) != null) {
            if ("over".equals(line))
                break;
            bufw.write(line);
            bufw.newLine();
            bufw.flush();
        }

    }

    private static void method_2() throws IOException {
        BufferedReader bufr=new BufferedReader( new InputStreamReader(new FileInputStream("F:\\java\\test\\transtreamdemo\\xieruwenjian.txt")));

        //这一步是从"F:\\java\\test\\transtreamdemo\\xieruwenjian.txt"读取文件
        BufferedWriter bufw=new BufferedWriter(new OutputStreamWriter(System.out));
        //将读取的文件显示在控制台
        String line = null;
        while ((line = bufr.readLine()) != null) {
            if ("over".equals(line))
                break;
            bufw.write(line);
            bufw.newLine();
            bufw.flush();
        }

    }

    private static void method_1() throws IOException {
        BufferedReader bufr=new BufferedReader( new InputStreamReader(System.in));
        //FileWriter fw=new FileWriter("F:\\java\\test\\transtreamdemo\\xieruwenjian.txt");
        //BufferedWriter bufw=new BufferedWriter(fw);
        BufferedWriter bufw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream("F:\\java\\test\\transtreamdemo\\xieruwenjian1.txt")));
        //这是第二种写法;
        String line = null;
        while ((line = bufr.readLine()) != null) {
            if ("over".equals(line))
                break;
            bufw.write(line);
            bufw.newLine();
            bufw.flush();
        }
    }
}
//注意：学习来源于https://www.bilibili.com/video/BV1pt41127na?p=351。