在页面上显示各种文档中的内容。在servlet中的逻辑    word：    BufferedInputStream bis = null;  URL url = null;  HttpURLConnection httpUrl = null; // 建立链接  url = new URL(urlReal);  httpUrl = (HttpURLConnection) url.openConnection();// 连接指定的资源  httpUrl.connect();// 获取网络输入流  bis = new BufferedInputStream(httpUrl.getInputStream());    String bodyText = null;  WordExtractor ex = new WordExtractor(bis);  bodyText = ex.getText();  response.getWriter().write(bodyText);    excel：    BufferedInputStream bis = null;  URL url = null;  HttpURLConnection httpUrl = null; // 建立链接  url = new URL(urlReal);  httpUrl = (HttpURLConnection) url.openConnection();// 连接指定的资源  httpUrl.connect();// 获取网络输入流  bis = new BufferedInputStream(httpUrl.getInputStream());    content = new StringBuffer();  HSSFWorkbook workbook = new HSSFWorkbook(bis);  for (int numSheets = 0; numSheets < workbook.getNumberOfSheets(); numSheets++) {  HSSFSheet aSheet = workbook.getSheetAt(numSheets);// 获得一个sheet  content.append("/n");  if (null == aSheet) {  continue;  }  for (int rowNum = 0; rowNum <= aSheet.getLastRowNum(); rowNum++) {  content.append("/n");  HSSFRow aRow = aSheet.getRow(rowNum);  if (null == aRow) {  continue;  }  for (short cellNum = 0; cellNum <= aRow.getLastCellNum(); cellNum++) {  HSSFCell aCell = aRow.getCell(cellNum);  if (null == aCell) {  continue;  }  if (aCell.getCellType() == HSSFCell.CELL_TYPE_STRING) {  content.append(aCell.getRichStringCellValue()  .getString());  } else if (aCell.getCellType() == HSSFCell.CELL_TYPE_NUMERIC) {  boolean b = HSSFDateUtil.isCellDateFormatted(aCell);  if (b) {  Date date = aCell.getDateCellValue();  SimpleDateFormat df = new SimpleDateFormat(  "yyyy-MM-dd");  content.append(df.format(date));  }  }  }  }  }  response.getWriter().write(content.toString());    ppt：    BufferedInputStream bis = null;  URL url = null;  HttpURLConnection httpUrl = null; // 建立链接  url = new URL(urlReal);  httpUrl = (HttpURLConnection) url.openConnection();// 连接指定的资源  httpUrl.connect();// 获取网络输入流  bis = new BufferedInputStream(httpUrl.getInputStream());    StringBuffer content = new StringBuffer("");  SlideShow ss = new SlideShow(new HSLFSlideShow(bis));  Slide[] slides = ss.getSlides();  for (int i = 0; i < slides.length; i++) {  TextRun[] t = slides[i].getTextRuns();  for (int j = 0; j < t.length; j++) {  content.append(t[j].getText());  }  content.append(slides[i].getTitle());  }  response.getWriter().write(content.toString());    pdf：    BufferedInputStream bis = null;  URL url = null;  HttpURLConnection httpUrl = null; // 建立链接  url = new URL(urlReal);  httpUrl = (HttpURLConnection) url.openConnection();// 连接指定的资源  httpUrl.connect();// 获取网络输入流  bis = new BufferedInputStream(httpUrl.getInputStream());    PDDocument pdfdocument = null;  PDFParser parser = new PDFParser(bis);  parser.parse();  pdfdocument = parser.getPDDocument();  ByteArrayOutputStream out = new ByteArrayOutputStream();  OutputStreamWriter writer = new OutputStreamWriter(out);  PDFTextStripper stripper = new PDFTextStripper();  stripper.writeText(pdfdocument.getDocument(), writer);  writer.close();  byte[] contents = out.toByteArray();    String ts = new String(contents);  response.getWriter().write(ts);    txt：    BufferedReader bis = null;  URL url = null;  HttpURLConnection httpUrl = null; // 建立链接  url = new URL(urlReal);  httpUrl = (HttpURLConnection) url.openConnection();// 连接指定的资源  httpUrl.connect();// 获取网络输入流  bis = new BufferedReader( new InputStreamReader(httpUrl.getInputStream()));    StringBuffer buf=new StringBuffer();  String temp;  while ((temp = bis.readLine()) != null) {  buf.append(temp);  response.getWriter().write(temp);  if(buf.length()>=1000){  break;  }  }  bis.close();