Java上传图片，对图片进行等比例缩放，及局部裁剪的工具类代码详解编程语言

import java.awt.Container; 
import java.awt.Graphics; 
import java.awt.Graphics2D; 
import java.awt.Image; 
import java.awt.MediaTracker; 
import java.awt.Rectangle; 
import java.awt.RenderingHints; 
import java.awt.Toolkit; 
import java.awt.image.BufferedImage; 
import java.awt.image.CropImageFilter; 
import java.awt.image.FilteredImageSource; 
import java.awt.image.ImageFilter; 
import java.io.BufferedInputStream; 
import java.io.BufferedOutputStream; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.util.UUID; 
  
import javax.imageio.ImageIO; 
  
  
import com.sun.image.codec.jpeg.JPEGCodec; 
import com.sun.image.codec.jpeg.JPEGEncodeParam; 
import com.sun.image.codec.jpeg.JPEGImageEncoder; 
  
public class FileUploadUtils { 
      
    /** 
     * 裁剪图片  
     * @param input 
     * @param basepath 
     * @param uid 
     * @param x 
     * @param y 
     * @param width 
     * @param height 
     * @return 绝对路径 
     * @throws IOException  
     */ 
    public static String cutImg(String input,String basepath,int x,int y,int width,int height) throws IOException{ 
        String path2 = basepath+"/"+ConstantUtils.USERFACETEMPPATH; 
        String postfix = getPostfix(input); 
        String dst = path2 +"/"+UUID.randomUUID().toString()+"."+postfix; 
          
        createDir(path2); 
        imgCut(basepath+input,dst,postfix,x,y,width,height); 
          
        return dst; 
    } 
      
    /** 
     * 裁剪图片 
     * @param input 
     * @param src 
     * @param x 
     * @param y 
     * @param width 
     * @param height 
     * @throws IOException 
     */ 
    public static void imgCut(String input,String dst,String type,int x,int y,int width,int height) throws IOException 
     { 
            BufferedImage fromimg = ImageIO.read(new File(input)); 
            ImageFilter cropFilter = new CropImageFilter(x,y,width,height);    
            Image img = Toolkit.getDefaultToolkit().createImage(new FilteredImageSource(fromimg.getSource(), cropFilter)); 
            BufferedImage tag = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);   
              
            Graphics g = tag.getGraphics();    
            g.drawImage(img, 0, 0, null); // 绘制小图    
           g.dispose();    
            // 输出为文件    
           // dir = "d://temp//cut_image_" + i + "_" + j + ".jpg";    
            File f = new File(dst);    
            ImageIO.write(tag,type, f);   
              
        } 
  
  
    /** 
     * 上传头像文件 
     * @param src 
     * @param basepath 
     * @param filename 
     * @return 
     * @throws Exception 
     */ 
    public static String uploadImg(File src,String basepath,String filename) throws Exception{ 
        String daypath = DateTools.getYear() + "" + DateTools.getMonth() + "" + DateTools.getMonthWeek(); 
          
        String temppath = ConstantUtils.BASEUPLOADPATH+"/"+ConstantUtils.ORIGINALIMGPATH+"/" + daypath; 
        String thumbnailpath = ConstantUtils.BASEUPLOADPATH+"/"+ConstantUtils.THUMBNAILIMGPATH+"/" + daypath; 
          
        String postfix = getPostfix(filename); 
        String uuid = UUID.randomUUID().toString(); 
        String dsttempname = uuid+"."+postfix; 
          
        createDir(basepath +"/"+temppath); 
        createDir (basepath +"/"+ thumbnailpath); 
          
          
        String dstallpath = basepath +"/"+temppath+"/"+dsttempname; 
        String dstthumbnailpath = basepath +"/"+thumbnailpath+"/"+dsttempname; 
          
        copy(src,new File(dstallpath)); 
  
        //对上传的文件进行 等比例 裁剪。  按照前段要展现的  height width 
        Thumbnail(dstallpath,dstthumbnailpath,350,300,100); 
          
        //返回裁剪后的路径  
          
        return thumbnailpath+"/"+dsttempname; 
    } 
      
    /** 
     * 上传文件 
     * @param src 
     * @param dst 
     * @throws Exception 
     */ 
    public static void copy(File src, File dst) throws Exception { 
        try { 
            InputStream in = null; 
            OutputStream out = null; 
            try { 
                in = new BufferedInputStream(new FileInputStream(src), ConstantUtils.BUFFER_SIZE); 
                out = new BufferedOutputStream(new FileOutputStream(dst), ConstantUtils.BUFFER_SIZE); 
                byte[] buffer = new byte[ConstantUtils.BUFFER_SIZE]; 
                while (in.read(buffer) > 0) { 
                    out.write(buffer); 
                } 
            } finally { 
                if (null != in) { 
                    in.close(); 
                } 
                if (null != out) { 
                    out.close(); 
                } 
            } 
        } catch (Exception e) { 
            e.printStackTrace(); 
            throw e; 
        } 
    } 
      
    /** 
     * 得到文件后缀  jpg   
     * @param fileName 
     * @return 
     */ 
    public static String getPostfix(String fileName){ 
        if (fileName.equals("")) 
            return ""; 
        int pos = fileName.lastIndexOf("."); 
        if (pos < 0) { 
            return fileName.substring(fileName.length() - 3).toLowerCase(); 
        } else { 
            return fileName.substring(pos+1).toLowerCase(); 
        } 
    } 
      
    /** 
     * 创建目录 
     * @param filePath 
     */ 
    public static void createDir(String filePath) { 
        File myFile = new File(filePath); 
        if (!myFile.exists()) { 
            if (!myFile.mkdirs()) 
                System.out.println("创建目录 fail"); 
            else 
                System.out.println("创建目录 success"); 
        } 
        myFile = null; 
    } 
      
    /** 
     * 等比例缩放图片 
     * @param infile 
     * @param outfile 
     * @param width 
     * @param height 
     * @param quality 
     * @throws IOException 
     * @throws InterruptedException 
     */ 
    public static void Thumbnail(String infile, String outfile, int width, int height, int quality) throws IOException, InterruptedException { 
        // save thumbnail image to OUTFILE 
        //System.out.println("infile:" + infile); 
        BufferedImage thumbImage = null; 
        BufferedOutputStream out = null; 
        Image image = null; 
        image = Toolkit.getDefaultToolkit().createImage(infile); 
        MediaTracker mediaTracker = new MediaTracker(new Container()); 
        mediaTracker.addImage(image, 0); 
        mediaTracker.waitForID(0); 
        int thumbWidth = width; 
        int thumbHeight = height; 
        double thumbRatio = (double) thumbWidth / (double) thumbHeight; 
        int imageWidth = image.getWidth(null); 
        int imageHeight = image.getHeight(null); 
        double imageRatio = (double) imageWidth / (double) imageHeight; 
        if (thumbRatio < imageRatio) { 
            thumbHeight = (int) (thumbWidth / imageRatio); 
        } else { 
            thumbWidth = (int) (thumbHeight * imageRatio); 
        } 
        thumbImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_RGB); 
        Graphics2D graphics2D = thumbImage.createGraphics(); 
        graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); 
        graphics2D.drawImage(image,0,0, thumbWidth, thumbHeight, null); 
        out = new BufferedOutputStream(new FileOutputStream(outfile)); 
        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); 
        JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(thumbImage); 
        quality = Math.max(0, Math.min(quality, 100)); 
        param.setQuality((float) quality / 100.0f, false); 
        encoder.setJPEGEncodeParam(param); 
        encoder.encode(thumbImage); 
        out.close(); 
        thumbImage = null; 
        out = null; 
        image = null; 
    } 
}