任意格式图片生成缩略图.doc

该文档所编写的JAVA类，用于生成各种格式图片的缩略图。import java.awt.Image;import java.awt.Graphics2D;import java.awt.geom.AffineTransform;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.OutputStream;import java.io.FileOutputStream;import javax.swing.ImageIcon;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder;import java.io.FileNotFoundException;import java.awt.Toolkit;import java.io.BufferedOutputStream;import com.sun.image.codec.jpeg.JPEGEncodeParam;import java.awt.image.MemoryImageSource;import java.io.FileInputStream;import cn.js.fan.util.StrUtil;public class Thumbnail /* * Reads an image in a file and creates * a thumbnail in another file. * param orig The name of image file. * param thumb The name of thumbnail file. * Will be created if necessary. * param maxDim The width and height of * the thumbnail must * be maxDim pixels or less. */ public static void createThumbnail( String srcPath, String thumbPath, int maxDim) try / Get the image from a file. if (srcPath.toLowerCase().endsWith(.bmp) inImage = getBMPImage(srcPath); else inImage = new ImageIcon( srcPath).getImage(); / Determine the scale. double scale = (double) maxDim / ( double) inImage.getHeight(null); if (inImage.getWidth( null) inImage.getHeight(null) scale = (double) maxDim / ( double) inImage.getWidth(null); / Determine size of new image. /One of them / should equal maxDim. int scaledW = (int) ( scale * inImage.getWidth(null); int scaledH = (int) ( scale * inImage.getHeight(null); / Create an image buffer in /which to paint on. BufferedImage outImage = new BufferedImage(scaledW, scaledH, BufferedImage.TYPE_INT_RGB); / Set the scale. AffineTransform tx = new AffineTransform(); / If the image is smaller than / the desired image size, / dont bother scaling. if (scale 1.0d) tx.scale(scale, scale); / Paint image. Graphics2D g2d = outImage.createGraphics(); g2d.drawImage(inImage, tx, null); g2d.dispose(); / JPEG-encode the image /and write to file. OutputStream os = new FileOutputStream(thumbPath); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os); encoder.encode(outImage); os.close(); catch (IOException e) e.printStackTrace(); /* * 根据限定的宽度生成缩略图(会生成黑色背景) * param srcPath String * param thumbPath String * param widthDim int */ public static void createThumbnailLimitWidth( String srcPath, String thumbPath, int widthDim) try / Get the image from a file. Image inImage = null; if (srcPath.toLowerCase().endsWith(.bmp) inImage = getBMPImage(srcPath); else inImage = new ImageIcon( srcPath).getImage(); / Determine the scale. double scale = (double) widthDim / (double) inImage.getWidth(null); / Determine size of new image. /One of them / should equal maxDim. int scaledW = (int) ( scale * inImage.getWidth(null); int scaledH = (int) ( scale * inImage.getHeight(null); / Create an image buffer in / which to paint on. BufferedImage outImage = new BufferedImage(scaledW, scaledH, BufferedImage.TYPE_INT_RGB); / Set the scale. AffineTransform tx = new AffineTransform(); / If the image is smaller than / the desired image size, / dont bother scaling. / if (scale 1.0d) tx.scale(scale, scale); / / Paint image. Graphics2D g2d = outImage.createGraphics(); g2d.drawImage(inImage, tx, null); g2d.dispose(); / JPEG-encode the image /and write to file. OutputStream os = new FileOutputStream(thumbPath); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os); encoder.encode(outImage); os.close(); catch (IOException e) e.printStackTrace(); /* * 读取BMP图片 * param source String */ private static Image getBMPImage(String source) throws Exception FileInputStream fs = null; Image image = null; try fs = new FileInputStream(source); int bfLen = 14; byte bf = new bytebfLen; fs.read(bf, 0, bfLen); / 读取14字节BMP文件头 int biLen = 40; byte bi = new bytebiLen; fs.read(bi, 0, biLen); / 读取40字节BMP信息头 / 源图宽度 int nWidth = (int) bi7 & 0xff) 24) | (int) bi6 & 0xff) 16) | (int) bi5 & 0xff) 8) | (int) bi4 & 0xff; / 源图高度 int nHeight = (int) bi11 & 0xff) 24) | (int) bi10 & 0xff) 16) | (int) bi9 & 0xff) 8) | (int) bi8 & 0xff; / 位数 int nBitCount = (int) bi15 & 0xff) 8) | (int) bi14 & 0xff; / 源图大小 int nSizeImage = (int) bi23 & 0xff) 24) | (int) bi22 & 0xff) 16) | (int) bi21 & 0xff) 8) | (int) bi20 & 0xff; / 对24位BMP进行解析 if (nBitCount = 24) int nPad = (nSizeImage / nHeight) - nWidth * 3; int nData = new intnHeight * nWidth; byte bRGB = new byte(nWidth + nPad) * 3 * nHeight; fs.read(bRGB, 0, (nWidth + nPad) * 3 * nHeight); int nIndex = 0; for (int j = 0; j nHeight; j+) for (int i = 0; i nWidth; i+) nDatanWidth * (nHeight - j - 1) + i = (255 & 0xff) 24 | (int) bRGBnIndex + 2 & 0xff) 16) | (int) bRGBnIndex + 1 & 0xff) 8) | (int) bRGBnIndex & 0xff; nIndex += 3; nIndex += nPad; Toolkit kit = T