图片压缩与格式转换

import java.awt.Image; import java.awt.image.BufferedImage; import java.awt.image.RenderedImage; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import javax.imageio.ImageIO; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; public class ImgUtil { private static ImgUtil imgUtil; public static ImgUtil getInstance(){ if(imgUtil==null){ imgUtil = new ImgUtil(); } return imgUtil; } public static void main(String args[]) { ImgUtil.getInstance().reduceImg("c:/aa.jpg", "c:/bb.png", 900,300); } public void reduceImg(String imgsrc, int widthdist, int heightdist) { reduceImg(imgsrc, imgsrc, widthdist, heightdist); } /** * 图像缩放 jpg格式 * @param imgsrc :原图片文件路径 * @param imgdist :生成的缩略图片文件路径 * @param widthdist :生成图片的宽度 * @param heightdist :生成图片的高度 */ public void reduceImg(String imgsrc, String imgdist, int widthdist, int heightdist) { try { File srcfile = new File(imgsrc); if (!srcfile.exists()) { return; } Image src = ImageIO.read(srcfile); BufferedImage tag = new BufferedImage((int) widthdist,(int) heightdist, BufferedImage.TYPE_INT_RGB); //Image.SCALE_SMOOTH 的缩略算法 生成缩略图片的平滑度的 优先级比速度高 生成的图片质量比较好 但速度慢 tag.getGraphics().drawImage(src.getScaledInstance(widthdist, heightdist,Image.SCALE_SMOOTH), 0, 0, null); FileOutputStream out = new FileOutputStream(imgdist); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); encoder.encode(tag); out.close(); // ImageIO.write(tag, "gif", new File(imgdist)); } catch (IOException ex) { ex.printStackTrace(); } } /** * 根据图片路径 读取图片文件 * @param fileName * @return */ private BufferedImage readImage(String fileName) { BufferedImage bi = null; try { bi = ImageIO.read(new File(fileName)); } catch (IOException ioe) { ioe.printStackTrace(); } return bi; } /** * 生成新的图片文件 * @param im * @param formatName * @param fileName * @return */ private boolean writeImage(RenderedImage im, String formatName, String fileName) { boolean result = false; try { result = ImageIO.write(im, formatName, new File(fileName)); } catch (IOException ioe) { ioe.printStackTrace(); } return result; } /** * 转换图片格式 到 jpg * @param im * @param fileName * @return */ private boolean writeJPEGImage(RenderedImage im, String fileName) { return writeImage(im, "JPEG", fileName); } /** * 转换图片格式 到 gif * @param im * @param fileName * @return */ private boolean writeGIFImage(RenderedImage im, String fileName) { return writeImage(im, "GIF", fileName); } private boolean writePNGImage(RenderedImage im, String fileName) { return writeImage(im, "PNG", fileName); } private boolean writeBMPImage(RenderedImage im, String fileName) { return writeImage(im, "BMP", fileName); } }