使用java NIO及高速缓冲区写入文件过程解析

byte[] bytes = Files.readAllBytes(Paths.get("E://pdf//aaa//html//text.txt").normalize());    String text = IOUtils.toString(bytes);    String xml = text.substring(text.indexOf("<tbody>"));    InputSource inputXML = new InputSource( new StringReader( xml ) );    XPath xPath = XPathFactory.newInstance().newXPath();    NodeList nodes = (NodeList) xPath.evaluate("/tbody/tr", inputXML, XPathConstants.NODESET);    int length = nodes.getLength();    Path file = Paths.get("E://pdf//aaa//html//out.txt");    try (BufferedWriter writer = Files.newBufferedWriter(file, Charset.defaultCharset(), StandardOpenOption.CREATE)) {      for (int i = 0; i < length; i++) {        Node node = nodes.item(i);        NodeList childList = (NodeList) xPath.evaluate("td", node, XPathConstants.NODESET);        for (int j = 0; j < childList.getLength(); j++) {          Node child = childList.item(j);          String content = child.getTextContent();          //System.out.print(content);          writer.write(content);          if (j <childList.getLength() - 1) {            writer.write("/t");          }        }        writer.newLine();      }    }