JAVA生成缩略图

本文来源于http://wing929.iteye.com/blog/185508,方法1中在原有的基础上增加了文件生成，及目录的生成，并且增加了以文件类型的参数的方法的重载，在服务器上传过程中可以用到。

 

方法1：[第一种方法比后一种生成的缩略图要清晰]

import javax.imageio.ImageIO;import java.awt.image.BufferedImage;import java.awt.image.ColorModel;import java.awt.image.WritableRaster;import java.awt.*;import java.awt.geom.AffineTransform;import java.io.File;import java.io.IOException;public class ImageTest {public static BufferedImage resize(BufferedImage source, int targetW,int targetH) {// targetW，targetH分别表示目标长和宽int type = source.getType();BufferedImage target = null;double sx = (double) targetW / source.getWidth();double sy = (double) targetH / source.getHeight();// 这里想实现在targetW，targetH范围内实现等比缩放。如果不需要等比缩放// 则将下面的if else语句注释即可if (sx > sy) {sx = sy;targetW = (int) (sx * source.getWidth());} else {sy = sx;targetH = (int) (sy * source.getHeight());}if (type == BufferedImage.TYPE_CUSTOM) { // handmadeColorModel cm = source.getColorModel();WritableRaster raster = cm.createCompatibleWritableRaster(targetW,targetH);boolean alphaPremultiplied = cm.isAlphaPremultiplied();target = new BufferedImage(cm, raster, alphaPremultiplied, null);} elsetarget = new BufferedImage(targetW, targetH, type);Graphics2D g = target.createGraphics();// smoother than exlax:g.setRenderingHint(RenderingHints.KEY_RENDERING,RenderingHints.VALUE_RENDER_QUALITY);g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));g.dispose();return target;}/** * @param fromFileStr * @param saveToFileStr * @param width 图片宽度 * @param hight 图片长度 * @throws Exception */public static void saveImageAsJpg(String fromFileStr, String saveToFileStr,int width, int hight) throws Exception {BufferedImage srcImage;// String ex =// fromFileStr.substring(fromFileStr.indexOf("."),fromFileStr.length());String imgType = "JPEG";if (fromFileStr.toLowerCase().endsWith(".png")) {imgType = "PNG";}// System.out.println(ex);File saveFile = new File(saveToFileStr);File fromFile = new File(fromFileStr);srcImage = ImageIO.read(fromFile);if (width > 0 || hight > 0) {srcImage = resize(srcImage, width, hight);}ImageIO.write(srcImage, imgType, saveFile);}/** * 以JPG格式保存文件 * @param srcFile 原文件 * @param destFile 要保存到的文件 * @param width 图片宽度 * @param hight 图片长度 * @throws Exception */public static void saveImageAsJpg(File srcFile, File destFile,int width, int hight) throws Exception {BufferedImage srcImage;String imgType = "JPEG";if (srcFile.getName().toLowerCase().endsWith(".png")) {imgType = "PNG";}srcImage = ImageIO.read(srcFile);if (width > 0 || hight > 0) {srcImage = resize(srcImage, width, hight);}ImageIO.write(srcImage, imgType, destFile);}public static void main(String argv[]) {try {// 参数1(from),参数2(to),参数3(宽),参数4(高)//ImageTest.saveImageAsJpg("E:/Document/My Pictures/3.gif",//"c:/6.gif", 50, 50);String fileName = "蓝.png";String srcFileName = "D:/20120201/"+fileName;String destFileName = "D:/TESTIMAGE/IMAGE/"+fileName;File srcFile = new File(srcFileName);File destFile = createFile(destFileName, "/");ImageTest.saveImageAsJpg(srcFile,destFile, 350, 350);} catch (Exception e) {e.printStackTrace();}}/** * 生成文件路径以及文件 * @param path文件路径+文件名 * @param separate文件路径分隔标识，如/ * @return */public static File createFile(String path, String separate) {createDir(path ,separate);File file = new File(path);try {if (file.exists()) {file.delete();}file.createNewFile();} catch (IOException e) {e.printStackTrace();}return file;}/** * 生成文件目录 * @param path 如果传入的是目录，结尾必须以文件分隔符结尾 * @param separate */public static void createDir(String path, String separate) {String filePath = path.substring(0, path.lastIndexOf(separate));File dir = new File(filePath);if (!dir.exists()) {createDir(filePath, separate);dir.mkdir();}}}

 

 方法2：

 import java.io.*; import java.util.*; import com.sun.image.codec.jpeg.*; import java.awt.image.*; import java.awt.*; import java.net.*; import java.applet.*; import java.sql.*;//缩略图类，//本java类能将jpg图片文件，进行等比或非等比的大小转换。//具体使用方法//s_pic(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)) public class Tes { String InputDir; //输入图路径 String OutputDir; //输出图路径 String InputFileName; //输入图文件名 String OutputFileName; //输出图文件名 int OutputWidth = 80; //默认输出图片宽 int OutputHeight = 80; //默认输出图片高 int rate = 0; boolean proportion = true; //是否等比缩放标记(默认为等比缩放) public Tes() {//初始化变量 InputDir = ""; OutputDir = ""; InputFileName = ""; OutputFileName = ""; OutputWidth = 80; OutputHeight = 80; rate = 0; } 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 setW_H(int width, int height) { this.OutputWidth = width; this.OutputHeight = height; } public String s_pic() { BufferedImage image; String NewFileName;//建立输出文件对象 File file = new File(OutputDir + OutputFileName); FileOutputStream tempout = null; try { tempout = new FileOutputStream(file); } catch (Exception ex) { System.out.println(ex.toString()); } Image img = null; Toolkit tk = Toolkit.getDefaultToolkit(); Applet app = new Applet(); MediaTracker mt = new MediaTracker(app); try { img = tk.getImage(InputDir + InputFileName); mt.addImage(img, 0); mt.waitForID(0); } catch (Exception e) { e.printStackTrace(); } if (img.getWidth(null) == -1) { System.out.println(" can't read,retry!" + "<BR>"); return "no"; } else { int new_w; int new_h; if (this.proportion == true) { //判断是否是等比缩放.//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; double rate = rate1 > rate2 ? rate1 : rate2; new_w = (int) (((double) img.getWidth(null)) / rate); new_h = (int) (((double) img.getHeight(null)) / rate); } else { new_w = OutputWidth; //输出的图片宽度 new_h = OutputHeight; //输出的图片高度 } BufferedImage buffImg = new BufferedImage(new_w, new_h, BufferedImage.TYPE_INT_RGB); Graphics g = buffImg.createGraphics(); g.setColor(Color.white); g.fillRect(0, 0, new_w, new_h); g.drawImage(img, 0, 0, new_w, new_h, null); g.dispose(); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(tempout); try { encoder.encode(buffImg); tempout.close(); } catch (IOException ex) { System.out.println(ex.toString()); } } return "ok"; } public String s_pic(String InputDir, String OutputDir, String InputFileName, String OutputFileName) {//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; return s_pic(); } public String s_pic(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 setW_H(width, height);//是否是等比缩放 标记 this.proportion = gp; return s_pic(); } public static void main(String[] a) {//s_pic(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) Tes mypic = new Tes(); System.out.println( mypic.s_pic("E:\Document\My Pictures\", "E:\Document\My Pictures\", "topbg-3.gif", "3.gif", 400, 400, true) ); } }

 

原文地址

http://wing929.iteye.com/blog/185508