java生成缩略图类源码

把做工程过程比较好的一些内容备份一下，如下内容段是关于 java生成缩略图类的内容。

package com.whatycms.common.util;

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

import javax.imageio.ImageIO;

import org.apache.commons.io.FileUtils;

public class ImageScale { public static void resizeFix(File srcFile, File destFile, int width, int height) throws IOException { new ImageScale(srcFile, destFile, width, height); }

public static void resizeFix(BufferedImage bufImg, File destFile, int width, int height) throws IOException {
	new ImageScale(bufImg, destFile, width, height);
}

private int width;
private int height;
private int zoomWidth;
private int zoomHeight;
private File destFile;
private BufferedImage srcBufferImage;

protected ImageScale(File srcFile, File destFile, int zoomWidth, int zoomHeight) throws IOException {
	this.destFile = destFile;
	this.zoomWidth = zoomWidth;
	this.zoomHeight = zoomHeight;
	this.srcBufferImage = javax.imageio.ImageIO.read(srcFile);
	this.width = this.srcBufferImage.getWidth();
	this.height = this.srcBufferImage.getHeight();
	if (width <= zoomWidth && height <= zoomHeight) {
		FileUtils.copyFile(srcFile, destFile);
	} else {
		resizeFix();
	}
}

protected ImageScale(BufferedImage srcBufferImage, File destFile, int zoomWidth, int zoomHeight) throws IOException {
	this.destFile = destFile;
	this.zoomWidth = zoomWidth;
	this.zoomHeight = zoomHeight;
	this.srcBufferImage = srcBufferImage;
	this.width = this.srcBufferImage.getWidth();
	this.height = this.srcBufferImage.getHeight();
	resizeFix();
}

protected void resizeFix() throws IOException {
	if (width <= zoomWidth && height <= zoomHeight) {
		resize(width, height);
	} else if ((float) width / height > (float) zoomWidth / zoomHeight) {
	} else {
	}
}

private void resize(int w, int h) throws IOException {
	BufferedImage imgBuf = scaleImage(w, h);
	File parent = destFile.getParentFile();
	if (!parent.exists()) {
		parent.mkdirs();
	}
	ImageIO.write(imgBuf, "jpeg", destFile);
}

private BufferedImage scaleImage(int outWidth, int outHeight) {
	int[] rgbArray = srcBufferImage.getRGB(0, 0, width, height, null, 0, width);
	BufferedImage pbFinalOut = new BufferedImage(outWidth, outHeight, BufferedImage.TYPE_INT_RGB);

	int winX0, winY0, winX1, winY1;
	int valueRGB = 0;
	long R, G, B;
	int x, y, i, j;
	int n;
	for (y = 0; y < outHeight; y++) {
		if (winY0 < 0) {
			winY0 = 0;
		}
		winY1 = (int) (winY0 + vScale + 0.5);
		if (winY1 > height) {
			winY1 = height;
		}
		for (x = 0; x < outWidth; x++) {
			if (winX0 < 0) {
				winX0 = 0;
			}
			winX1 = (int) (winX0 + hScale + 0.5);
			if (winX1 > width) {
				winX1 = width;
			}
			R = 0;
			G = 0;
			B = 0;
			for (i = winX0; i < winX1; i++) {
				for (j = winY0; j < winY1; j++) {
					R += getRedValue(valueRGB);
					G += getGreenValue(valueRGB);
					B += getBlueValue(valueRGB);
				}
			}
			R = (int) (((double) R) / n + 0.5);
			G = (int) (((double) G) / n + 0.5);
			B = (int) (((double) B) / n + 0.5);
			valueRGB = comRGB(clip((int) R), clip((int) G), clip((int) B));
			pbFinalOut.setRGB(x, y, valueRGB);
		}
	}
	return pbFinalOut;
}

private int clip(int x) {
	if (x < 0)
		return 0;
	if (x > 255)
		return 255;
	return x;
}

private int getRedValue(int rgbValue) {
	int temp = rgbValue & 0x00ff0000;
	return temp >> 16;
}

private int getGreenValue(int rgbValue) {
	int temp = rgbValue & 0x0000ff00;
	return temp >> 8;
}

private int getBlueValue(int rgbValue) {
	return rgbValue & 0x000000ff;
}

private int comRGB(int redValue, int greenValue, int blueValue) {

	return (redValue << 16) + (greenValue << 8) + blueValue;
}

public static void main(String[] args) throws IOException {
	long start = System.currentTimeMillis();
	ImageScale.resizeFix(new File("D:/pictures/学会忘记.bmp"), new File("D:/pictures/学会忘记2.bmp"), 60, 60);
	long end = System.currentTimeMillis();
	System.out.println("success:" + (end - start));
}

}