java control中获取requestBody的内容

在post请求时，如果参数通过@RequestBody的json提交到后台，
后台想获取body参数体时，可以通过读流的方式获取
下面的readBodyAsString方法即为获取的json字符串

public static String readBodyAsString(HttpServletRequest request)
    {
        InputStream is = null;
        StringBuilder sb = new StringBuilder();
        try
        {
            is = request.getInputStream();

            byte[] b = new byte[4096];
            for (int n; (n = is.read(b)) != -1;)
            {
                sb.append(new String(b, 0, n));
            }
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        finally
        {
            if (null != is)
            {
                try
                {
                    is.close();
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
        }

        return sb.toString();
    }

如果是get请求，key-value方式，上面方法将获取不到，获取为""