File Digest

Main.java

package filedigest;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.math.BigInteger;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import javax.swing.JFileChooser;

public class Main extends javax.swing.JFrame {

    public Main() {
        initComponents();
    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        fileChooser = new javax.swing.JFileChooser();
        jButton1 = new javax.swing.JButton();
        filename = new javax.swing.JLabel();
        sum = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        getContentPane().setLayout(new java.awt.GridLayout(0, 1));

        jButton1.setText("Otwórz");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });
        getContentPane().add(jButton1);
        getContentPane().add(filename);
        getContentPane().add(sum);

        pack();
    }// </editor-fold>

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        if (JFileChooser.APPROVE_OPTION == fileChooser.showOpenDialog(this)) {
            File file = fileChooser.getSelectedFile();
            try {
                MessageDigest digest = MessageDigest.getInstance("MD5");
                InputStream is = new DigestInputStream(new FileInputStream(file), digest);
                byte[] b = new byte[128];
                while (is.read(b) != -1) {
                }
                is.close();
                BigInteger bigInt = new BigInteger(1, digest.digest());
                String hashtext = bigInt.toString(16);
                filename.setText(file.getName());
                sum.setText(hashtext);
            } catch (Exception ex) {
                System.out.println(ex);
            }
        }
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Main().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JFileChooser fileChooser;
    private javax.swing.JLabel filename;
    private javax.swing.JButton jButton1;
    private javax.swing.JLabel sum;
    // End of variables declaration
}