截图方式预览文件
用户需求：文件在上传后，需要在页面展示类似windows平铺视图，这时候我们把文件保存一份截图，在平铺视图上展示截图即可。
第一步：安装OpenOffice http://www.openoffice.org/download/ 当然服务器和本地根据平台不同下载不同版本
第二步：启动OpenOffice服务(windows范例)：
cd C:\Program Files (x86)\OpenOffice 4\program soffice -headless -accept="socket,host=127.0.0.1,port=8100;urp;" -nofirststartwizard pause
转换工具类如下：
import java.awt.geom.AffineTransform; import java.awt.image.AffineTransformOp; import java.awt.image.BufferedImage; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.lang.reflect.Method; import java.security.AccessController; import java.security.PrivilegedAction; import java.util.Date; import java.util.Iterator; import javax.imageio.IIOImage; import javax.imageio.ImageIO; import javax.imageio.ImageWriter; import javax.imageio.stream.ImageOutputStream; import org.icepdf.core.pobjects.Document; import org.icepdf.core.pobjects.Page; import org.icepdf.core.util.GraphicsRenderingHints; import com.artofsolving.jodconverter.DocumentConverter; import com.artofsolving.jodconverter.openoffice.connection.OpenOfficeConnection; import com.artofsolving.jodconverter.openoffice.connection.SocketOpenOfficeConnection; import com.artofsolving.jodconverter.openoffice.converter.OpenOfficeDocumentConverter; @SuppressWarnings("all") public class FileConvertUtil { private static final String[] OFFICE = new String[] { ".doc", ".docx", ".docx", ".ppt", ".pptx", ".xls", ".xlsx" }; private static final String[] IMG = new String[] { ".bmp", ".gif", ".jpg", ".tif", ".png" }; private static final String PDF = ".pdf"; private static final String TXT = ".txt"; public static final String FILETYPE_JPG = "jpg"; public static final String SUFF_IMAGE = "." + FILETYPE_JPG; /** * 根据源文件生成一个预览图片 * * @param inputFilePath 文件路径 * @param suffix 文件后缀 * @return * @throws Exception */ public static int convert(String inputFilePath, String suffix) throws Exception { int num = 0; if (PDF.equals(suffix)) { num = pdf2Jpg(inputFilePath); } if (TXT.equals(suffix)) { num = txt2pdf(inputFilePath); } for (String sf : OFFICE) { if (sf.equals(suffix)) { num = Office2pdf(inputFilePath); break; } } for (String sf : IMG) { if (sf.equals(suffix)) { num = 1; ImgConvert imgConvert = new ImgConvert(); imgConvert.convert(inputFilePath, "102x102", 102, 120); imgConvert.convert(inputFilePath, "560x600", 560, 600); break; } } return num; } /** * docx, .xls, .xlsx, .ppt, .pptx筿 * * @param inputFilePath */ public static int txt2pdf(String inputFilePath) { int num = 0; try { OpenOfficeConnection connection = new SocketOpenOfficeConnection("127.0.0.1", 8100); connection.connect(); DocumentConverter converter = new OpenOfficeDocumentConverter(connection); String outputFilePath = getOutputFilePath(inputFilePath); File inputFile = new File(inputFilePath); inputFile = FileReName(inputFile, ".odt"); if (inputFile.exists()) { File outputFile = new File(outputFilePath); if (!outputFile.getParentFile().exists()) { outputFile.getParentFile().mkdirs(); } converter.convert(inputFile, outputFile); } connection.disconnect(); num = pdf2Jpg(outputFilePath); } catch (IOException e) { e.printStackTrace(); } return num; } public static File FileReName(File file, String suffix) { String fileName = "/" + file.getName(); String target = file.getParent() + fileName.substring(0, fileName.lastIndexOf(".")) + suffix; File file2 = new File(target); file.renameTo(file2); return file2; } /** * docx, .xls, .xlsx, .ppt, .pptx筿 * * @param inputFilePath */ public static int Office2pdf(String inputFilePath) { int num = 0; try { long l=new Date().getTime(); OpenOfficeConnection connection = new SocketOpenOfficeConnection("127.0.0.1", 8100); connection.connect(); DocumentConverter converter = new OpenOfficeDocumentConverter(connection); String outputFilePath = getOutputFilePath(inputFilePath); File inputFile = new File(inputFilePath); if (inputFile.exists()) { File outputFile = new File(outputFilePath); if (!outputFile.getParentFile().exists()) { outputFile.getParentFile().mkdirs(); } converter.convert(inputFile, outputFile); } connection.disconnect(); num = pdf2Jpg(outputFilePath); } catch (IOException e) { e.printStackTrace(); } return num; } public static String getOutputFilePath(String inputFilePath) { String outputFilePath = inputFilePath.substring(0, inputFilePath.lastIndexOf(".")) + ".pdf"; return outputFilePath; } /** * * 清空缓冲 * * @param buffer */ public static void unmap(final Object buffer) { AccessController.doPrivileged(new PrivilegedAction() { public Object run() { try { Method getCleanerMethod = buffer.getClass().getMethod("cleaner", new Class[0]); getCleanerMethod.setAccessible(true); sun.misc.Cleaner cleaner = (sun.misc.Cleaner) getCleanerMethod.invoke(buffer, new Object[0]); cleaner.clean(); } catch (Exception e) { e.printStackTrace(); } return null; } }); } public static void toThumbnail(String filePath){ BufferedImage bis = null; try { File fi = new File(filePath+".jpg"); //大图文件 File fo = new File(filePath+"102x102.jpg"); //将要转换出的小图文件 AffineTransform transform = new AffineTransform(); bis = ImageIO.read(fi); int w = bis.getWidth(); int h = bis.getHeight(); double scale = (double)w/h; int nw = 102; int nh = (nw * h) / w; if(nh>102) { nh = 102; nw = (nh * w) / h; } double sx = (double)nw / w; double sy = (double)nh / h; transform.setToScale(sx,sy); AffineTransformOp ato = new AffineTransformOp(transform, null); BufferedImage bid = new BufferedImage(nw, nh, BufferedImage.TYPE_3BYTE_BGR); ato.filter(bis,bid); ImageIO.write(bid, "jpg", fo); } catch(Exception e) { e.printStackTrace(); } finally{ } } /** * * @param inputFilePath * @return */ public static int pdf2Jpg(String inputFilePath) { int maxPages =0; try{ Document document = null; float rotation = 0f; String imagepath = inputFilePath.replaceAll(".pdf", ".jpg"); document = new Document(); document.setFile(inputFilePath); maxPages = document.getPageTree().getNumberOfPages(); System.out.println(maxPages); BufferedImage img = (BufferedImage) document.getPageImage(0, GraphicsRenderingHints.SCREEN, Page.BOUNDARY_CROPBOX, rotation,1); Iterator iter = ImageIO.getImageWritersBySuffix(FILETYPE_JPG); ImageWriter writer = (ImageWriter) iter.next(); File outFile = new File(imagepath); FileOutputStream out = new FileOutputStream(outFile); ImageOutputStream outImage = ImageIO.createImageOutputStream(out); writer.setOutput(outImage); writer.write(new IIOImage(img, null, null)); toThumbnail(imagepath.substring(0,imagepath.lastIndexOf(".jpg"))); } catch (Exception e) { e.printStackTrace(); } return maxPages; } public static void main(String[] args) { pdf2Jpg("E:/111.pdf"); } }
图片处理工具类：
import java.awt.image.BufferedImage; import java.io.File; import javax.imageio.ImageIO; public class ImgConvert { private int width; private int height; private int scaleWidth; double support = (double) 3.0; double PI = (double) 3.14159265358978; double[] contrib; double[] normContrib; double[] tmpContrib; int startContrib, stopContrib; int nDots; int nHalfDots; //fromFileStr原图片地坿,saveToFileStr生成缩略图地坿,formatWideth生成图片宽度,formatHeight高度 public void convert(String fromFileStr, String suffix, int formatWideth, int formatHeight) throws Exception { BufferedImage srcImage; int x = fromFileStr.lastIndexOf("."); int l = fromFileStr.length(); String extName = fromFileStr.substring(x, l); String filename = fromFileStr.substring(0, x); File saveFile = new File(filename + suffix + extName); File fromFile = new File(fromFileStr); srcImage = javax.imageio.ImageIO.read(fromFile); // construct image int imageWideth = srcImage.getWidth(null); int imageHeight = srcImage.getHeight(null); int changeToWideth = 0; int changeToHeight = 0; if (imageWideth > 0 && imageHeight > 0) { if (imageWideth / imageHeight >= formatWideth / formatHeight) { if (imageWideth > formatWideth) { changeToWideth = formatWideth; changeToHeight = (imageHeight * formatWideth) / imageWideth; } else { changeToWideth = imageWideth; changeToHeight = imageHeight; } } else { if (imageHeight > formatHeight) { changeToHeight = formatHeight; changeToWideth = (imageWideth * formatHeight) / imageHeight; } else { changeToWideth = imageWideth; changeToHeight = imageHeight; } } } srcImage = imageZoomOut(srcImage, changeToWideth, changeToHeight); ImageIO.write(srcImage, "JPEG", saveFile); } public BufferedImage imageZoomOut(BufferedImage srcBufferImage, int w, int h) { width = srcBufferImage.getWidth(); height = srcBufferImage.getHeight(); scaleWidth = w; if (DetermineResultSize(w, h) == 1) { return srcBufferImage; } CalContrib(); BufferedImage pbOut = HorizontalFiltering(srcBufferImage, w); BufferedImage pbFinalOut = VerticalFiltering(pbOut, h); return pbFinalOut; } private int DetermineResultSize(int w, int h) { double scaleH, scaleV; scaleH = (double) w / (double) width; scaleV = (double) h / (double) height; if (scaleH >= 1.0 && scaleV >= 1.0) { return 1; } return 0; } private double Lanczos(int i, int inWidth, int outWidth, double Support) { double x; x = (double) i * (double) outWidth / (double) inWidth; return Math.sin(x * PI) / (x * PI) * Math.sin(x * PI / Support) / (x * PI / Support); } private void CalContrib() { nHalfDots = (int) ((double) width * support / (double) scaleWidth); nDots = nHalfDots * 2 + 1; try { contrib = new double[nDots]; normContrib = new double[nDots]; tmpContrib = new double[nDots]; } catch (Exception e) { e.printStackTrace(); //System.out.println("init contrib,normContrib,tmpContrib" + e); } int center = nHalfDots; contrib[center] = 1.0; double weight = 0.0; int i = 0; for (i = 1; i <= center; i++) { contrib[center + i] = Lanczos(i, width, scaleWidth, support); weight += contrib[center + i]; } for (i = center - 1; i >= 0; i--) { contrib[i] = contrib[center * 2 - i]; } weight = weight * 2 + 1.0; for (i = 0; i <= center; i++) { normContrib[i] = contrib[i] / weight; } for (i = center + 1; i < nDots; i++) { normContrib[i] = normContrib[center * 2 - i]; } } private void CalTempContrib(int start, int stop) { double weight = 0; int i = 0; for (i = start; i <= stop; i++) { weight += contrib[i]; } for (i = start; i <= stop; i++) { tmpContrib[i] = contrib[i] / weight; } } private int GetRedValue(int rgbValue) { int temp = rgbValue & 0x00ff0000; return temp >> 16; } private int GetGreenValue(int rgbValue) { int temp = rgbValue & 0x0000ff00; return temp >> 8; } private int GetBlueValue(int rgbValue) { return rgbValue & 0x000000ff; } private int ComRGB(int redValue, int greenValue, int blueValue) { return (redValue << 16) + (greenValue << 8) + blueValue; } private int HorizontalFilter(BufferedImage bufImg, int startX, int stopX, int start, int stop, int y, double[] pContrib) { double valueRed = 0.0; double valueGreen = 0.0; double valueBlue = 0.0; int valueRGB = 0; int i, j; for (i = startX, j = start; i <= stopX; i++, j++) { valueRGB = bufImg.getRGB(i, y); valueRed += GetRedValue(valueRGB) * pContrib[j]; valueGreen += GetGreenValue(valueRGB) * pContrib[j]; valueBlue += GetBlueValue(valueRGB) * pContrib[j]; } valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen), Clip((int) valueBlue)); return valueRGB; } private BufferedImage HorizontalFiltering(BufferedImage bufImage, int iOutW) { int dwInW = bufImage.getWidth(); int dwInH = bufImage.getHeight(); int value = 0; BufferedImage pbOut = new BufferedImage(iOutW, dwInH, BufferedImage.TYPE_INT_RGB); for (int x = 0; x < iOutW; x++) { int startX; int start; int X = (int) (((double) x) * ((double) dwInW) / ((double) iOutW) + 0.5); int y = 0; startX = X - nHalfDots; if (startX < 0) { startX = 0; start = nHalfDots - X; } else { start = 0; } int stop; int stopX = X + nHalfDots; if (stopX > (dwInW - 1)) { stopX = dwInW - 1; stop = nHalfDots + (dwInW - 1 - X); } else { stop = nHalfDots * 2; } if (start > 0 || stop < nDots - 1) { CalTempContrib(start, stop); for (y = 0; y < dwInH; y++) { value = HorizontalFilter(bufImage, startX, stopX, start, stop, y, tmpContrib); pbOut.setRGB(x, y, value); } } else { for (y = 0; y < dwInH; y++) { value = HorizontalFilter(bufImage, startX, stopX, start, stop, y, normContrib); pbOut.setRGB(x, y, value); } } } return pbOut; } private int VerticalFilter(BufferedImage pbInImage, int startY, int stopY, int start, int stop, int x, double[] pContrib) { double valueRed = 0.0; double valueGreen = 0.0; double valueBlue = 0.0; int valueRGB = 0; int i, j; for (i = startY, j = start; i <= stopY; i++, j++) { valueRGB = pbInImage.getRGB(x, i); valueRed += GetRedValue(valueRGB) * pContrib[j]; valueGreen += GetGreenValue(valueRGB) * pContrib[j]; valueBlue += GetBlueValue(valueRGB) * pContrib[j]; } valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen), Clip((int) valueBlue)); return valueRGB; } private BufferedImage VerticalFiltering(BufferedImage pbImage, int iOutH) { int iW = pbImage.getWidth(); int iH = pbImage.getHeight(); int value = 0; BufferedImage pbOut = new BufferedImage(iW, iOutH, BufferedImage.TYPE_INT_RGB); for (int y = 0; y < iOutH; y++) { int startY; int start; int Y = (int) (((double) y) * ((double) iH) / ((double) iOutH) + 0.5); startY = Y - nHalfDots; if (startY < 0) { startY = 0; start = nHalfDots - Y; } else { start = 0; } int stop; int stopY = Y + nHalfDots; if (stopY > (int) (iH - 1)) { stopY = iH - 1; stop = nHalfDots + (iH - 1 - Y); } else { stop = nHalfDots * 2; } if (start > 0 || stop < nDots - 1) { CalTempContrib(start, stop); for (int x = 0; x < iW; x++) { value = VerticalFilter(pbImage, startY, stopY, start, stop, x, tmpContrib); pbOut.setRGB(x, y, value); } } else { for (int x = 0; x < iW; x++) { value = VerticalFilter(pbImage, startY, stopY, start, stop, x, normContrib); pbOut.setRGB(x, y, value); } } } return pbOut; } int Clip(int x) { if (x < 0) return 0; if (x > 255) return 255; return x; } }