20个开发人员非常有用的Java功能代码

Updated: Thanks Simone for pointing to exception. I have 

changed the code.  
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();   


    }   
}  


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();
 }
}

  
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();
 }
}

 
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 )   


            

{   


             &

nbsp; position += inChannel.transferTo( position, maxCount, outChannel );  


 
            }

   
        }   


        finally  


        {   


            if ( 

inChannel != null )   


            

{   


             &

nbsp; inChannel.close();   


            }

   
            

if ( outChannel != null )   


            

{   


             &

nbsp;  outChannel.close();   


            }

   
        }   


    }  

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

();
            }


        }
    }

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

();
 }

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();
...

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();
        }


    }
}

System.getProperties().put("http.proxyHost", 

"someProxyURL");   
System.getProperties().put("http.proxyPort", 

"someProxyPort");   
System.getProperties().put("http.proxyUser", 

"someUserName");   
System.getProperties().put("http.proxyPassword", 

"somePassword");  


System.getProperties().put("http.proxyHost", 

"someProxyURL");
System.getProperties().put("http.proxyPort", 

"someProxyPort");
System.getProperties().put("http.proxyUser", 

"someUserName");
System.getProperties().put("http.proxyPassword", 

"somePassword");

Read this article for more 

details.
Update: Thanks Markus for the comment. I have updated the code and 

changed it to 

more robust implementation.

  
public class SimpleSingleton {   
    

private static SimpleSingleton singleInstance =  new SimpleSingleton

();   
  
    //Marking default constructor 

private   
    //to avoid direct 

instantiation.   
    private SimpleSingleton() 

{   
    }   
  


    //Get instance for class SimpleSingleton   


    public static SimpleSingleton getInstance() {   


  
        return 

singleInstance;   
    }   
}  

public class SimpleSingleton {
 private static SimpleSingleton 

singleInstance =  new SimpleSingleton();
 //Marking default constructor private
 //to avoid direct 

instantiation.
 private SimpleSingleton() {
 }
 //Get instance for class SimpleSingleton
 public static 

SimpleSingleton getInstance() {
  return singleInstance;
 }
}
One more implementation of 

Singleton class. Thanks to Ralph and Lukasz Zielinski 
for pointing this out.

  
public enum SimpleSingleton {   
    

INSTANCE;   
    public void doSomething() 

{   
    }   
}   
  


//Call the method from Singleton:   


SimpleSingleton.INSTANCE.doSomething();  

public enum SimpleSingleton {
 INSTANCE;
 public void 

doSomething() {
 }
}
//Call the method from Singleton:
SimpleSingleton.INSTANCE.doSomething();

Read this article for more details.
 
import 

java.awt.Dimension;   
import java.awt.Rectangle;   


import java.awt.Robot;   
import java.awt.Toolkit;   


import java.awt.image.BufferedImage;   
import 

javax.imageio.ImageIO;   
import java.io.File;   
  


...   
  
public void captureScreen(String fileName) 

throws Exception {   
  
   Dimension screenSize = 

Toolkit.getDefaultToolkit().getScreenSize();   
   Rectangle 

screenRectangle = new Rectangle(screenSize);   
   Robot 

robot = new Robot();   
   BufferedImage image = 

robot.createScreenCapture(screenRectangle);   
   

ImageIO.write(image, "png", new File(fileName));   
  
}

   
...  

import java.awt.Dimension;
import java.awt.Rectangle;
import 

java.awt.Robot;
import java.awt.Toolkit;
import 

java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import 

java.io.File;
...
public void captureScreen(String fileName) throws Exception {
   Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize

();
   Rectangle screenRectangle = new Rectangle

(screenSize);
   Robot robot = new Robot();
   

BufferedImage image = robot.createScreenCapture(screenRectangle);
   

ImageIO.write(image, "png", new File(fileName));
}
...

>File dir = new File("directoryName");   


  String[] children = dir.list();   
  if (children == 

null) {   
      // Either dir does not exist 

or is not a directory   
  } else {   


      for (int i=0; i < children.length; i++) 

{   
          // Get 

filename of file or directory   


          String filename = 

children[i];   
      }   


  }   
  
  // It is also possible to filter the 

list of returned files.   
  // This example does not return any 

files that start with `.'.   
  FilenameFilter filter = new 

FilenameFilter() {   
      public boolean 

accept(File dir, String name) {   


          return !name.startsWith

(".");   
      }   
  

};   
  children = dir.list(filter);   
  


  // The list of files can also be retrieved as File objects   


  File[] files = dir.listFiles();   
  
  // 

This filter only returns directories   
  FileFilter fileFilter = 

new FileFilter() {   
      public boolean 

accept(File file) {   


          return file.isDirectory

();   
      }   
  

};   
  files = dir.listFiles(fileFilter);  


  File dir = new File("directoryName");
    String[] 

children = dir.list();
    if (children == null) 

{
        // Either dir does not exist or is 

not a directory
    } else 

{
        for (int i=0; i < 

children.length; i++) 

{
            // Get 

filename of file or 

directory
            

String filename = children[i];
        }


    }
    // It is also possible to filter the list of returned 

files.
    // This example does not return any files that start 

with `.'.
    FilenameFilter filter = new FilenameFilter() 

{
        public boolean accept(File dir, 

String name) 

{
            return !

name.startsWith(".");
        }


    };
    children = dir.list(filter);
    // The list of files can also be retrieved as File 

objects
    File[] files = dir.listFiles();
    // This filter only returns directories
    

FileFilter fileFilter = new FileFilter() 

{
        public boolean accept(File file) 

{
            return 

file.isDirectory();
        }


    };
    files = dir.listFiles

(fileFilter);

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<?xml version="1.0"?>  
<students>  
    <student>  
        <name>John</name>  
        <grade>B</grade>  
        <age>12</age>  
    </student>  
    <student>  
        <name>Mary</name>  
        <grade>A</grade>  
        <age>11</age>  
    </student>  
    <student>  
        <name>Simon</name>  
        <grade>A</grade>  
        <age>18</age>  
    </student>  
</students>  


<?xml version="1.0"?>
<students>
 <student>
  <name>John</name>
  <grade>B</grade>
  <age>12</age>
 </student>
 <student>
  <name>Mary</name>
  <grade>A</grade>
  <age>11</age>
 </student>
 <student>
  <name>Simon</name>
  <grade>A</grade>
  <age>18</age>
 </student>
</students>
Java code to parse above XML.
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package net.viralpatel.java.xmlparser;   
  
import java.io.File;   
import javax.xml.parsers.DocumentBuilder;   
import javax.xml.parsers.DocumentBuilderFactory;   
  
import org.w3c.dom.Document;   
import org.w3c.dom.Element;   
import org.w3c.dom.Node;   
import org.w3c.dom.NodeList;   
  
public class XMLParser {   
  
    public void getAllUserNames(String fileName) {   
        try {   
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();   
            DocumentBuilder db = dbf.newDocumentBuilder();   
            File file = new File(fileName);   
            if (file.exists()) {   
                Document doc = db.parse(file);   
                Element docEle = doc.getDocumentElement();   
  
                // Print root element of the document   
                System.out.println("Root element of the document: "  
                        + docEle.getNodeName());   
  
                NodeList studentList = docEle.getElementsByTagName("student");   
  
                // Print total student elements in document   
                System.out   
                        .println("Total students: " + studentList.getLength());   
  
                if (studentList != null && studentList.getLength() > 0) {   
                    for (int i = 0; i < studentList.getLength(); i++) {   
  
                        Node node = studentList.item(i);   
  
                        if (node.getNodeType() == Node.ELEMENT_NODE) {   
  
                            System.out   
                                    .println("=====================");   
  
                            Element e = (Element) node;   
                            NodeList nodeList = e.getElementsByTagName("name");   
                            System.out.println("Name: "  
                                    + nodeList.item(0).getChildNodes().item(0)   
                                            .getNodeValue());   
  
                            nodeList = e.getElementsByTagName("grade");   
                            System.out.println("Grade: "  
                                    + nodeList.item(0).getChildNodes().item(0)   
                                            .getNodeValue());   
  
                            nodeList = e.getElementsByTagName("age");   
                            System.out.println("Age: "  
                                    + nodeList.item(0).getChildNodes().item(0)   
                                            .getNodeValue());   
                        }   
                    }   
                } else {   
                    System.exit(1);   
                }   
            }   
        } catch (Exception e) {   
            System.out.println(e);   
        }   
    }   
    public static void main(String[] args) {   
  
        XMLParser parser = new XMLParser();   
        parser.getAllUserNames("c:\\test.xml");   
    }   
}  

package net.viralpatel.java.xmlparser;
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class XMLParser {
 public void getAllUserNames(String fileName) {
  try {
   DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
   DocumentBuilder db = dbf.newDocumentBuilder();
   File file = new File(fileName);
   if (file.exists()) {
    Document doc = db.parse(file);
    Element docEle = doc.getDocumentElement();
    // Print root element of the document
    System.out.println("Root element of the document: "
      + docEle.getNodeName());
    NodeList studentList = docEle.getElementsByTagName("student");
    // Print total student elements in document
    System.out
      .println("Total students: " + studentList.getLength());
    if (studentList != null && studentList.getLength() > 0) {
     for (int i = 0; i < studentList.getLength(); i++) {
      Node node = studentList.item(i);
      if (node.getNodeType() == Node.ELEMENT_NODE) {
       System.out
         .println("=====================");
       Element e = (Element) node;
       NodeList nodeList = e.getElementsByTagName("name");
       System.out.println("Name: "
         + nodeList.item(0).getChildNodes().item(0)
           .getNodeValue());
       nodeList = e.getElementsByTagName("grade");
       System.out.println("Grade: "
         + nodeList.item(0).getChildNodes().item(0)
           .getNodeValue());
       nodeList = e.getElementsByTagName("age");
       System.out.println("Age: "
         + nodeList.item(0).getChildNodes().item(0)
           .getNodeValue());
      }
     }
    } else {
     System.exit(1);
    }
   }
  } catch (Exception e) {
   System.out.println(e);
  }
 }
 public static void main(String[] args) {
  XMLParser parser = new XMLParser();
  parser.getAllUserNames("c:\\test.xml");
 }
}

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import java.util.Map;   
import org.apache.commons.lang.ArrayUtils;   
  
public class Main {   
  
  public static void main(String[] args) {   
    String[][] countries = { { "United States", "New York" }, { "United Kingdom", "London" },   
        { "Netherland", "Amsterdam" }, { "Japan", "Tokyo" }, { "France", "Paris" } };   
  
    Map countryCapitals = ArrayUtils.toMap(countries);   
  
    System.out.println("Capital of Japan is " + countryCapitals.get("Japan"));   
    System.out.println("Capital of France is " + countryCapitals.get("France"));   
  }   
}  


import java.util.Map;
import org.apache.commons.lang.ArrayUtils;
public class Main {
  public static void main(String[] args) {
    String[][] countries = { { "United States", "New York" }, { "United Kingdom", "London" },
        { "Netherland", "Amsterdam" }, { "Japan", "Tokyo" }, { "France", "Paris" } };
    Map countryCapitals = ArrayUtils.toMap(countries);
    System.out.println("Capital of Japan is " + countryCapitals.get("Japan"));
    System.out.println("Capital of France is " + countryCapitals.get("France"));
  }
}

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import javax.mail.*;   
import javax.mail.internet.*;   
import java.util.*;   
  
public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException   
{   
    boolean debug = false;   
  
     //Set the host smtp address   
     Properties props = new Properties();   
     props.put("mail.smtp.host", "smtp.example.com");   
  
    // create some properties and get the default Session   
    Session session = Session.getDefaultInstance(props, null);   
    session.setDebug(debug);   
  
    // create a message   
    Message msg = new MimeMessage(session);   
  
    // set the from and to address   
    InternetAddress addressFrom = new InternetAddress(from);   
    msg.setFrom(addressFrom);   
  
    InternetAddress[] addressTo = new InternetAddress[recipients.length];   
    for (int i = 0; i < recipients.length; i++)   
    {   
        addressTo[i] = new InternetAddress(recipients[i]);   
    }   
    msg.setRecipients(Message.RecipientType.TO, addressTo);   
  
    // Optional : You can also set your custom headers in the Email if you Want   
    msg.addHeader("MyHeaderName", "myHeaderValue");   
  
    // Setting the Subject and Content Type   
    msg.setSubject(subject);   
    msg.setContent(message, "text/plain");   
    Transport.send(msg);   
}  


import javax.mail.*;
import javax.mail.internet.*;
import java.util.*;
public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException
{
    boolean debug = false;
     //Set the host smtp address
     Properties props = new Properties();
     props.put("mail.smtp.host", "smtp.example.com");
    // create some properties and get the default Session
    Session session = Session.getDefaultInstance(props, null);
    session.setDebug(debug);
    // create a message
    Message msg = new MimeMessage(session);
    // set the from and to address
    InternetAddress addressFrom = new InternetAddress(from);
    msg.setFrom(addressFrom);
    InternetAddress[] addressTo = new InternetAddress[recipients.length];
    for (int i = 0; i < recipients.length; i++)
    {
        addressTo[i] = new InternetAddress(recipients[i]);
    }
    msg.setRecipients(Message.RecipientType.TO, addressTo);
    // Optional : You can also set your custom headers in the Email if you Want
    msg.addHeader("MyHeaderName", "myHeaderValue");
    // Setting the Subject and Content Type
    msg.setSubject(subject);
    msg.setContent(message, "text/plain");
    Transport.send(msg);
}

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import java.io.BufferedReader;   
import java.io.InputStreamReader;   
import java.net.URL;   
  
public class Main {   
    public static void main(String[] args)  {   
        try {   
            URL my_url = new URL("http://www.viralpatel.net/blogs/");   
            BufferedReader br = new BufferedReader(new InputStreamReader(my_url.openStream()));   
            String strTemp = "";   
            while(null != (strTemp = br.readLine())){   
            System.out.println(strTemp);   
        }   
        } catch (Exception ex) {   
            ex.printStackTrace();   
        }   
    }   
}  


import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
public class Main {
 public static void main(String[] args)  {
  try {
   URL my_url = new URL("http://www.viralpatel.net/blogs/");
   BufferedReader br = new BufferedReader(new InputStreamReader(my_url.openStream()));
   String strTemp = "";
   while(null != (strTemp = br.readLine())){
   System.out.println(strTemp);
  }
  } catch (Exception ex) {
   ex.printStackTrace();
  }
 }
}

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/**  
* Reallocates an array with a new size, and copies the contents  
* of the old array to the new array.  
* @param oldArray  the old array, to be reallocated.  
* @param newSize   the new array size.  
* @return          A new array with the same contents.  
*/  
private static Object resizeArray (Object oldArray, int newSize) {   
   int oldSize = java.lang.reflect.Array.getLength(oldArray);   
   Class elementType = oldArray.getClass().getComponentType();   
   Object newArray = java.lang.reflect.Array.newInstance(   
         elementType,newSize);   
   int preserveLength = Math.min(oldSize,newSize);   
   if (preserveLength > 0)   
      System.arraycopy (oldArray,0,newArray,0,preserveLength);   
   return newArray;   
}   
  
// Test routine for resizeArray().   
public static void main (String[] args) {   
   int[] a = {1,2,3};   
   a = (int[])resizeArray(a,5);   
   a[3] = 4;   
   a[4] = 5;   
   for (int i=0; i<a.length; i++)   
      System.out.println (a[i]);   
}