JAVA用OPENSSL计算文件的SHA1值,并以BASE64格式保存

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.SimpleDateFormat;
import java.util.Date;

import sun.misc.BASE64Encoder;

public class MDCalculationTest ...{

    public MDCalculationTest(String fileName) ...{
        FileInputStream fis = null;
        BufferedInputStream bufferedInputStream = null;
        try ...{
System.out.println("programing begin....");
SimpleDateFormat df = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
System.out.println(df.format(new Date()));
            MessageDigest alga = MessageDigest.getInstance("SHA-1");

            File file = new File(fileName);
            if (!file.exists() || file.isDirectory()) ...{
                throw new FileNotFoundException("file is not exsit!");
            }
    
            fis = new FileInputStream(file);
            bufferedInputStream = new BufferedInputStream(fis);
            byte[] bt = new byte[4096];
            int tmp = 0;
            while (true) ...{
                tmp = bufferedInputStream.read(bt, 0, bt.length);                
                if (tmp < 0) ...{
                    break;
                }

                Thread.yield();
                alga.update(bt, 0, tmp);
            }
            
            byte[] digesta = alga.digest();            
            BASE64Encoder base64 = new BASE64Encoder();
            String result = base64.encode(digesta);
System.out.println("base64 encode's result is = " + result);
System.out.println(df.format(new Date()));
        } catch (NoSuchAlgorithmException e) ...{
            e.printStackTrace();
        } catch (FileNotFoundException e) ...{
            e.printStackTrace();
        } catch (IOException e) ...{
            e.printStackTrace();
        } finally ...{
            if (bufferedInputStream != null) ...{
            try ...{
                bufferedInputStream.close();
            } catch (IOException e) ...{
                e.printStackTrace();
            }
            }
        }
    }
    
    public static void main(String args[]) ...{
        if (args == null || args.length == 0) ...{
            System.out.println("please input the fullpath of an file. then excute again!");
            return;
        }
        MDCalculationTest test = new MDCalculationTest(args[0]);
    }
}