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Tips ‘n’ Tricks |
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1. Download files data from many
URLs and save them to the local
files in the directory of your choice:
This Java program lets you download files
from one or more URLs and save them in the
directory where you want. This program takes
destination directory for the files to save as
first command line argument and URLs for
the files as next command line arguments
separated by space. Java provides
URLConnection class that represents a
communication link between the application
and a URL. Invoking the openConnection
method on a URL creates URLConnection
object. Now get InputStream object from that
connection and read the data. Finally write
the data to the local file.
FileDataDownload.java:
import java.io.*;
import java.net.*;
public class FileDataDownload {
final static int size=1024;
public static void
FileDownload(String fileAddress, String
localFileName, String destinationDir) {
OutputStream os = null;
URLConnection URLConn = null;
// URLConnection class represents a
communication link between the
// application and a URL.
InputStream is = null;
try {
URL fileUrl;
byte[] buf;
int ByteRead,ByteWritten=0;
fileUrl= new URL(fileAddress);
os = new BufferedOutputStream(new
FileOutputStream(destinationDir+”\\”+
localFileName));
//The URLConnection object is
created by invoking the
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// openConnection method on a URL.
URLConn = fileUrl.openConnection();
is = URLConn.getInputStream();
buf = new byte[size];
while ((ByteRead = is.read(buf)) != -1) {
os.write(buf, 0, ByteRead);
ByteWritten += ByteRead;
}
System.out.println(“Downloaded
Successfully.”);
System.out.println(“File name
:\””+localFileName+ “\”\nNo of
bytes :” + ByteWritten);
}
catch (Exception e) {
e.printStackTrace();
}
finally {
try {
is.close();
os.close();
}
catch (IOException e) {
e.printStackTrace();
}}} public static void fileDownload(String
fileAddress, String destinationDir)
{
// Find the index of last occurance of
character ‘/’ and ‘.’.
int lastIndexOfSlash =
fileAddress.lastIndexOf(‘/’);
int lastIndexOfPeriod =
fileAddress.lastIndexOf(‘.’);
// Find the name of file to be downloaded
from the address.
String fileName=fileAddress.substring
(lastIndexOfSlash + 1);
// Check whether path or file name is given
correctly. |
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Sept 2007 | Java Jazz Up | 65 |
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