IO流 打印流

一共可以分成3类
1:纯字节流
2:字符流
3:混合流
(混合流最好)

混合流

BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        PrintStream print = new PrintStream(System.out, true);// 字节流
        String s1, end = "end";
        while ((s1 = reader.readLine()) != null) {
            print.print(s1 + "\n");
            if (s1.equals(end))
                break;
        }

字符流

BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter writer = new PrintWriter(System.out, true);// 字符流
        String s1, end = "end";
        while ((s1 = reader.readLine()) != null) {
            writer.println(s1);
            if (s1.equals(end))
                break;
        }

字节流

BufferedInputStream in = new BufferedInputStream(System.in);
        BufferedOutputStream out = new BufferedOutputStream(System.out);
        int end = 1;
        byte[] bs = new byte[6000];
        while ( in.read()!=-1 ) {
            in.read(bs);
            out.write(bs);
            out.flush();
            if (Integer.valueOf(end).byteValue() == in.read())break;
        }