Java生成缩略图工具类

更新日期20150902

package com.jh.util;

import java.awt.Container;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.io.BufferedOutputStream;
import java.io.File;
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;

/**
 * @desc生成图片缩略图
 **/
@SuppressWarnings("restriction")
public class ImageThumbnailUtil {
	public static void main(String[] args) {
		String filename = "src/love.jpg";
		String outFilename = "src/love_thumb.jpg";
		try {
			createThumbnail(filename, 390, 225, 100, outFilename);
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	public static void toThumbnail(String uploadPath,String fileName){
		String uploadThumbPath =uploadPath+"/thumb/";
		File file = new File(uploadThumbPath);
		if (!file.isFile()) {
			file.mkdirs();
		}
		System.out.println(uploadPath+fileName);
		System.out.println(uploadThumbPath+fileName);
		try {
			createThumbnail(uploadPath+"/"+fileName, 390, 225, 100, uploadThumbPath+fileName);
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

private static void createThumbnail(String filename, int thumbWidth,int thumbHeight, int quality, String outFilename)
		throws InterruptedException,FileNotFoundException, IOException {

		// 加载图片文件
		Image image = Toolkit.getDefaultToolkit().getImage(filename);
		MediaTracker mediaTracker = new MediaTracker(new Container());
		mediaTracker.addImage(image, 0);
		// 强制加载图像
		mediaTracker.waitForID(0);
		// 测试图片是否加载成功:
		System.out.println(mediaTracker.isErrorAny());

		// 通过参数判断缩略图大小
		double thumbRatio = (double) thumbWidth / (double) thumbHeight;
		int imageWidth = image.getWidth(null);
		int imageHeight = image.getHeight(null);
		double imageRatio = (double) imageWidth / (double) imageHeight;
		// 缩小
		if (thumbRatio < imageRatio) {
			thumbHeight = (int) (thumbWidth / imageRatio);
		} else {// 放大
			thumbWidth = (int) (thumbHeight * imageRatio);
		}

		// 创建缩略图对象 并设置quality
		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);
		// 输出缩略图
		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);
		out.close();
	}

}

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