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/* Extract File With CRC32 Checksum Example This Java example shows how to extract zip file with CRC32 Checksum using CheckedInputStream and CRC32 classes. */ import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.util.zip.CRC32; import java.util.zip.CheckedInputStream; import java.util.zip.ZipEntry; import java.util.zip.ZipInputStream; public class ExtractZipWithCRC32Checksum { public static void main(String args[]) { String sourceZipFile = "C:/FileIO/sourceFile.zip"; try { //create FileInputStream from the source zip file FileInputStream fin = new FileInputStream(sourceZipFile); /* * To extract zip file with CRC32 checksum, use * * CheckedInputStream(InputStream in, Checksum checksum) * * Constructor. */ //create CheckedInputStream object. CheckedInputStream checksum = new CheckedInputStream(fin,new CRC32()); //create ZipInputStream from CheckedInputStream object ZipInputStream zin = new ZipInputStream(checksum); //get the first entry from the source zip file ZipEntry entry = zin.getNextEntry(); //crate OutputStream to extract the entry from zip file OutputStream os = new FileOutputStream("c:/extractedFile.css"); byte[] buffer = new byte[1024]; int length; //read the entry from zip file and extract it to disk while( (length = zin.read(buffer)) > 0) { os.write(buffer, 0, length); } //close the streams os.close(); //close the zip file zin.close(); System.out.println("File Extracted from zip file"); /* * To get the CRC32 checksum of the extracted file, use * * Checksum getChecksum() * * Method of CheckedInputStream class. */ System.out.println("CRC32 checksum is: " + checksum.getChecksum().getValue()); } catch(IOException e) { System.out.println("IOException :" + e); } } } /* Output of this example would be File Extracted from zip file CRC32 checksum is: 2920622546 */ |
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