图片切图

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ImageUtil {
 private static final Log logger = LogFactory.getLog(ImageUtil.class);

 public ImageUtil() {
 }

 public static void reduceImg(String imgsrc, String imgdist, int widthdist,
   int heightdist) {
  try {
   File srcfile = new File(imgsrc);
   if (!srcfile.exists()) {
    return;
   }
   Image src = javax.imageio.ImageIO.read(srcfile);
   int width = src.getWidth(null);
   int height = src.getHeight(null);

   if (width <= widthdist && height <= heightdist) {
    FileUtil.copyFileTo(new File(imgsrc), imgdist);
    return;
   }

   float wh = (float) width / (float) height;

   if (wh > 1) {
    float tmp_heigth = (float) widthdist / wh;
    BufferedImage tag = new BufferedImage(widthdist,
      (int) tmp_heigth, BufferedImage.TYPE_INT_RGB);
    tag.getGraphics().drawImage(src, 0, 0, widthdist,
      (int) tmp_heigth, null);
    String distFilePath = FileUtil.getFileNameVerifyExists(imgdist);
    FileUtil.makeDirectory(distFilePath);
    FileOutputStream out = new FileOutputStream(imgdist);
    JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);

    JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(tag);
    param.setQuality(.85F, false);
    encoder.setJPEGEncodeParam(param);

    encoder.encode(tag);
    out.close();
   } else {
    if (width <= widthdist && wh > 0.1f) {
     // FileUtils.copyFile(new File(imgsrc), new File(imgdist));
     FileUtil.copyFileTo(new File(imgsrc), imgdist);
     return;
    }
    if (width > widthdist && wh > 0.1f) {
     float tmp_heigth = (float) widthdist / wh;
     BufferedImage tag = new BufferedImage(widthdist,
       (int) tmp_heigth, BufferedImage.TYPE_INT_RGB);
     tag.getGraphics().drawImage(src, 0, 0, widthdist,
       (int) tmp_heigth, null);
     String distFilePath = FileUtil
       .getFileNameVerifyExists(imgdist);
     FileUtil.makeDirectory(distFilePath);
     FileOutputStream out = new FileOutputStream(imgdist);
     JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);

     JPEGEncodeParam param = encoder
       .getDefaultJPEGEncodeParam(tag);
     param.setQuality(.85F, false);
     encoder.setJPEGEncodeParam(param);

     encoder.encode(tag);
     out.close();
     return;
    }

    float tmp_width = (float) heightdist * wh;
    BufferedImage tag = new BufferedImage((int) tmp_width,
      heightdist, BufferedImage.TYPE_INT_RGB);
    tag.getGraphics().drawImage(src, 0, 0, (int) tmp_width,
      heightdist, null);
    String distFilePath = FileUtil.getFileNameVerifyExists(imgdist);
    FileUtil.makeDirectory(distFilePath);
    FileOutputStream out = new FileOutputStream(imgdist);
    JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);

    JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(tag);
    param.setQuality(.85F, false);
    encoder.setJPEGEncodeParam(param);

    encoder.encode(tag);
    out.close();
   }
  } catch (IOException ex) {
   logger.error(ex);
  }
 }

 public static void createThumb(String srcImagePath, String distImagePath,
   int width, int height) {
  // String dir = FileService.createDynanmicalDir(saveThumbBasePath,
  // StringUtil.getRandom());
  // String location = "/" + dir + "/" + fileName;
  String imgdist = distImagePath;
  String imgsrc = srcImagePath;
  reduceImg(imgsrc, imgdist, width, height);
 }

 public static void main(String[] args) {
  reduceImg("d:\\DSC04272.JPG","d:\\00000002.jpg",100,100);
 }
}