Extracting Files From A Zip File

Here’s a code snippet demonstrating how to download a zip file and extract the files contained within.

The variable zip_url_string represents the URL to download the zip file from. To read in each file, put your code after the BufferedReader statement.

 * Our first task is to grab the file, and open up a ZipInputStream to decompress the file.
 * A ZipEntry processes each entry within the ZipInputStream.
URL url_addr = new URL(zip_url_string);
HttpURLConnection con = (HttpURLConnection)url_addr.openConnection();
InputStream fis = con.getInputStream();
ZipInputStream zis = new ZipInputStream(fis);
ZipEntry entry = zis.getNextEntry();
 * We are going to loop through each ZipEntry until we get to a null entry (which 
 * represents the end of the ZipEntry list within the ZipInputStream).
while (entry != null) {
    //Collect the entry name. This is the filename, including any directory information.
    //Do any validation or processing needed.
    String entry_name = entry.getName().trim();
    //Create a BufferedReader to read in the contents of this file contained within the zip.
    InputStreamReader isr = new InputStreamReader(zis);
    BufferedReader reader = new BufferedReader(isr);
     * Do something here with the file. Use BufferedReader to read it in, then  
     * process it as necessary.
    //Grab the next entry for processing
    entry = zis.getNextEntry();
}//end while loop going through ZipEntry entries

If the zip file being downloaded is especially large, you may want to add a longer timeout:


Remember to add the appropriate import statements:

import java.net.URL;
import java.net.HttpURLConnection;
import java.io.InputStream;
import java.util.zip.*;