//客户端通过此方法与Servlet通信
             public void inTurnServer(){
        try{
            String url = "http://localhost:8080/my/Test";
            str = tfd.getString();
            HttpConnection conn = (HttpConnection)Connector.open(url);
            // 设置请求类型为POST    
            conn.setRequestMethod(HttpConnection.POST);
         // 设置一般的请求属性    
            conn.setRequestProperty("Content-Type",    
                    "application/x-www-form-urlencoded");    
            conn.setRequestProperty("User-Agent",    
                    "Profile/MIDP-1.0 Configuration/CLDC-1.0");    
            conn.setRequestProperty("Content-Language", "en-US");    
            conn.setRequestProperty("Accept", "application/octet-stream");    
            conn.setRequestProperty("Connection", "close"); 
            String info = "str"+str;
         // 转换显字节流    
            byte[] data = info.getBytes();
         // 设置写入流的长度    
            conn.setRequestProperty("Content-Length", Integer    
                    .toString(data.length));
            OutputStream os = conn.openOutputStream();    
            os.write(data);
            os.close();
            
         // 得到Http响应代码    
            int rc = conn.getResponseCode();    
            // 正常响应    
            if (rc == HttpConnection.HTTP_OK)    
            {    
                // 构建输入流    
                DataInputStream dism = new DataInputStream(conn    
                        .openInputStream());    
                // 读取服务器返回的字节流    
                String result = dism.readUTF();    
                dism.close();    
                // 判断    
                if (result.equals("true"))    
                {    
                      System.out.println("OK!"); 
                }    
                if (result.equals("false"))    
                {    
                    System.out.println("ERROR!");
               }    
            }
            
        }catch(Exception ex){
            ex.printStackTrace();
        }
/////////////////////////////////////////////////////////////////////////////////////

    @Override//服务端Servlet
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String str = request.getParameter("str");
        // 构建输出流    
        ByteArrayOutputStream baos = new ByteArrayOutputStream();    
        DataOutputStream dos = new DataOutputStream(baos);  
        
        if("A".equals(str)){
            dos.writeUTF("true");
        }else{
            dos.writeUTF("false");
        }
        byte[] data1 = baos.toByteArray();    
        // 设置服务器响应参数    
        response.setStatus(HttpServletResponse.SC_OK);    
        response.setContentLength(data1.length);    
        response.setContentType("application/octet-stream");    
        OutputStream os = response.getOutputStream(); 
        os.write(data1);    
        os.close();
    }