package com.yipai.util;

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

import javax.imageio.ImageIO;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ImageCompressUtil {
	/**
	 * 直接指定壓縮後的寬高：
	 * (先儲存原檔案，再壓縮、上傳)
	 * 壹拍專案中用於二維碼壓縮
	 * @param oldFile 要進行壓縮的檔案全路徑
	 * @param width 壓縮後的寬度
	 * @param height 壓縮後的高度
	 * @param quality 壓縮質量
	 * @param smallIcon 檔名的小小字尾(注意，非檔案字尾名稱),入壓縮檔名是yasuo.jpg,則壓縮後文件名是yasuo(+smallIcon).jpg
	 * @return 返回壓縮後的檔案的全路徑
	 */
	public static String zipImageFile(String oldFile, int width, int height,
			float quality, String smallIcon) {
		if (oldFile == null) {
			return null;
		}
		String newImage = null;
		try {
			/**對伺服器上的臨時檔案進行處理 */
			Image srcFile = ImageIO.read(new File(oldFile));
			/** 寬,高設定 */
			BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
			tag.getGraphics().drawImage(srcFile, 0, 0, width, height, null);
			String filePrex = oldFile.substring(0, oldFile.indexOf('.'));
			/** 壓縮後的檔名 */
			newImage = filePrex + smallIcon	+ oldFile.substring(filePrex.length());
			/** 壓縮之後臨時存放位置 */
			FileOutputStream out = new FileOutputStream(newImage);
			JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
			JPEGEncodeParam jep = JPEGCodec.getDefaultJPEGEncodeParam(tag);
			/** 壓縮質量 */
			jep.setQuality(quality, true);
			encoder.encode(tag, jep);
			out.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return newImage;
	}

	/**
	 * 儲存檔案到伺服器臨時路徑(用於檔案上傳)
	 * @param fileName
	 * @param is
	 * @return 檔案全路徑
	 */
	public static String writeFile(String fileName, InputStream is) {
		if (fileName == null || fileName.trim().length() == 0) {
			return null;
		}
		try {
			/** 首先儲存到臨時檔案 */
			FileOutputStream fos = new FileOutputStream(fileName);
			byte[] readBytes = new byte[512];// 緩衝大小
			int readed = 0;
			while ((readed = is.read(readBytes)) > 0) {
				fos.write(readBytes, 0, readed);
			}
			fos.close();
			is.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return fileName;
	}

	/**
	 * 等比例壓縮演算法： 
	 * 演算法思想：根據壓縮基數和壓縮比來壓縮原圖，生產一張圖片效果最接近原圖的縮圖
	 * @param srcURL 原圖地址
	 * @param deskURL 縮圖地址
	 * @param comBase 壓縮基數
	 * @param scale 壓縮限制(寬/高)比例  一般用1：
	 * 當scale>=1,縮圖height=comBase,width按原圖寬高比例;若scale<1,縮圖width=comBase,height按原圖寬高比例
	 * @throws Exception
	 * @author shenbin
	 * @createTime 2014-12-16
	 * @lastModifyTime 2014-12-16
	 */
	public static void saveMinPhoto(String srcURL, String deskURL, double comBase,
			double scale) throws Exception {
		File srcFile = new java.io.File(srcURL);
		Image src = ImageIO.read(srcFile);
		int srcHeight = src.getHeight(null);
		int srcWidth = src.getWidth(null);
		int deskHeight = 0;// 縮圖高
		int deskWidth = 0;// 縮圖寬
		double srcScale = (double) srcHeight / srcWidth;
		/**縮圖寬高演算法*/
		if ((double) srcHeight > comBase || (double) srcWidth > comBase) {
			if (srcScale >= scale || 1 / srcScale > scale) {
				if (srcScale >= scale) {
					deskHeight = (int) comBase;
					deskWidth = srcWidth * deskHeight / srcHeight;
				} else {
					deskWidth = (int) comBase;
					deskHeight = srcHeight * deskWidth / srcWidth;
				}
			} else {
				if ((double) srcHeight > comBase) {
					deskHeight = (int) comBase;
					deskWidth = srcWidth * deskHeight / srcHeight;
				} else {
					deskWidth = (int) comBase;
					deskHeight = srcHeight * deskWidth / srcWidth;
				}
			}
		} else {
			deskHeight = srcHeight;
			deskWidth = srcWidth;
		}
		BufferedImage tag = new BufferedImage(deskWidth, deskHeight, BufferedImage.TYPE_3BYTE_BGR);
		tag.getGraphics().drawImage(src, 0, 0, deskWidth, deskHeight, null); //繪製縮小後的圖
		FileOutputStream deskImage = new FileOutputStream(deskURL); //輸出到檔案流
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(deskImage);
		encoder.encode(tag); //近JPEG編碼
		deskImage.close();
	}

	public static void main(String args[]) throws Exception {
		ImageCompressUtil.zipImageFile("f:/食屍鬼 - 藿香.jpg", 1280, 1280, 1f, "x2");
		ImageCompressUtil.saveMinPhoto("f:/食屍鬼 - 藿香.jpg", "f:/11.jpg", 139, 0.9d);
	}
}

	    			
 

轉自：http://www.zuidaima.com/code/file/2156534163489792.htm?dir=/2156534163489792.java