再发一段java操作图像的代码

/**
* http://auzll.iteye.com */
package z.tool.util;

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import javax.imageio.ImageIO;

import org.apache.commons.io.IOUtils;
import org.apache.log4j.Logger;

import z.tool.checker.HumanNeededError;
import z.tool.checker.LogicError;

/**
* 图片工具类
* @author auzll
*/
public final class ImageUtil {
private static final Logger LOG = Logger.getLogger(ImageUtil.class);

/**
* 从{@link javax.imageio.spi.ImageReaderWriterSpi}的实现类中整理出来所有支持的图片类型
*/
public static enum ImageType {
JPEG, PNG, GIF, WBMP
}

/**
* 等比例缩放图片(Jpeg)
*/
public static void resizeAsJpeg(File srcFile, File destFile, int maxNewHeight, int maxNewWidth) {
resize(srcFile, ImageType.JPEG, destFile, maxNewHeight, maxNewWidth);
}

/**
* 等比例缩放图片(Png)
*/
public static void resizeAsPng(File srcFile, File destFile, int maxNewHeight, int maxNewWidth) {
resize(srcFile, ImageType.PNG, destFile, maxNewHeight, maxNewWidth);
}

/**
* 等比例缩放图片(Gif)
*/
public static void resizeAsGif(File srcFile, File destFile, int maxNewHeight, int maxNewWidth) {
resize(srcFile, ImageType.GIF, destFile, maxNewHeight, maxNewWidth);
}

/**
* 等比例缩放图片(Wbmp)
*/
public static void resizeAsWbmp(File srcFile, File destFile, int maxNewHeight, int maxNewWidth) {
resize(srcFile, ImageType.WBMP, destFile, maxNewHeight, maxNewWidth);
}

/**
* 等比例缩放图片
*/
public static void resize(File srcFile, ImageType destType, File destFile, int maxNewHeight, int maxNewWidth) {
if (null == srcFile || !srcFile.exists()) {
if (LOG.isDebugEnabled()) {
LOG.debug("method:resize,srcFile:"
+ (null != srcFile ? srcFile.getAbsolutePath() : null)
+ ",descr:file not found");
}
throw new LogicError("缩放的源文件不存在");
}

if (null == destType) {
throw new LogicError("未指定缩放图片类型");
}

if (null == destFile) {
throw new LogicError("缩放的目标文件为空");
}

if (maxNewHeight < 1 | maxNewWidth < 1) {
throw new LogicError("缩放尺寸错误，不能小于0");
}

try {
Image srcImage = ImageIO.read(srcFile);

// 原始图片大小
int srcImageWidth = srcImage.getWidth(null);
int srcImageHeight = srcImage.getHeight(null);

// 原始宽高超过设定的最大宽高
if (srcImageWidth > maxNewWidth || srcImageHeight > maxNewHeight) {

// 计算缩放大小
if (srcImageWidth >= srcImageHeight) {
// 原始图片的宽度大于高度，需要缩小缩放后的最大高度
maxNewHeight = (int) Math.round((srcImageHeight * maxNewWidth * 1.0 / srcImageWidth));
} else {
// 否则，缩小缩放后的最大宽度
maxNewWidth = (int) Math.round((srcImageWidth * maxNewHeight * 1.0 / srcImageHeight));
}

}

BufferedImage distImage = new BufferedImage(maxNewWidth, maxNewHeight, BufferedImage.TYPE_INT_RGB);

// 绘制新图
distImage.getGraphics().drawImage(srcImage.getScaledInstance(maxNewWidth, maxNewHeight, Image.SCALE_SMOOTH), 0, 0, null);

// 输出到文件流
OutputStream os = null;
try {
os = new FileOutputStream(destFile);
ImageIO.write(distImage, destType.name(), os);
os.flush();
} finally {
IOUtils.closeQuietly(os);
}
} catch (IOException e) {
LOG.error("method:resize,srcFile:" + (null != srcFile ? srcFile.getAbsolutePath() : null)
+ ",destFile:"  + (null != destFile ? destFile.getAbsolutePath() : null)
+ ",destType:"  + destType
+ ",maxNewHeight:"  + maxNewHeight
+ ",maxNewWidth:"  + maxNewWidth
+ ",errorMsg:" + e.getMessage(), e);
throw new HumanNeededError("图片缩放失败");
}
}
}