17.thumbHeight=（int）（thumbWidth/imageRatio）;
18.}else{
19.thumbWidth=（int）（thumbHeight*imageRatio）;
20.}
21.
22.//draworiginalimagetothumbnailimageobjectand
23.//scaleittothenewsizeon-the-fly
24.BufferedImagethumbImage=newBufferedImage（thumbWidth,thumbHeight,BufferedImage.TYPE_INT_RGB）;
25.Graphics2Dgraphics2D=thumbImage.createGraphics（）;
26.graphics2D.setRenderingHint（RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BILINEAR）;
27.graphics2D.drawImage（image,0,0,thumbWidth,thumbHeight,null）;
28.
29.//savethumbnailimagetooutFilename
30.BufferedOutputStreamout=newBufferedOutputStream（newFileOutputStream（outFilename））;
31.JPEGImageEncoderencoder=JPEGCodec.createJPEGEncoder（out）;
32.JPEGEncodeParamparam=encoder.getDefaultJPEGEncodeParam（thumbImage）;
33.quality=Math.max（0,Math.min（quality,100））;
34.param.setQuality（（float）quality/100.0f,false）;
35.encoder.setJPEGEncodeParam（param）;
36.encoder.encode（thumbImage）;
37.out.close（）;
38.}
9.创建JSON格式的数据
请先阅读这篇文章了解一些细节，
并下面这个JAR文件：
json-rpc-1.0.jar（75kb）
1.importorg.json.JSONObject;
2....
3....
4.JSONObjectjson=newJSONObject（）;
5.json.put（"city","Mumbai"）;
6.json.put（"country","India"）;
7....
8.Stringoutput=json.toString（）;
9....
10.使用iTextJAR生成PDF
阅读这篇文章了解更多细节
1.importjava.io.File;
2.importjava.io.FileOutputStream;
3.importjava.io.OutputStream;
4.importjava.util.Date;
5.
6.importcom.lowagie.text.Document;
7.importcom.lowagie.text.Paragraph;
8.importcom.lowagie.text.pdf.PdfWriter;
9.
10.publicclassGeneratePDF{
11.
12.publicstaticvoidmain（String[]args）{
13.try{
14.OutputStreamfile=newFileOutputStream（newFile（"C:
\\Test.pdf"））;
15.
16.Documentdocument=newDocument（）;
17.PdfWriter.getInstance（document,file）;
18.document.open（）;
19.document.add（newParagraph（"HelloKiran"））;
20.document.add（newParagraph（newDate（）.toString（）））;
21.
22.document.close（）;
23.file.close（）;
24.
25.}catch（Exceptione）{
26.
27.e.printStackTrace（）;
28.}
29.}
30.}
11.HTTP代理设置
阅读这篇文章了解更多细节。
1.System.getProperties（）.put（"http.proxyHost","someProxyURL"）;
2.System.getProperties（）.put（"http.proxyPort","someProxyPort"）;
3.System.getProperties（）.put（"http.proxyUser","someUserName"）;
4.System.getProperties（）.put（"http.proxyPassword","somePassword"）;
2.单实例Singleton示例
请先阅读这篇文章了解更多信息
1.publicclassSimpleSingleton{
2.privatestaticSimpleSingletonsingleInstance=newSimpleSingleton（）;
3.
4.//Markingdefaultconstructorprivate
5.//toavoiddirectinstantiation.
6.privateSimpleSingleton（）{
7.}
8.
9.//GetinstanceforclassSimpleSingleton
10.publicstaticSimpleSingletongetInstance（）{
11.
12.returnsingleInstance;
13.}
14.}
另一种实现
1.publicenumSimpleSingleton{
2.INSTANCE;
3.publicvoiddoSomething（）{
4.}
5.}
6.
7.//CallthemethodfromSingleton:
8.SimpleSingleton.INSTANCE.doSomething（）;
13.抓屏程序
阅读这篇文章获得更多信息。
1.importjava.awt.Dimension;
2.importjava.awt.Rectangle;
3.importjava.awt.Robot;
4.importjava.awt.Toolkit;
5.importjava.awt.image.BufferedImage;
6.importjavax.imageio.ImageIO;
7.importjava.io.File;
8.
9....
10.
11.publicvoidcaptureScreen（StringfileName）throwsException{
12.
13.DimensionscreenSize=Toolkit.getDefaultToolkit（）.getScreenSize（）;
14.RectanglescreenRectangle=newRectangle（screenSize）;
15.Robotrobot=newRobot（）;
16.BufferedImageimage=robot.createScreenCapture（screenRectangle）;
17.ImageIO.write（image,"png",newFile（fileName））;
18.
19.}
20....
14.列出文件和目录
1.Filedir=newFile（"directoryName"）;
2.String[]children=dir.list（）;
3.if（children==null）{
4.//Eitherdirdoesnotexistorisnotadirectory
5.}else{
6.for（inti=0;i7.//Getfilenameoffileordirectory
8.Stringfilename=children[i];
9.}
10.}
11.
12.//Itisalsopossibletofilterthelistofreturnedfiles.
13.//Thisexampledoesnotreturnanyfilesthatstartwith`.'.
14.FilenameFilterfilter=newFilenameFilter（）{
15.publicbooleanaccept（Filedir,Stringname）{
16.return!
name.startsWith（"."）;
17.}
18.};
19.children=dir.list（filter）;
20.
21.//ThelistoffilescanalsoberetrievedasFileobjects
22.File[]files=dir.listFiles（）;
23.
24.//Thisfilteronlyreturnsdirectories
25.FileFilterfileFilter=newFileFilter（）{
26.publicbooleanaccept（Filefile）{
27.returnfile.isDirectory（）;
28.}
29.};
30.files=dir.listFiles（fileFilter）;
15.创建ZIP和JAR文件
1.importjava.util.zip.*;
2.importjava.io.*;
3.
4.publicclassZipIt{
5.publicstaticvoidmain（Stringargs[]）throwsIOException{
6.if（args.length<2）{
7.System.err.println（"usage:
javaZipItZip.zipfile1file2file3"）;
8.System.exit（-1）;
9.}
10.FilezipFile=newFile（args[0]）;
11.if（zipFile.exists（））{
12.System.err.println（"Zipfilealreadyexists,pleasetryanother"）;
13.System.exit（-2）;
14.}
15.FileOutputStreamfos=newFileOutputStream（zipFile）;
16.ZipOutputStreamzos=newZipOutputStream（fos）;
17.intbytesRead;
18.byte[]buffer=newbyte[1024];
19.CRC32crc=newCRC32（）;
20.for（inti=1,n=args.length;i21.Stringname=args[i];
22.Filefile=newFile（name）;
23.if（!
file.exists（））{
24.System.err.println（"Skipping:
"+name）;
25.continue;
26.}
27.BufferedInputStreambis=newBufferedInputStream（
28.newFileInputStream（file））;
29.crc.reset（）;
30.while（（bytesRead=bis.read（buffer））!
=-1）{
31.crc.update（buffer,0,bytesRead）;
32.}
33.bis.close（）;
34.//Resettobeginningofinputstream
35.bis=newBufferedInputStream（
36.new
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