Java生成缩略图

来源：互联网发布：java md5密钥加密算法编辑：程序博客网时间：2024/06/18 13:08
代码如下，但存在缩略图质量与原图差不多时大小会反而变大的问题：
import java.awt.Container;import java.awt.Graphics2D;import java.awt.Image;//MediaTracker：用于跟踪图像对象状态的工具类import java.awt.MediaTracker;//RenderingHints:定义和管理键和关联值的集合以允许应用程序将输入提供给呈现图像的类算法选择import java.awt.RenderingHints;//Toolkit 的子类被用于将各种组件绑定到特定本机工具包实现import java.awt.Toolkit;import java.awt.image.BufferedImage;import java.io.BufferedOutputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGEncodeParam;import com.sun.image.codec.jpeg.JPEGImageEncoder;public class MiniPic {//创建缩略图private static void createThumbnail(String filename, int thumbWidth, int thumbHeight, int quality, String outFilename)          throws InterruptedException, FileNotFoundException, IOException      {          // 根据filename加载图片        Image image = Toolkit.getDefaultToolkit().getImage(filename);          MediaTracker mediaTracker = new MediaTracker(new Container());          mediaTracker.addImage(image, 0);        //MediaTracker.waitForID(int id)：等待id图片加载完成，id用于标识图片         mediaTracker.waitForID(0);          // 测试图片的错误状态: System.out.println(mediaTracker.isErrorAny());           //决定缩略图的宽高        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);          }           BufferedImage 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);           //保存缩略图到指定路径下（outfilename)        BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(outFilename));          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);        System.out.println("缩略图程序运行正常");        out.close();              } public static void main(String args[])    {try {createThumbnail("C:\\Users\\ws\\Desktop\\jj.jpg", 600, 400, 30, "C:\\Users\\ws\\Desktop\\wws.jpg");} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}    }}
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