Md5Encode.java

package com.xinxin.everyxday.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Md5Encode {

    // 用来将字节转换成 16 进制表示的字符   
//    static char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8',   
//            '9', 'a', 'b', 'c', 'd', 'e', 'f' };   
//    static char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8',   
//        '9', 'A', 'B', 'C', 'D', 'E', 'F' };   
    /** */  
    /**  
     * 对文件全文生成MD5摘要  
     * @param file   要加密的文件  
     * @return MD5摘要码  
     */  
    public static String getMD5(File file) {   
        FileInputStream fis = null;   
        try {   
            MessageDigest md = MessageDigest.getInstance("MD5");   
  
            fis = new FileInputStream(file);   
            byte[] buffer = new byte[2048];   
            int length = -1;   
            while ((length = fis.read(buffer)) != -1) {   
                md.update(buffer, 0, length);   
            }   
            byte[] b = md.digest();   
            return byteToHexStringSingle(b);//byteToHexString(b);   
            // 16位加密   
            // return buf.toString().substring(8, 24);   
        } catch (Exception ex) {   
//            logger.error(ex);   
            ex.printStackTrace();   
            return null;   
        } finally {   
            try {   
                fis.close();   
            } catch (IOException ex) {   
                ex.printStackTrace();   
            }   
        }   
    }   
  
    /** */  
    /**  
     * 对一段String生成MD5加密信息  
     * @param message 要加密的String  
     * @return 生成的MD5信息  
     */  
    public static String getMD5(String message) {   
    	MessageDigest md = null;
    	byte[] b = null;
        try {   
            md = MessageDigest.getInstance("MD5");   
            b = md.digest(message.getBytes("utf-8")); 
            String digestCode = byteToHexStringSingle(b);
            return digestCode;
        } catch (NoSuchAlgorithmException e) {   
            e.printStackTrace();   
        } catch (UnsupportedEncodingException e) {   
            e.printStackTrace();   
        }finally{
        	b = null;
        	md = null;
        }
        return null;   
    }   
  
    /**  
     * 独立把byte[]数组转换成十六进制字符串表示形式  
     * @author Bill  
     * @create 2010-2-24 下午03:26:53  
     * @since   
     * @param byteArray  
     * @return  
     */  
    public static String byteToHexStringSingle(byte[] byteArray) {   
        StringBuffer md5StrBuff = new StringBuffer();   
  
        for (int i = 0; i < byteArray.length; i++) {   
            if (Integer.toHexString(0xFF & byteArray[i]).length() == 1)   
                md5StrBuff.append("0").append(   
                        Integer.toHexString(0xFF & byteArray[i]));   
            else  
                md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));   
        }   
  
        return md5StrBuff.toString();   
    }   
  
    /**  
     * @author Bill  
     * @create 2010-2-24 下午03:04:53  
     * @since  
     * @param args  
     */  
    public static void main(String[] args) {   
    }   

}