密码、文件MD5加密，密码sha256、sha384、sha512Hex等加密

密码、文件MD5加密，密码sha256、sha384、sha512Hex等加密

使用时请先导入commons-codec-1.5.jar包

 package com.pdsu.crm.utils;

 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.OutputStream;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;

 import org.apache.commons.codec.binary.Base64OutputStream;
 import org.apache.commons.codec.digest.DigestUtils;

 /**
  * 类说明：密码的加密与解密
  *
  * @author 作者: LiuJunGuang
  * @version 创建时间：2011-5-19 下午11:07:09
  */
 public class PasswordEncode {
     public final static String MD5 = "MD5";
     public final static String NONE = "NONE";
     public final static String SHA_256 = "SHA-256";
     public final static String SHA_512 = "SHA-512";
     public final static String SHA_384 = "SHA-384";

     /**
      * 加密文件算法
      *
      * @param filename
      *            需要加密的文件名
      * @param algorithm
      *            加密算法名
      */
     public static void digestFile(String filename, String algorithm) {
         byte[] b = new byte[1024 * 4];
         int len = 0;
         FileInputStream fis = null;
         FileOutputStream fos = null;
         try {
             MessageDigest md = MessageDigest.getInstance(algorithm);
             fis = new FileInputStream(filename);
             while ((len = fis.read(b)) != -1) {
                 md.update(b, 0, len);
             }
             byte[] digest = md.digest();
             StringBuffer fileNameBuffer = new StringBuffer(128).append(filename).append(".").append(algorithm);
             fos = new FileOutputStream(fileNameBuffer.toString());
             OutputStream encodedStream = new Base64OutputStream(fos);
             encodedStream.write(digest);
             encodedStream.flush();
             encodedStream.close();
         } catch (Exception e) {
             System.out.println("Error computing Digest: " + e);
         } finally {
             try {
                 if (fis != null)
                     fis.close();
             } catch (Exception ignored) {
             }
             try {
                 if (fos != null)
                     fos.close();
             } catch (Exception ignored) {
             }
         }
     }

     /**
      * 加密密码算法
      *
      * @param pass
      *            需要加密的原始密码
      * @param algorithm
      *            加密算法名称
      * @return 加密后的密码
      * @throws NoSuchAlgorithmException
      *             当加密算法不可用时抛出此异常
      */
     public static String digestString(String password, String alg) throws NoSuchAlgorithmException {
         String newPass;
         if (alg == null || MD5.equals(alg)) {
             newPass = DigestUtils.md5Hex(password);
         } else if (NONE.equals(alg)) {
             newPass = password;
         } else if (SHA_256.equals(alg)) {
             newPass = DigestUtils.sha256Hex(password);
         } else if (SHA_384.equals(alg)) {
             newPass = DigestUtils.sha384Hex(password);
         } else if (SHA_512.equals(alg)) {
             newPass = DigestUtils.sha512Hex(password);
         } else {
             newPass = DigestUtils.shaHex(password);
         }
         return newPass;
     }

     /**
      * 加密密码算法，默认的加密算法是MD5
      *
      * @param password
      *            未加密的密码
      * @return String 加密后的密码
      */
     public static String digestPassword(String password) {
         try {
             if (password != null && !"".equals(password)) {
                 return digestString(password, MD5);
             } else
                 return null;
         } catch (NoSuchAlgorithmException nsae) {
             throw new RuntimeException("Security error: " + nsae);
         }
     }

     /**
      * 判断密码是不是相等，默认的加密算法是MD5
      *
      * @param beforePwd
      *            要判断的密码
      * @param afterPwd
      *            加密后的数据库密码
      * @return Boolean true 密码相等
      */
     public static boolean isPasswordEnable(String beforePwd, String afterPwd) {
         if (beforePwd != null && !"".equals(beforePwd)) {
             String password = digestPassword(beforePwd);
             return afterPwd.equals(password);
         } else
             return false;
     }

     public static void main(String[] args) throws NoSuchAlgorithmException {
         System.out.println(PasswordEncode.digestPassword("123456"));
         System.out.println(PasswordEncode.digestString("123456", PasswordEncode.MD5));
         PasswordEncode.digestFile("C:\\Users\\user\\Desktop\\PasswordEncode.java", PasswordEncode.SHA_512);
         System.out.println(PasswordEncode.isPasswordEnable("123456", PasswordEncode.digestPassword("123456")));
     }
 }