code: public static void write(Writer writer, CharSequence cs) throws IOException {
          if (null != cs && null != writer) {
              writer.write(cs.toString());
              writer.flush();
          }
      }
docs: 将一段文本全部写入一个writer。
  <p>
  <b style=color:red>注意</b>，它并不会关闭输出流
  
  @param writer
  
  @param cs
  文本
  @throws IOException