java生成高质量缩略图的代码实现，java缩略图,java生成高质量缩略图

java生成高质量缩略图的代码实现，java缩略图,java生成高质量缩略图

java生成高质量缩略图的代码实现

import java.awt.Image;import java.awt.Toolkit;import java.awt.image.BufferedImage;import java.awt.image.MemoryImageSource;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import javax.imageio.ImageIO;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder;/** *//** * @将文件转化为缩略图 * */public class jpgThumbnail {    private static final String BMP = "bmp";    private static final String PNG = "png";    private static final String GIF = "gif";    private static final String JPEG = "jpeg";    private static final String JPG = "jpg";    public static void getThumbnail(            String source,            String output,            int width,            int height) {        boolean adjustSize=true;        if (source == null || source.equals("") || width < 1 || height < 1) {            return;        }        if(output==null || output.equals(""))        {            return;        }        source = source.toLowerCase();        if (source.endsWith(BMP)) {            BMPThumbnailHandler(source, output,width, height, adjustSize);        } else if (source.endsWith(PNG) || source.endsWith(GIF)                || source.endsWith(JPEG) || source.endsWith(JPG)) {            thumbnailHandler(source, output,width, height, adjustSize);        }    }    private static void thumbnailHandler(            String source,            String output,            int width,            int height,            boolean adjustSize) {        try {            File sourceFile = new File(source);            if (sourceFile.exists()) {                Image image = ImageIO.read(sourceFile);                int theImgWidth = image.getWidth(null);                int theImgHeight = image.getHeight(null);                int[] size = { theImgWidth, theImgHeight };                if (adjustSize) {                    size = adjustImageSize(theImgWidth, theImgHeight, width,height);                }                StringBuffer thumbnailFile=new StringBuffer();                //thumbnailFile.append(sourceFile.getParent());                //thumbnailFile.append(File.separatorChar);                thumbnailFile.append(output);                writeFile(image, size[0], size[1], thumbnailFile.toString());            }        } catch (Exception e) {            e.printStackTrace();            return;        }    }    private static void BMPThumbnailHandler(            String source,            String output,            int width,            int height,            boolean adjustSize) {        try {            File sourceFile = new File(source);            if (sourceFile.exists()) {                Image image = getBMPImage(source);                int theImgWidth = image.getWidth(null);                int theImgHeight = image.getHeight(null);                int[] size = { theImgWidth, theImgHeight };                if (adjustSize) {                    size = adjustImageSize(theImgWidth, theImgHeight, width, height);                }                StringBuffer thumbnailFile=new StringBuffer();                //thumbnailFile.append(sourceFile.getParent());                //thumbnailFile.append(File.separatorChar);                thumbnailFile.append(output);                writeFile(image, size[0], size[1], thumbnailFile.toString());            }        } catch (Exception e) {            e.printStackTrace();            return;        }    }    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 byte[bfLen];            fs.read(bf, 0, bfLen); // 读取14字节BMP文件头            int biLen = 40;            byte bi[] = new byte[biLen];            fs.read(bi, 0, biLen); // 读取40字节BMP信息头            // 源图宽度            int nWidth = (((int) bi[7] & 0xff) << 24)                    | (((int) bi[6] & 0xff) << 16)                    | (((int) bi[5] & 0xff) << 8) | (int) bi[4] & 0xff;            // 源图高度            int nHeight = (((int) bi[11] & 0xff) << 24)                    | (((int) bi[10] & 0xff) << 16)                    | (((int) bi[9] & 0xff) << 8) | (int) bi[8] & 0xff;            // 位数            int nBitCount = (((int) bi[15] & 0xff) << 8) | (int) bi[14] & 0xff;            // 源图大小            int nSizeImage = (((int) bi[23] & 0xff) << 24)                    | (((int) bi[22] & 0xff) << 16)                    | (((int) bi[21] & 0xff) << 8) | (int) bi[20] & 0xff;            // 对24位BMP进行解析            if (nBitCount == 24) {                int nPad = (nSizeImage / nHeight) - nWidth * 3;                int nData[] = new int[nHeight * 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++) {                        nData[nWidth * (nHeight - j - 1) + i] = (255 & 0xff) << 24                                | (((int) bRGB[nIndex + 2] & 0xff) << 16)                                | (((int) bRGB[nIndex + 1] & 0xff) << 8)                                | (int) bRGB[nIndex] & 0xff;                        nIndex += 3;                    }                    nIndex += nPad;                }                Toolkit kit = Toolkit.getDefaultToolkit();                image = kit.createImage(new MemoryImageSource(nWidth, nHeight,                        nData, 0, nWidth));            }        } catch (Exception e) {            e.printStackTrace();            throw new Exception(e);        } finally {            if (fs != null) {                fs.close();            }        }        return image;    }    private static void writeFile(            Image image,            int width,            int height,            String thumbnailFile) throws Exception {        if (image == null) return;        BufferedImage tag = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);        tag.getGraphics().drawImage(image, 0, 0, width, height, null);        FileOutputStream out = null;        try {            out = new FileOutputStream(thumbnailFile);            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);            encoder.encode(tag);        } catch (Exception e) {            e.printStackTrace();            throw new Exception(e);        } finally {            if (out != null) {                out.close();            }        }    }    private static int[] adjustImageSize(int theImgWidth, int theImgHeight,            int defWidth, int defHeight) {                int[] size = { 0, 0 };        float theImgHeightFloat=Float.parseFloat(String.valueOf(theImgHeight));        float theImgWidthFloat=Float.parseFloat(String.valueOf(theImgWidth));        if (theImgWidth<theImgHeight){            float scale=theImgHeightFloat/theImgWidthFloat;            size[0]=Math.round(defHeight/scale);            size[1]=defHeight;        }else{            float scale=theImgWidthFloat/theImgHeightFloat;            size[0]=defWidth;            size[1]=Math.round(defWidth/scale);        }        return size;    }    public static void main(String[] agrs) {        //zoomPicture("E:\\1.jpg","E:\\test.jpg",60, 80);        getThumbnail("E:\\1.jpg","E:\\test.jpg",60, 80);    }}