Java官方操纵byte数组的方式

/**
    * 将所有的字节数组全部写入内存中，之后将其转化为字节数组
    */
    public static void main(String[] args) throws IOException {
        String str1 = "132";
        String str2 = "asd";
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        os.write(str1.getBytes());
        os.write(str2.getBytes());
        byte[] byteArray = os.toByteArray();
        System.out.println(new String(byteArray));
    }

/**
    *   从内存中读取字节数组
    */
    public static void main(String[] args) throws IOException {
        String str1 = "132asd";
        byte[] b = new byte[3];
        ByteArrayInputStream in = new ByteArrayInputStream(str1.getBytes());
        in.read(b);
        System.out.println(new String(b));
        in.read(b);
        System.out.println(new String(b));
    }