请教高人
前几天做项目时遇到一个问题，百思不得其解，故发出来请高人指点迷津,
功能是与c++的一个系统进行通信，报文结构：6字节头+报文体，使用a方法发送，对方可以正常接收，使用b方法发送时，对方可以正常接收报文头，但在接收报文体时，报文体的开始位置总是出现乱码。
代码大致如下：
private void a(String str,int type,int scn) {byte buffer[];str=str+"\0";int len = str.length() + 6;buffer = new byte[len];buffer[5] = (byte) ((scn >> 8) & 0xff);buffer[4] = (byte) (scn & 0xff);buffer[3] = (byte) ((type >> 8) & 0xff);buffer[2] = (byte) ((type) & 0xff);buffer[1] = (byte) ((len >> 8) & 0xff);buffer[0] = (byte) (len & 0xff);try {System.arraycopy(str.getBytes("UTF-8"), 0, buffer, 6, len - 6);} catch (UnsupportedEncodingException e) {e.printStackTrace();} socket = new Socket(ip, port); os = socket.getOutputStream();DataOutputStream dos=new DataOutputStream(os); dos.write(buffer); dos.flush();}private void b(String str,int type,int scn) {byte buffer[];str=str+"\0";int len = str.length() + 6;buffer = new byte[len];buffer[5] = (byte) ((scn >> 8) & 0xff);buffer[4] = (byte) (scn & 0xff);buffer[3] = (byte) ((type >> 8) & 0xff);buffer[2] = (byte) ((type) & 0xff);buffer[1] = (byte) ((len >> 8) & 0xff);buffer[0] = (byte) (len & 0xff); socket = new Socket(ip, port); os = socket.getOutputStream();DataOutputStream dos=new DataOutputStream(os); dos.write(buffer); dos.write(str.getBytes("UTF-8")); dos.flush();}