Jsp + JCrop 上传头像预览并剪切

package com.myupload.util; import java.awt.Graphics; import java.awt.Image; import java.awt.image.BufferedImage; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import javax.imageio.ImageIO; /** * 图片工具类 */ public class ImageUtils { private ImageUtils(){} private BufferedImage image = null; public void load(File imageFile) throws IOException { image = ImageIO.read(imageFile); } public int getImageWidth() { return image.getWidth(); } public int getImageHeight() { return image.getHeight(); } //图片裁剪 public void cutTo(int x,int y,int tarWidth, int tarHeight) throws FileNotFoundException { if (image == null) { throw new FileNotFoundException( "image file not be load.please execute 'load' function agin."); } int iSrcWidth = getImageWidth(); // 得到源图宽 int iSrcHeight = getImageHeight(); // 得到源图长 // 如果源图片的宽度或高度小于目标图片的宽度或高度，则直接返回出错 if (iSrcWidth < tarWidth || iSrcHeight < tarHeight) { throw new RuntimeException("source image size too small."); } // 先求源图和目标图的尺寸比例 double dSrcScale = iSrcWidth * 1.0 / iSrcHeight; double dDstScale = tarWidth * 1.0 / tarHeight; // 先确定剪裁尺寸 int iDstLeft, iDstTop, iDstWidth, iDstHeight; if (dDstScale > dSrcScale) { // 目标图片宽 iDstWidth = iSrcWidth; iDstHeight = (int) (iDstWidth * 1.0 / dDstScale); } else { // 目标图片高 iDstHeight = iSrcHeight; iDstWidth = (int) (iDstHeight * dDstScale); } iDstLeft = (iSrcWidth - iDstWidth) / 2; iDstTop = (iSrcHeight - iDstHeight) / 2; // 剪裁 this.image = image .getSubimage(x, y, tarWidth, tarHeight); } /** * //图片缩放 不生成新的图片 */ public void zoomTo(int tarWidth, int tarHeight) { BufferedImage tagImage = new BufferedImage(tarWidth, tarHeight, BufferedImage.TYPE_INT_RGB); // 缩放图像 Image image = this.image.getScaledInstance(tarWidth, tarHeight, Image.SCALE_SMOOTH); Graphics g = tagImage.getGraphics(); g.drawImage(image, 0, 0, null); // 绘制目标图 g.dispose(); this.image = tagImage; } /** * 保存 * @param fileName * @param formatName * @throws IOException */ public void save(String fileName, String formatName) throws IOException { // 写文件 FileOutputStream out = null; try { ByteArrayOutputStream bos = new ByteArrayOutputStream(); ImageIO.write(this.image, formatName, bos);// 输出到bos out = new FileOutputStream(fileName); out.write(bos.toByteArray()); // 写文件 } catch (IOException e) { throw e; } finally { try { if (out != null) out.close(); } catch (IOException e) { e.printStackTrace(); } } } /** * //缩放图片 生成新的图片 */ public static boolean zoomImage(String srcFile, String dstFile, int width, int height, String formatName) { try { ImageUtils zoom = new ImageUtils(); zoom.load(new File(srcFile)); zoom.zoomTo(width, height); zoom.save(dstFile, formatName); } catch (IOException e) { e.printStackTrace(); return false; } return true; } private static ImageUtils fromImageFile(File file) throws IOException { ImageUtils utils = new ImageUtils(); utils.load(file); return utils; } /** * 加载图片 * @param fileName * @return * @throws IOException */ public static ImageUtils load(String fileName) throws IOException { File file = new File(fileName); return fromImageFile(file); } // public static void main(String[] args) { // String p = "e:/090613221071ed5df7cf2bce72.jpg"; // ImageUtils image , image2; // try { // image = ImageUtils.load(p); // //image.zoomImage(p, "e:/xxx.jpg", 500, 500, "jpg"); // image.zoomTo(500, 500); // image.cutTo(50,50,100, 100); // image.save("e:/111.jpg", "jpg"); // } catch (IOException e) { // e.printStackTrace(); // } // } }