java圖片生成縮略圖

1、方法1：第一種方法比后一種生成的縮略圖要清晰Java代碼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分別表示目標(biāo)長和寬inttype=source.getType();BufferedImagetarget=null;doublesx=(double)targetW/source.getWidth();doublesy=(double)targetH/source.getHeight();18./這里想實現(xiàn)在targetW，targetH范圍內(nèi)實現(xiàn)等

3、比縮放。如果不需要等比縮放19./則將下面的ifelse語句注釋即可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參數(shù)1(from),參數(shù)2(to),參數(shù)3(寬)，參數(shù)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分別表示目標(biāo)長和寬inttype=source.getType();BufferedImagetarget=null;doublesx=(double)targetW/so

9、urce.getWidth();doublesy=(double)targetH/source.getHeight();/這里想實現(xiàn)在targetW，targetH范圍內(nèi)實現(xiàn)等比縮放。如果不需要等比縮放/則將下面的ifelse語句注釋即可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參數(shù)1(from),參數(shù)2(to),參數(shù)3(寬)，參數(shù)4(高)Test.saveImageAsJpg(E:/Document/MyPictures/3.gif,c:/6.gif,50,50);catch(Exceptione)e.printStackTrace();方法2：Java代碼importjava.io.*;importjava.util.*;importcom.sun.image.codec.jpeg.*;i

14、mportjava.awt.image.*;importjava.awt.*;.*;importjava.applet.*;importjava.sql.*;9.10./縮略圖類，/本java類能將jpg圖片文件，進(jìn)行等比或非等比的大小轉(zhuǎn)換。/具體使用方法/s_pic(大圖片路徑，生成小圖片路徑,大圖片文件名，生成小圖片文名，生成小圖片寬度，生成小圖片高度，是否等比縮放(默認(rèn)為true)publicclassTesStringInputDir;/輸入圖路徑StringOutputDir;/輸出圖路徑StringInputFileName;/輸入圖文件名StringOutputFileName;

15、/輸出圖文件名intOutputWidth=80;/默認(rèn)輸出圖片寬intOutputHeight=80;/默認(rèn)輸出圖片高intrate=0;booleanproportion=true;/是否等比縮放標(biāo)記(默認(rèn)為等比縮放)23.publicTes()/初始化變量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./建立輸出文件對象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)/判斷是否是等比縮放./為等比縮放計算輸出的圖片寬度及高度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;/輸出的圖片寬度new_h=OutputHeight;/輸出的圖片高度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)/輸入