love3400windµÄblog

1. °ÑStringsת»»³ÉintºÍ°Ñintת»»³ÉString

String a = String.valueOf(2); 
//integer to numeric string  
int i = Integer.parseInt(a); //numeric string to an int 

2. ÏòJavaÎļþÖÐÌí¼ÓÎı¾

BufferedWriter out = null;  
try {  
 out = new BufferedWriter(new FileWriter(¡±filename¡±, true));  
 out.write(¡±aString¡±);  
} catch (IOException e) {
 // error processing code  
} finally{  
 if (out != null) {
  out.close();
 }  
}

3. »ñÈ¡JavaÏÖÔÚÕýµ÷Óõķ½·¨Ãû

String methodName =
Thread.currentThread().getStackTrace()[1].getMethodName(); 

4. ÔÚJavaÖн«StringÐÍת»»³ÉDateÐÍ

java.util.Date = java.text.DateFormat.getDateInstance().parse(date String); 

java.util.Date = java.text.DateFormat.getDateInstance().parse(date
String);or 
SimpleDateFormat format = new SimpleDateFormat( "dd.MM.yyyy"
);  
Date date = format.parse( myString ); 
SimpleDateFormat format = new SimpleDateFormat( "dd.MM.yyyy" );
Date date= format.parse( myString );

5. ͨ¹ýJava JDBCÁ´½ÓOracleÊý¾Ý¿â

public class OracleJdbcTest  
{  
String driverClass =

"oracle.jdbc.driver.OracleDriver";  

Connection con;  

public void init

(FileInputStream fs) throws ClassNotFoundException,

SQLException, FileNotFoundException, IOException  


{  
Properties props = new Properties();  


props.load(fs);  


String url = props.getProperty

("db.url");  
String

userName = props.getProperty("db.user");  


String password = props.getProperty

("db.password");  
Class.forName(driverClass);  

con=DriverManager.getConnection(url,

userName, password);  
}  

public void fetch() throws SQLException,

IOException  
{  


PreparedStatement ps =

con.prepareStatement("select SYSDATE from dual");  


ResultSet rs = ps.executeQuery

();  

while

(rs.next())  
{  


// do the

thing you do  
}

  
rs.close();  


ps.close();  


}  

public

static void main(String[] args)  
{  


OracleJdbcTest test = new

OracleJdbcTest();  
test.init();  
test.fetch

();  
}  
} 

public class OracleJdbcTest
{
String driverClass =

"oracle.jdbc.driver.OracleDriver";

Connection con;

public void init(FileInputStream fs) throws ClassNotFoundException,

SQLException, FileNotFoundException, IOException
{
Properties props = new Properties();
props.load

(fs);
String url = props.getProperty

("db.url");
String userName = props.getProperty

("db.user");
String password = props.getProperty

("db.password");
Class.forName(driverClass);

con=DriverManager.getConnection(url, userName,

password);
}

public void fetch() throws SQLException, IOException
{
PreparedStatement ps = con.prepareStatement("select SYSDATE from

dual");
ResultSet rs = ps.executeQuery();

while (rs.next())
{
// do the

thing you do
}
rs.close();
ps.close

();
}

public static void main(String[] args)
{
OracleJdbcTest test = new OracleJdbcTest

();
test.init();
test.fetch();
}
}

6.½«JavaÖеÄutil.Dateת»»³Ésql.Date

ÕâһƬ¶ÎÏÔʾÈçºÎ½«Ò»¸öjava util Dateת»»³Ésql DateÓÃÓÚÊý¾Ý¿â

java.util.Date utilDate = new   java.util.Date();   
java.sql.Date sqlDate = new java.sql.Date  (utilDate.getTime());  
java.util.Date utilDate = new java.util.Date();
java.sql.Date sqlDate =   new java.sql.Date(utilDate.getTime());
7. ʹÓÃNIO¿ìËÙ¸´ÖÆJavaÎļþ
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.drawImage(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    ();   
}  
  

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. ÔÚJavaÖд´½¨JSONÊý¾Ý
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    ();   
...  
  

import org.json.JSONObject;
...
...
JSONObject json = new     JSONObject();
json.put("city", "Mumbai");
json.put("country",     "India");
...
String output = json.toString();
...
10. ÔÚJavaÖÐʹÓÃiText JAR´ò¿ªPDF 
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();   
}       
}   
}  
  

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();
}    
}
}
11. ÔÚJavaÉϵÄHTTP´úÀíÉèÖÃ
 
 
Ô´ÎÄÁ´½Ó£ºhttp://developer.51cto.com/art/200905/124291_1.htm