Java处理图片三部曲

1.等比例缩小或放大图片

/**
 * Create time May 31, 2009 4:33:31 PM
 */
package com.yd.image;

import java.awt.Canvas;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.AreaAveragingScaleFilter;
import java.awt.image.BufferedImage;
import java.awt.image.FilteredImageSource;
import java.io.File;

import javax.imageio.ImageIO;

/**
 * <p>Title: ZoomImage</p>
 * <p>Description: </p>
 *
 * @author Yaodi
 * @version 1.0
 */
public class ZoomImage {

	private static Component component = new Canvas();

	private static String[] imageFormatArray = new String[] { ".jpg", ".jpeg", ".gif", ".png", ".bmp" };//pcx/tga/tif这三种格式目前还不支持

	/**  
	 * 校验图像文件的格式是否可以进行缩放  
	 */
	public boolean verifyImageFormat(String fileName) {
		boolean result = false;
		for (int i = 0; i < imageFormatArray.length; i++) {
			if (fileName.toLowerCase().lastIndexOf(imageFormatArray[i]) == (fileName
					.length() - imageFormatArray[i].length())) {
				result = true;
				break;
			}
		}
		return result;
	}

	
	/**  
	 * 将目录下的所有图像进行放大缩小  
	 *   
	 * @param strDir 图像的目录  
	 * @param zoomRatio 放大缩小的倍率  
	 * @param rebuild 是否重新创建，即已经存在的图像是否覆盖重建  
	 * @throws Exception  
	 */
	public void zoom(String strDir, double zoomRatio, boolean rebuild)
			throws Exception {
		File fileDir = new File(strDir);
		if (!fileDir.exists()) {
			return;
		}
		String dirTarget = strDir + "/small" + zoomRatio;
		File fileTarget = new File(dirTarget);
		if (!fileTarget.exists()) {
			fileTarget.mkdir();
		}
		File[] files = fileDir.listFiles();
		StringBuilder stringBuilder = new StringBuilder();
		for (int i = 0; i < files.length; i++) {
			String fileFullName = files[i].getCanonicalPath();
			String fileShortName = files[i].getName();
			if (!new File(fileFullName).isDirectory())// 排除二级目录，如果想就再递归一次，这里省略   
			{
				if (verifyImageFormat(fileShortName)) {

					stringBuilder = new StringBuilder();
					stringBuilder.append(dirTarget).append("/").append(
							fileShortName);
					if (!new File(stringBuilder.toString()).exists() || rebuild) {
						try {
							createZoomSizeImage(fileFullName, stringBuilder
									.toString(), zoomRatio);
						} catch (Exception e) {

						}
					}
				}
			}
		}
	}

	
	/**  
	 * 按比例进行放大或缩小图像，zoomRatio = 1为原大，zoomRatio > 1为放大，zoomRatio < 1 为缩小  
	 */
	public void createZoomSizeImage(String fileName, String fileNameTarget,
			double zoomRatio) throws Exception {
		Image image = ImageIO.read(new File(fileName));
		int width = new Double(image.getWidth(null) * zoomRatio).intValue();
		int height = new Double(image.getHeight(null) * zoomRatio).intValue();
		AreaAveragingScaleFilter areaAveragingScaleFilter = new AreaAveragingScaleFilter(
				width, height);
		FilteredImageSource filteredImageSource = new FilteredImageSource(image
				.getSource(), areaAveragingScaleFilter);
		BufferedImage bufferedImage = new BufferedImage(width, height,
				BufferedImage.TYPE_3BYTE_BGR);
		Graphics graphics = bufferedImage.createGraphics();
		graphics.drawImage(component.createImage(filteredImageSource), 0, 0,
				null);
		ImageIO.write(bufferedImage, "JPEG", new File(fileNameTarget));
	}

	
	public static void main(String[] args) throws Exception {
		ZoomImage zoomImage = new ZoomImage();		
		zoomImage.zoom("F:/pic", 0.25, false);// 缩小2倍   		
		//zoomImage.zoom("F:/pic",2,true);// 放大2倍   
		System.out.println("************THEEND************");
	}
}

2.按坐标裁切图片

/**
 * Create time May 31, 2009 4:33:31 PM
 */
package com.yd.image;

import java.awt.Rectangle;
import java.awt.image.BufferedImage;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Iterator;

import javax.imageio.ImageIO;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;


/**
 * <p>Title: CutImage</p>
 * <p>Description: </p>
 *
 * @author Yaodi
 * @version 1.0
 */
public class CutImage {
	
	private static int x_share = 8; //x切片份数
	private static int y_share = 10; //y切片份数
	private static String srcpath = "F:/pic/xiaohei.jpg"; //源图片路径名称
	private static String subpath = "F:/pic/cut/"; //剪切图片存放的目录	
	private int x; //剪切点x坐标
	private int y; //剪切点y坐标	
	private int width; //剪切点宽度
	private int height; //剪切点高度
	private int num;

	public CutImage() { }

	public CutImage(int x, int y, int width, int height, int num) {
		this.x = x;
		this.y = y;
		this.width = width;
		this.height = height;
		this.num = num;
	}

	/**
	 * 对图片裁剪，并把裁剪完的新图片保存
	 */
	public void cut() throws IOException {

		FileInputStream is = null;
		ImageInputStream iis = null;

		try {
			// 读取图片文件
			is = new FileInputStream(srcpath);

			/**
			 * 返回包含所有当前已注册 ImageReader 的 Iterator，这些 ImageReader 声称能够解码指定格式。
			 * 参数：formatName - 包含非正式格式名称 . （例如 "jpeg" 或 "tiff"）等 。
			 */
			Iterator<ImageReader> it = ImageIO
					.getImageReadersByFormatName("jpg");
			ImageReader reader = it.next();
			// 获取图片流
			iis = ImageIO.createImageInputStream(is);

			/**
			 * iis:读取源.true:只向前搜索.将它标记为 ‘只向前搜索’。 此设置意味着包含在输入源中的图像将只按顺序读取，可能允许
			 * reader 避免缓存包含与以前已经读取的图像关联的数据的那些输入部分。
			 */
			reader.setInput(iis, true);

			/**
			 * <p>
			 * 描述如何对流进行解码的类
			 * <p>
			 * .用于指定如何在输入时从 Java Image I/O 框架的上下文中的流转换一幅图像或一组图像。用于特定图像格式的插件 将从其
			 * ImageReader 实现的 getDefaultReadParam 方法中返回 ImageReadParam 的实例。
			 */
			ImageReadParam param = reader.getDefaultReadParam();

			/**
			 * 图片裁剪区域。Rectangle 指定了坐标空间中的一个区域，通过 Rectangle 对象
			 * 的左上顶点的坐标（x，y）、宽度和高度可以定义这个区域。
			 */
			Rectangle rect = new Rectangle(x, y, width, height);

			// 提供一个 BufferedImage，将其用作解码像素数据的目标。
			param.setSourceRegion(rect);

			/**
			 * 使用所提供的 ImageReadParam 读取通过索引 imageIndex 指定的对象，并将 它作为一个完整的
			 * BufferedImage 返回。
			 */
			BufferedImage bi = reader.read(0, param);

			// 保存新图片
			ImageIO.write(bi, "jpg", new File(subpath + num + ".jpg"));
		} finally {
			if (is != null)
				is.close();
			if (iis != null)
				iis.close();
		}
	}

	public static void main(String[] args) throws IOException {
		BufferedImage bufferedImage = ImageIO.read(new File(srcpath));		
		File file = new File(subpath); //创建切片存放的目录
		file.mkdirs();
		
		int init_width = bufferedImage.getWidth(); //获得原始图片的宽
		int init_height = bufferedImage.getHeight(); //获得原始图片的高		
		int x = 0; //x坐标点
		int y = 0; //y坐标点
		int width = init_width / x_share; //裁切后图片的宽
		int height = init_height / y_share; //裁切后图片的高
		int sum = (init_width / width) * (init_height / height); //获得切片的总数

		for (int i = 1; i <= sum; i++) {
			if (x == init_width) {
				x = 0;
				y = y + height; //y坐标移动
			}
			CutImage ci = new CutImage(x, y, width, height, i);
			x = x + width; //x坐标移动
			try {
				ci.cut();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}

		System.out.println("************THEEND************");
	}
}

图片宽和高必须要被切片份数整除

3.判断图片是否相同

/**
 * Create time May 31, 2009 4:33:31 PM
 */
package com.yd.image;

import java.io.File;
import java.security.MessageDigest;

/**
 * <p>Title: MD5Image</p>
 * <p>Description: </p>
 *
 * @author Yaodi
 * @version 1.0
 */
public class MD5Image {

	/**
	 * MD5加密的方式判断图片是否相同
	 */
	public static String MD5(byte[] s) {
		char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
				'a', 'b', 'c', 'd', 'e', 'f' };//16进制字符
		try {
			byte[] strTemp = s;
			MessageDigest mdTemp = MessageDigest.getInstance("MD5");
			mdTemp.update(strTemp);
			byte[] md = mdTemp.digest();
			int j = md.length;
			char str[] = new char[j * 2];
			int k = 0;//移位 输出字符串
			for (int i = 0; i < j; i++) {
				byte byte0 = md[i];
				str[k++] = hexDigits[byte0 >>> 4 & 0xf];
				str[k++] = hexDigits[byte0 & 0xf];
			}
			return new String(str);
		} catch (Exception e) {
			return null;
		}
	}


	public static void main(String[] args) {
		//44f24b510805d6c8ed2aec46817ebb5e
		File file = new File("F:/pic/xiaohei.jpg");
		byte[] b = new byte[(int) file.length()];
		System.out.println(MD5Image.MD5(b));
	}

}

通过生成的MD5码，进行判断筛选出文件夹中相同的图片