小图生成

import javax.imageio.ImageIO; import java.awt.image.BufferedImage; import java.awt.image.ColorModel; import java.awt.image.WritableRaster; import java.awt.*; import java.awt.geom.AffineTransform; import java.io.InputStream; import java.io.File; import java.io.FileOutputStream; public class XiaoTu { public static BufferedImage resize(BufferedImage source, int targetW, int targetH) { // targetW，targetH分别表示目标长和宽 int type = source.getType(); BufferedImage target = null; double sx = (double) targetW / source.getWidth(); double sy = (double) targetH / source.getHeight(); // 这里想实现在targetW，targetH范围内实现等比缩放。如果不需要等比缩放 // 则将下面的if else语句注释即可 if (sx > sy) { sx = sy; targetW = (int) (sx * source.getWidth()); } else { sy = sx; targetH = (int) (sy * source.getHeight()); } if (type == BufferedImage.TYPE_CUSTOM) { // handmade ColorModel cm = source.getColorModel(); WritableRaster raster = cm.createCompatibleWritableRaster(targetW, targetH); boolean alphaPremultiplied = cm.isAlphaPremultiplied(); target = new BufferedImage(cm, raster, alphaPremultiplied, null); } else target = new BufferedImage(targetW, targetH, type); Graphics2D g = target.createGraphics(); // smoother than exlax: g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy)); g.dispose(); return target; } public static void saveImageAsJpg(String fromFileStr, String saveToFileStr, int width, int hight) throws Exception { BufferedImage srcImage; // String ex = // fromFileStr.substring(fromFileStr.indexOf("."),fromFileStr.length()); String imgType = "JPEG"; if (fromFileStr.toLowerCase().endsWith(".png")) { imgType = "PNG"; } // System.out.println(ex); File saveFile = new File(saveToFileStr); File fromFile = new File(fromFileStr); srcImage = ImageIO.read(fromFile); if (width > 0 || hight > 0) { srcImage = resize(srcImage, width, hight); } ImageIO.write(srcImage, imgType, saveFile); } public static void main(String argv[]) { try { // 参数1(from),参数2(to),参数3(宽),参数4(高) XiaoTu.saveImageAsJpg("D:/piii/SDC10792.JPG", "c:/6.gif", 800, 600); } catch (Exception e) { e.printStackTrace(); } } }