java在线预览txt、word、ppt、execel，pdf代码

 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();