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java.net
Class URLConnection

java.lang.Object
  extended by java.net.URLConnection
Direct Known Subclasses:
HttpURLConnection, JarURLConnection
See Also:
Top Examples, Source Code, setFileNameMap, getFileNameMap, URL.openConnection(), connect(), getContent(), getContentEncoding(), getContentLength(), getContentType(), getDate(), getExpiration(), getHeaderField(int), getHeaderField(java.lang.String), getInputStream(), getLastModified(), getOutputStream(), setAllowUserInteraction(boolean), setDefaultUseCaches(boolean), setDoInput(boolean), setDoOutput(boolean), setIfModifiedSince(long), setRequestProperty(java.lang.String, java.lang.String), setUseCaches(boolean)
public void addRequestProperty(String key,
                               String value)
See Also:
getRequestProperties(), NullPointerException, IllegalStateException
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[233]Uploading Files over URL connection
By Anonymous on 2005/06/10 01:44:38  Rate
//Uploading Files 
 String userInfo = user + ":" + password; 
 String urlString = "ftp://" + userInfo + "@" + host + "/" + file; 
 URL = new URL ( urlString ) ; 
 URLConnection urlConn = url.openConnection (  ) ; 
 OutputStream st = urlConn.getOutputStream (  ) ; 
 BufferedOutputStream ost = new BufferedOutputStream ( st, bufferSize ) ; 
 FileInputStream ist = new FileInputStream ( file ) ; 
 byte buffer [ bufferSize ] ; 
 int nBytes; 
 while (  ( nBytes = ist.read ( buffer )  )  != -1 )   {  
     ost.write ( buffer, nBytes ) ; 
  }  
  
  
  
 //addRequestProperty

[1490]Simple example of how to download a page/file/whatever from a url
By Andrew Roth (andrewroth81 { at } hot { dot } removeme { dot } mail { dot } com) on 2005/07/20 15:08:38  Rate
/**  
  * Simple example of how to download a page/file/whatever from a url.  
  * by Andrew Roth  ( andrewroth81@hot.removeme.mail.com )  
  **/ 
  
  
 import java.net.*; 
 import java.io.*; 
 import java.util.*; 
  
  
 import javax.swing.JFileChooser; 
  
  
 public class URLDownloader  {  
     private static final int MAX_BUFFER_SIZE = 8192; 
  
  
     public static void downloadURL ( HttpURLConnection u )  throws IOException  {  
         // Display the URL address, and information about it. 
         System.out.println ( u.getURL (  ) .toExternalForm (  )  + ":" ) ; 
         System.out.println ( " Content Type: " + u.getContentType (  )  ) ; 
         System.out.println ( " Content Length: " + u.getContentLength (  )  ) ; 
         System.out.println ( " Last Modified: " + new Date ( u.getLastModified (  )  )  ) ; 
         System.out.println ( " Expiration: " + u.getExpiration (  )  ) ; 
         System.out.println ( " Content Encoding: " + u.getContentEncoding (  )  ) ; 
          
         JFileChooser fileChooser = new JFileChooser (  ) ; 
         int result = fileChooser.showSaveDialog ( null ) ; 
          
         if  ( result == JFileChooser.APPROVE_OPTION )   {  
              
             // set up input stream for url 
             DataInputStream in = new DataInputStream ( u.getInputStream (  )  ) ; 
  
  
             // set up output stream 
             OutputStream out = new FileOutputStream ( fileChooser.getSelectedFile (  )  ) ; 
              
             // initialize values 
             final int size = u.getContentLength (  ) ; 
             int read = 0; 
  
  
             // create buffer 
             byte [  ]  buffer = new byte [ MAX_BUFFER_SIZE ] ; 
  
  
             while  ( read  <  size )   {  
                 if  ( in.available (  )   >  0 )   {  
                      
                     System.out.println ( "bytes available = " + in.available (  )  ) ; 
                      
                     // calculate  
                     int toRead = Math.min ( in.available (  ) , MAX_BUFFER_SIZE ) ; 
                     System.out.println ( "to read = " + toRead ) ; 
                      
                     // read from stream 
                     int readLen = in.read ( buffer ) ; 
                     read += readLen; 
                     System.out.println ( "actually read = " + readLen ) ; 
                     System.out.println ( "total read from file = " + read ) ; 
                      
                     // percentage 
                     System.out.println (  ( int )  (  ( float ) read /  ( float ) size * 100 )  + "%" ) ; 
                      
                     // write to output file 
                     out.write ( buffer, 0, readLen ) ; 
                  }  
              }  
              
             out.close (  ) ; 
             in.close (  ) ; 
          }  
      }  
      
     // Create a URL from the specified address, open a connection to it, 
     // and then display information about the URL. 
     public static void main ( String [  ]  args )   
         throws MalformedURLException, IOException 
      {  
         URL url = new URL ( args [ 0 ]  ) ; 
         HttpURLConnection connection =  ( HttpURLConnection ) url.openConnection (  ) ; 
         downloadURL ( connection ) ; 
         connection.disconnect (  ) ; 
          
         System.exit ( 0 ) ; 
      }  
  } 
protected boolean allowUserInteraction
See Also:
setDefaultAllowUserInteraction(boolean), setAllowUserInteraction(boolean), getAllowUserInteraction()
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public abstract void connect()
                      throws IOException
See Also:
setConnectTimeout(int), getConnectTimeout(), connected, SocketTimeoutException
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protected boolean connected
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protected boolean doInput
See Also:
setDoInput(boolean), getDoInput()
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protected boolean doOutput
See Also:
setDoOutput(boolean), getDoOutput()
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public boolean getAllowUserInteraction()
See Also:
setAllowUserInteraction(boolean)
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public int getConnectTimeout()
See Also:
connect(), setConnectTimeout(int)
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public Object getContent()
                  throws IOException
See Also:
setContentHandlerFactory(java.net.ContentHandlerFactory), getContentType(), ContentHandlerFactory.createContentHandler(java.lang.String), UnknownServiceException
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public Object getContent(Class[] classes)
                  throws IOException
See Also:
setContentHandlerFactory(java.net.ContentHandlerFactory), ContentHandlerFactory.createContentHandler(java.lang.String), getContent(), UnknownServiceException
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public String getContentEncoding()
See Also:
getHeaderField(java.lang.String)
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public int getContentLength()
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public String getContentType()
See Also:
getHeaderField(java.lang.String)
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public long getDate()
See Also:
getHeaderField(java.lang.String)
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public static boolean getDefaultAllowUserInteraction()
See Also:
setDefaultAllowUserInteraction(boolean)
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@Deprecated
public static String getDefaultRequestProperty(String key)
See Also:
setDefaultRequestProperty(java.lang.String, java.lang.String), getRequestProperty(java.lang.String)
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public boolean getDefaultUseCaches()
See Also:
setDefaultUseCaches(boolean)
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public boolean getDoInput()
See Also:
setDoInput(boolean)
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public boolean getDoOutput()
See Also:
setDoOutput(boolean)
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public long getExpiration()
See Also:
getHeaderField(java.lang.String)
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public static FileNameMap getFileNameMap()
See Also:
setFileNameMap(java.net.FileNameMap)
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[803]Check a URL file content type
By tcesenthil { at } yahoo { dot } com on 2005/04/05 00:34:17  Rate
 String fileName = "c:/test.txt"; 
  FileNameMap fileNameMap = URLConnection.getFileNameMap (  ) ; 
  String mimeType = fileNameMap.getContentTypeFor ( fileName ) ;
public String getHeaderField(int n)
See Also:
getHeaderFieldKey(int)
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public String getHeaderField(String name)
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public long getHeaderFieldDate(String name,
                               long Default)
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public int getHeaderFieldInt(String name,
                             int Default)
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public String getHeaderFieldKey(int n)
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public Map<String,List<String>> getHeaderFields()
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public long getIfModifiedSince()
See Also:
setIfModifiedSince(long)
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public InputStream getInputStream()
                           throws IOException
See Also:
getReadTimeout(), setReadTimeout(int), UnknownServiceException
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[767]URLConnection property
By mksvarma { at } epatra { dot } com on 2004/05/07 01:45:27  Rate
import java.net.*; 
 import java.io.*; 
 import java.util.*; 
  
  
  
 public class UrlConnection 
  {  
   public static void main ( String args [  ]  )  throws MalformedURLException 
    {  
   try {  
  
  
     URL url=new URL ( "http","localhost",80,"D://programs//Net//karthik//Demo.java" ) ; 
     URLConnection con=url.openConnection (  ) ; 
  
  
      
     System.out.println ( "Date : "+new Date ( con.getDate (  )  )  ) ; 
     System.out.println ( "Content Type : "+con.getContentType (  )  ) ; 
     System.out.println ( "Content Length : "+con.getContentLength (  )  ) ; 
      
     InputStream in=con.getInputStream (  ) ; 
     int x=1; 
     System.out.println ( "x "+x ) ; 
     int i=con.getContentLength (  ) ; 
     System.out.println ( "x "+x ) ; 
     int j=0; 
     System.out.println ( "x "+x ) ; 
     while (  ( j=in.read (  )  )  != -1 )   
      {  
       System.out.println ( "x "+x ) ; 
       System.out.print (  ( char ) j ) ; 
      }  
     System.out.println ( "x "+x ) ; 
     in.close (  ) ; 
      } catch ( Exception e )  
        {    
         System.out.println ( "Exp in catch : "+e ) ; 
        }  
  }  
  }     
public long getLastModified()
See Also:
getHeaderField(java.lang.String)
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public OutputStream getOutputStream()
                             throws IOException
See Also:
UnknownServiceException
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public Permission getPermission()
                         throws IOException
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public int getReadTimeout()
See Also:
InputStream.read(), setReadTimeout(int)
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public Map<String,List<String>> getRequestProperties()
See Also:
IllegalStateException
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public String getRequestProperty(String key)
See Also:
setRequestProperty(java.lang.String, java.lang.String), IllegalStateException
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public URL getURL()
See Also:
url
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public boolean getUseCaches()
See Also:
setUseCaches(boolean)
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public static String guessContentTypeFromName(String fname)
See Also:
getContentType()
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public static String guessContentTypeFromStream(InputStream is)
                                         throws IOException
See Also:
getContentType(), InputStream.markSupported(), InputStream.mark(int)
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protected long ifModifiedSince
See Also:
setIfModifiedSince(long), getIfModifiedSince()
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public void setAllowUserInteraction(boolean allowuserinteraction)
See Also:
getAllowUserInteraction(), IllegalStateException
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public void setConnectTimeout(int timeout)
See Also:
connect(), getConnectTimeout(), IllegalArgumentException
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public static void setContentHandlerFactory(ContentHandlerFactory fac)
See Also:
SecurityManager.checkSetFactory(), getContent(), SecurityException, Error
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public static void setDefaultAllowUserInteraction(boolean defaultallowuserinteraction)
See Also:
getDefaultAllowUserInteraction()
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@Deprecated
public static void setDefaultRequestProperty(String key,
                                                        String value)
See Also:
getDefaultRequestProperty(java.lang.String), setRequestProperty(java.lang.String,java.lang.String)
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public void setDefaultUseCaches(boolean defaultusecaches)
See Also:
getDefaultUseCaches()
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public void setDoInput(boolean doinput)
See Also:
getDoInput(), doInput, IllegalStateException
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public void setDoOutput(boolean dooutput)
See Also:
getDoOutput(), IllegalStateException
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[1737]How do I access Servlets or CGI programs from Java?
By Anonymous on 2006/03/30 07:04:14  Rate
Using the QUERY method  ( i.e., the calling parameters encoded in the URL ) , it is simple to access Servlets or CGI programs from Java: 
  
  
 URLConnection connect  (  new URL ( "http:\\me\mycgi.sh" )   ) .getConnection (  ) ; 
 PrintStream ps = new PrintStream ( connect.getOutputStream (  )  ) ; 
 connection.setdoOutput ( true ) // defaults to false 
 ps.print ( myPostData ) ; 
 ps.close (  )  // very important to close before reading 
 InputStream is = new PrintStream ( connect.getInputStream (  )  ) ; 
 // read the results 
  
  
 NOTE: URLConnection (  )  is an abstract class whose sub-class is usually supplied by the environment  ( browser ) . Some browsers allow output without calling "doOutput ( true ) ," which violates the Java spec and may be confusing when code works in one place and not the other.
public static void setFileNameMap(FileNameMap map)
See Also:
getFileNameMap(), SecurityManager.checkSetFactory(), SecurityException
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public void setIfModifiedSince(long ifmodifiedsince)
See Also:
getIfModifiedSince(), IllegalStateException
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public void setReadTimeout(int timeout)
See Also:
InputStream.read(), getReadTimeout(), IllegalArgumentException
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public void setRequestProperty(String key,
                               String value)
See Also:
getRequestProperty(java.lang.String), NullPointerException, IllegalStateException
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public void setUseCaches(boolean usecaches)
See Also:
getUseCaches(), IllegalStateException
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public String toString()
See Also:
Object
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protected URL url
See Also:
getURL()
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protected URLConnection(URL url)
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protected boolean useCaches
See Also:
setDefaultUseCaches(boolean), getUseCaches(), setUseCaches(boolean)
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