docs: public Object getValue(byte[] bs, Charset charset) {
          if (String.class == field.getType()) {
              if (isDynamicField()) {
                  return (new String(bs, offsize, bs.length - offsize, charset)).trim();
              }
              return (new String(bs, offsize, size, charset)).trim();
          } else if (long.class == field.getType()) {
              return BytesUtil.buff2long(bs, offsize);
          } else if (int.class == field.getType()) {
              return (int) BytesUtil.buff2long(bs, offsize);
          } else if (java.util.Date.class == field.getType()) {
              return new Date(BytesUtil.buff2long(bs, offsize) * 1000);
          } else if (byte.class == field.getType()) {
              return bs[offsize];
          } else if (boolean.class == field.getType()) {
              return bs[offsize] != 0;
          }
          throw new FdfsColumnMapException(field.getName() + "获取值时未识别的FdfsColumn类型" + field.getType());
      }