9.标准输入输出流拷贝文件

了解，开发中不用
若要COPY请使用BufferedInputStream/BufferedOutputStream 或 FileInputStream/FileOutputStream

实现

public class Test02SystemInOutForCopy {
    public static void main(String[] args) throws IOException {
        //改变标准输入流
        System.setIn(new FileInputStream(".\\005IO流\\test.jpg"));
        //改变标准输出流
        System.setOut(new PrintStream(".\\005IO流\\test_system.jpg"));
        InputStream is = System.in;
        PrintStream ps = System.out;
        byte[] arr = new byte[1024];
        int len;
        while((len = is.read(arr)) != -1) {
            ps.write(arr, 0, len);
        }
        is.close();
        ps.close();
    }
}