6.将Java中的util.Date转换成sql.Date
这一片段显示如何将一个java util Date转换成sql Date用于数据库

• java.util.Date utilDate = new java.util.Date();
• java.sql.Date sqlDate = new java.sql.Date(utilDate.getTime());
• 
  

7. 使用NIO快速复制Java文件

• public static void fileCopy( File in, File out )
• throws IOException
• {
• FileChannel inChannel = new FileInputStream( in ).getChannel ();
• FileChannel outChannel = new FileOutputStream( out ).getChannel();
• try
• {
• //          inChannel.transferTo (0, inChannel.size(), outChannel);      // original
• -- apparently has trouble copying large files on Windows
• // magic number for Windows, 64Mb - 32Kb)
• int maxCount = (64 * 1024 * 1024) - (32 * 1024);
• long size = inChannel.size ();
• long position = 0;
• while ( position < size )
• {
•   position += inChannel.transferTo( position, maxCount, outChannel );
• }
• }
• finally
• {
• if ( inChannel != null )
• {
•   inChannel.close ();
• }
• if ( outChannel != null )
• {
•    outChannel.close ();
• }
• }
• }
  

8. 在Java中创建缩略图

• private void createThumbnail(String filename, int thumbWidth, int thumbHeight, int quality, String outFilename)
• throws InterruptedException, FileNotFoundException, IOException
• {
• // load image from filename
• Image image = Toolkit.getDefaultToolkit().getImage (filename);
• MediaTracker mediaTracker = new MediaTracker(new Container());
• mediaTracker.addImage(image, 0);
• mediaTracker.waitForID(0);
• // use this to test for errors at this point: System.out.println
• (mediaTracker.isErrorAny());
• // determine thumbnail size from WIDTH and HEIGHT
• double thumbRatio = (double)thumbWidth / (double) thumbHeight;
• int imageWidth = image.getWidth (null);
• int imageHeight = image.getHeight (null);
• double imageRatio = (double)imageWidth / (double) imageHeight;
• if (thumbRatio < imageRatio) {
• thumbHeight = (int)(thumbWidth / imageRatio);
• } else {
• thumbWidth = (int) (thumbHeight * imageRatio);
• }
• // draw original image to thumbnail image object and
• // scale it to the new size on-the- fly
• BufferedImage thumbImage = new BufferedImage(thumbWidth,
• thumbHeight, BufferedImage.TYPE_INT_RGB);
• Graphics2D graphics2D = thumbImage.createGraphics();
• graphics2D.setRenderingHint (RenderingHints.KEY_INTERPOLATION,
• RenderingHints.VALUE_INTERPOLATION_BILINEAR);
• graphics2D.drawImag e(image, 0, 0, thumbWidth, thumbHeight, null);
• // save thumbnail image to outFilename
• BufferedOutputStream out = new BufferedOutputStream(new
• FileOutputStream(outFilename));
• JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
• JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam
• (thumbImage);
• quality = Math.max(0, Math.min(quality, 100));
• param.setQuality((float)quality / 100.0f, false);
• encoder.setJPEGEncodeParam (param);
• encoder.encode(thumbImage);
• out.close ();
• }
  

9. 在Java中创建JSON数据

• Read this article for more details.
• Download JAR file json
• -rpc-1.0.jar (75 kb)
• import org.json.JSONObject;
• ...
• ...
• JSONObject json = new JSONObject();
• json.put("city", "Mumbai");
• json.put("country", "India");
• ...
• String output = json.toString();
• ...
  

10. 在Java中使用iText JAR打开PDF

• Read this article for more details.
• import java.io.File;
• import java.io.FileOutputStream;
• import java.io.OutputStream;
• import java.util.Date;
• import com.lowagie.text.Document;
• import com.lowagie.text.Paragraph;
• import com.lowagie.text.pdf.PdfWriter;
• public class GeneratePDF {
• public static void main(String[] args) {
• try {
• OutputStream file = new FileOutputStream(new File("C:\\Test.pdf"));
• Document document = new Document ();
• PdfWriter.getInstance(document, file);
• document.open ();
• document.add(new Paragraph("Hello Kiran"));
• document.add(new Paragraph(new Date().toString()));
• document.close ();
• file.close();
• } catch (Exception e) {
• e.printStackTrace();
• }
• }
• }
  

6.将Java中的util.Date转换成sql.Date
这一片段显示如何将一个java util Date转换成sql Date用于数据库

• java.util.Date utilDate = new java.util.Date();
• java.sql.Date sqlDate = new java.sql.Date(utilDate.getTime());
• 
  

7. 使用NIO快速复制Java文件

• public static void fileCopy( File in, File out )
• throws IOException
• {
• FileChannel inChannel = new FileInputStream( in ).getChannel ();
• FileChannel outChannel = new FileOutputStream( out ).getChannel();
• try
• {
• //          inChannel.transferTo (0, inChannel.size(), outChannel);      // original
• -- apparently has trouble copying large files on Windows
• // magic number for Windows, 64Mb - 32Kb)
• int maxCount = (64 * 1024 * 1024) - (32 * 1024);
• long size = inChannel.size ();
• long position = 0;
• while ( position < size )
• {
•   position += inChannel.transferTo( position, maxCount, outChannel );
• }
• }
• finally
• {
• if ( inChannel != null )
• {
•   inChannel.close ();
• }
• if ( outChannel != null )
• {
•    outChannel.close ();
• }
• }
• }
  

8. 在Java中创建缩略图

• private void createThumbnail(String filename, int thumbWidth, int thumbHeight, int quality, String outFilename)
• throws InterruptedException, FileNotFoundException, IOException
• {
• // load image from filename
• Image image = Toolkit.getDefaultToolkit().getImage (filename);
• MediaTracker mediaTracker = new MediaTracker(new Container());
• mediaTracker.addImage(image, 0);
• mediaTracker.waitForID(0);
• // use this to test for errors at this point: System.out.println
• (mediaTracker.isErrorAny());
• // determine thumbnail size from WIDTH and HEIGHT
• double thumbRatio = (double)thumbWidth / (double) thumbHeight;
• int imageWidth = image.getWidth (null);
• int imageHeight = image.getHeight (null);
• double imageRatio = (double)imageWidth / (double) imageHeight;
• if (thumbRatio < imageRatio) {
• thumbHeight = (int)(thumbWidth / imageRatio);
• } else {
• thumbWidth = (int) (thumbHeight * imageRatio);
• }
• // draw original image to thumbnail image object and
• // scale it to the new size on-the- fly
• BufferedImage thumbImage = new BufferedImage(thumbWidth,
• thumbHeight, BufferedImage.TYPE_INT_RGB);
• Graphics2D graphics2D = thumbImage.createGraphics();
• graphics2D.setRenderingHint (RenderingHints.KEY_INTERPOLATION,
• RenderingHints.VALUE_INTERPOLATION_BILINEAR);
• graphics2D.drawImag e(image, 0, 0, thumbWidth, thumbHeight, null);
• // save thumbnail image to outFilename
• BufferedOutputStream out = new BufferedOutputStream(new
• FileOutputStream(outFilename));
• JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
• JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam
• (thumbImage);
• quality = Math.max(0, Math.min(quality, 100));
• param.setQuality((float)quality / 100.0f, false);
• encoder.setJPEGEncodeParam (param);
• encoder.encode(thumbImage);
• out.close ();
• }
  

9. 在Java中创建JSON数据

• Read this article for more details.
• Download JAR file json
• -rpc-1.0.jar (75 kb)
• import org.json.JSONObject;
• ...
• ...
• JSONObject json = new JSONObject();
• json.put("city", "Mumbai");
• json.put("country", "India");
• ...
• String output = json.toString();
• ...
  

10. 在Java中使用iText JAR打开PDF

• Read this article for more details.
• import java.io.File;
• import java.io.FileOutputStream;
• import java.io.OutputStream;
• import java.util.Date;
• import com.lowagie.text.Document;
• import com.lowagie.text.Paragraph;
• import com.lowagie.text.pdf.PdfWriter;
• public class GeneratePDF {
• public static void main(String[] args) {
• try {
• OutputStream file = new FileOutputStream(new File("C:\\Test.pdf"));
• Document document = new Document ();
• PdfWriter.getInstance(document, file);
• document.open ();
• document.add(new Paragraph("Hello Kiran"));
• document.add(new Paragraph(new Date().toString()));
• document.close ();
• file.close();
• } catch (Exception e) {
• e.printStackTrace();
• }
• }
• }