java图片压缩技术-不错

import java.awt.Image;import java.awt.image.BufferedImage;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import javax.imageio.ImageIO;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder;public class CompressPic {/******************************************************************************* * 缩略图类（通用） 本java类能将jpg、bmp、png、gif图片文件，进行等比或非等比的大小转换。 具体使用方法 * compressPic(大图片路径,生成小图片路径,大图片文件名,生成小图片文名,生成小图片宽度,生成小图片高度,是否等比缩放(默认为true)) */private File file = null; // 文件对象private String inputDir; // 输入图路径private String outputDir; // 输出图路径private String inputFileName; // 输入图文件名private String outputFileName; // 输出图文件名private int outputWidth = 100; // 默认输出图片宽private int outputHeight = 100; // 默认输出图片高private boolean proportion = true; // 是否等比缩放标记(默认为等比缩放)public CompressPic() { // 初始化变量inputDir = "";outputDir = "";inputFileName = "";outputFileName = "";outputWidth = 100;outputHeight = 100;}public void setInputDir(String inputDir) {this.inputDir = inputDir;}public void setOutputDir(String outputDir) {this.outputDir = outputDir;}public void setInputFileName(String inputFileName) {this.inputFileName = inputFileName;}public void setOutputFileName(String outputFileName) {this.outputFileName = outputFileName;}public void setOutputWidth(int outputWidth) {this.outputWidth = outputWidth;}public void setOutputHeight(int outputHeight) {this.outputHeight = outputHeight;}public void setWidthAndHeight(int width, int height) {this.outputWidth = width;this.outputHeight = height;}/* * 获得图片大小 传入参数 String path ：图片路径 */public long getPicSize(String path) {file = new File(path);return file.length();}// 图片处理public String compressPic() {try {// 获得源文件file = new File(inputDir);//System.out.println(inputDir + inputFileName);if (!file.exists()) {//throw new Exception("文件不存在");}Image img = ImageIO.read(file);// 判断图片格式是否正确if (img.getWidth(null) == -1) {System.out.println(" can't read,retry!" + "<BR>");return "no";} else {int newWidth;int newHeight;// 判断是否是等比缩放if (this.proportion == true) {// 为等比缩放计算输出的图片宽度及高度double rate1 = ((double) img.getWidth(null))/ (double) outputWidth + 0.1;double rate2 = ((double) img.getHeight(null))/ (double) outputHeight + 0.1;// 根据缩放比率大的进行缩放控制double rate = rate1 > rate2 ? rate1 : rate2;newWidth = (int) (((double) img.getWidth(null)) / rate);newHeight = (int) (((double) img.getHeight(null)) / rate);} else {newWidth = outputWidth; // 输出的图片宽度newHeight = outputHeight; // 输出的图片高度}BufferedImage tag = new BufferedImage((int) newWidth,(int) newHeight, BufferedImage.TYPE_INT_RGB);/* * Image.SCALE_SMOOTH 的缩略算法 生成缩略图片的平滑度的 优先级比速度高 生成的图片质量比较好 但速度慢 */tag.getGraphics().drawImage(img.getScaledInstance(newWidth, newHeight,Image.SCALE_SMOOTH), 0, 0, null);File f=new File(outputDir);if (!f.exists()){f.mkdirs(); }FileOutputStream out = new FileOutputStream(outputDir+ outputFileName);// JPEGImageEncoder可适用于其他图片类型的转换JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);encoder.encode(tag);out.close();}} catch (IOException ex) {ex.printStackTrace();}return "ok";}public String compressPic(String outputDir, String inputFileName,String outputFileName) {// 输出图路径this.outputDir = outputDir;// 输入图文件名this.inputFileName = inputFileName;// 输出图文件名this.outputFileName = outputFileName;return compressPic();}public String compressPic(String inputDir, String outputDir,String inputFileName, String outputFileName, int width, int height,boolean gp) {// 输入图路径this.inputDir = inputDir;// 输出图路径this.outputDir = outputDir;// 输入图文件名this.inputFileName = inputFileName;// 输出图文件名this.outputFileName = outputFileName;// 设置图片长宽setWidthAndHeight(width, height);// 是否是等比缩放 标记this.proportion = gp;return compressPic();}}