@Test

public void test9() throws Exception {

    FileOutputStream fos = new FileOutputStream("C:\\Users\\Mi\\Documents\\io\\printStream.txt");

    //重定向打印流。自动刷新（写入换行符或"\n"时flush）

    PrintStream ps = new PrintStream(fos, true);

    System.setOut(ps);

    for (int i = 0; i <= 255 ; i++) {

        //打印

        System.out.print((char)i);

        if (i % 50 == 0){

            System.out.println();

        }

    }

    ps.close();

}