java图片生成缩略图

1、方法1：第一种方法比后一种生成的缩略图要清晰Java代码1.importjavax.imageio.ImageIO;2.importjava.awt.image.BufferedImage;3.importjava.awt.image.ColorModel;4.importjava.awt.image.WritableRaster;5.importjava.awt.*;6.importjava.awt.geom.AffineTransform;7.importjava.io.InputStream;8.importjava.io.File;9.importjava.io.FileOutputS

2、tream;10.11.publicclassTest12.publicstaticBufferedImageresize(BufferedImagesource,inttargetW,inttargetH)13./targetW，targetH分别表示目标长和宽inttype=source.getType();BufferedImagetarget=null;doublesx=(double)targetW/source.getWidth();doublesy=(double)targetH/source.getHeight();18./这里想实现在targetW，targetH范围内实现等

3、比缩放。如果不需要等比缩放19./则将下面的ifelse语句注释即可if(sxsy)sx=sy;targetW=(int)(sx*source.getWidth();elsesy=sx;targetH=(int)(sy*source.getHeight();if(type=BufferedImage.TYPE_CUSTOM)/handmadeColorModelcm=source.getColorModel();WritableRasterraster=cm.createCompatibleWritableRaster(targetW,targetH);booleanalphaPremulti

4、plied=cm.isAlphaPremultiplied();target=newBufferedImage(cm,raster,alphaPremultiplied,null);elsetarget=newBufferedImage(targetW,targetH,type);Graphics2Dg=target.createGraphics();/smootherthanexlax:g.setRenderingHint(RenderingHints.KEY_RENDERING,RenderingHints.VALUE_RENDER_QUALITY);g.drawRenderedImage

5、(source,AffineTransform.getScaleInstance(sx,sy);g.dispose();returntarget;publicstaticvoidsaveImageAsJpg(StringfromFileStr,StringsaveToFileStr,intwidth,inthight)throwsExceptionBufferedImagesrcImage;/Stringex=fromFileStr.substring(fromFileStr.indexOf(.),fromFileStr.length();StringimgType=JPEG;if(fromF

6、ileStr.toLowerCase().endsWith(.png)imgType=PNG;/System.out.println(ex);FilesaveFile=newFile(saveToFileStr);FilefromFile=newFile(fromFileStr);srcImage=ImageIO.read(fromFile);if(width0|hight0)srcImage=resize(srcImage,width,hight);ImageIO.write(srcImage,imgType,saveFile);59.60.61.publicstaticvoidmain(S

7、tringargv)try参数1(from),参数2(to),参数3(宽)，参数4(高)Test.saveImageAsJpg(E:/Document/MyPictures/3.gif,c:/6.gif,50,50);catch(Exceptione)e.printStackTrace();70.importjavax.imageio.ImageIO;importjava.awt.image.BufferedImage;importjava.awt.image.ColorModel;importjava.awt.image.WritableRaster;importjava.awt.*;imp

8、ortjava.awt.geom.AffineTransform;importjava.io.InputStream;importjava.io.File;importjava.io.FileOutputStream;publicclassTestpublicstaticBufferedImageresize(BufferedImagesource,inttargetW,inttargetH)/targetW，targetH分别表示目标长和宽inttype=source.getType();BufferedImagetarget=null;doublesx=(double)targetW/so

9、urce.getWidth();doublesy=(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ifelse语句注释即可if(sxsy)sx=sy;targetW=(int)(sx*source.getWidth();elsesy=sx;targetH=(int)(sy*source.getHeight();if(type=BufferedImage.TYPE_CUSTOM)/handmadeColorModelcm=source.getColorModel();Writabl

10、eRasterraster=cm.createCompatibleWritableRaster(targetW,targetH);booleanalphaPremultiplied=cm.isAlphaPremultiplied();target=newBufferedImage(cm,raster,alphaPremultiplied,null);elsetarget=newBufferedImage(targetW,targetH,type);Graphics2Dg=target.createGraphics();/smootherthanexlax:g.setRenderingHint(

11、RenderingHints.KEY_RENDERING,RenderingHints.VALUE_RENDER_QUALITY);g.drawRenderedImage(source,AffineTransform.getScaleInstance(sx,sy);g.dispose();returntarget;publicstaticvoidsaveImageAsJpg(StringfromFileStr,StringsaveToFileStr,intwidth,inthight)throwsExceptionBufferedImagesrcImage;/Stringex=fromFile

12、Str.substring(fromFileStr.indexOf(.),fromFileStr.length();StringimgType=JPEG;if(fromFileStr.toLowerCase().endsWith(.png)imgType=PNG;/System.out.println(ex);FilesaveFile=newFile(saveToFileStr);FilefromFile=newFile(fromFileStr);srcImage=ImageIO.read(fromFile);if(width0|hight0)srcImage=resize(srcImage,

13、width,hight);ImageIO.write(srcImage,imgType,saveFile);publicstaticvoidmain(Stringargv)try参数1(from),参数2(to),参数3(宽)，参数4(高)Test.saveImageAsJpg(E:/Document/MyPictures/3.gif,c:/6.gif,50,50);catch(Exceptione)e.printStackTrace();方法2：Java代码importjava.io.*;importjava.util.*;importcom.sun.image.codec.jpeg.*;i

14、mportjava.awt.image.*;importjava.awt.*;.*;importjava.applet.*;importjava.sql.*;9.10./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)publicclassTesStringInputDir;/输入图路径StringOutputDir;/输出图路径StringInputFileName;/输入图文件名StringOutputFileName;

15、/输出图文件名intOutputWidth=80;/默认输出图片宽intOutputHeight=80;/默认输出图片高intrate=0;booleanproportion=true;/是否等比缩放标记(默认为等比缩放)23.publicTes()/初始化变量InputDir=;OutputDir=;InputFileName=;OutputFileName=;OutputWidth=80;OutputHeight=80;rate=0;34.publicvoidsetInputDir(StringInputDir)this.InputDir=InputDir;38.publicvoidset

16、OutputDir(StringOutputDir)this.OutputDir=OutputDir;42.publicvoidsetInputFileName(StringInputFileName)this.InputFileName=InputFileName;46.publicvoidsetOutputFileName(StringOutputFileName)this.OutputFileName=OutputFileName;50.publicvoidsetOutputWidth(intOutputWidth)this.OutputWidth=OutputWidth;54.publ

17、icvoidsetOutputHeight(intOutputHeight)this.OutputHeight=OutputHeight;58.publicvoidsetW_H(intwidth,intheight)this.OutputWidth=width;this.OutputHeight=height;63.publicStrings_pic()BufferedImageimage;StringNewFileName;67./建立输出文件对象68.Filefile=newFile(OutputDir+OutputFileName);69.FileOutputStreamtempout=

18、null;trytempout=newFileOutputStream(file);catch(Exceptionex)System.out.println(ex.toString();Imageimg=null;Toolkittk=Toolkit.getDefaultToolkit();Appletapp=newApplet();MediaTrackermt=newMediaTracker(app);tryimg=tk.getImage(InputDir+InputFileName);mt.addImage(img,0);mt.waitForID(0);catch(Exceptione)e.

19、printStackTrace();86.if(img.getWidth(null)=-1)System.out.println(cantread,retry!+);returnno;elseintnew_w;intnew_h;if(portion=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doublerate1=(double)img.getWidth(null)/(double)OutputWidth+0.1;doublerate2=(double)img.getHeight(null)/(double)OutputHeight+0.1;doubl

20、erate=rate1rate2?rate1:rate2;new_w=(int)(double)img.getWidth(null)/rate);new_h=(int)(double)img.getHeight(null)/rate);elsenew_w=OutputWidth;/输出的图片宽度new_h=OutputHeight;/输出的图片高度BufferedImagebuffImg=newBufferedImage(new_w,new_h,BufferedImage.TYPE_INT_RGB);108.109.Graphicsg=buffImg.createGraphics();110.

21、111.g.setColor(Color.white);112.g.fillRect(0,0,new_w,new_h);113.114.g.drawImage(img,0,0,new_w,new_h,null);115.g.dispose();116.JPEGImageEncoderencoder=JPEGCodec.createJPEGEncoder(tempout);tryencoder.encode(buffImg);tempout.close();catch(IOExceptionex)System.out.println(ex.toString();returnok;127.publicStrings_pic(StringInputDir,StringOutputDir,StringInputFileName,StringOutputFileName)/输入