關於java中MD5加密（可直接使用）

本文轉自：http://www.cnblogs.com/solove/archive/2011/10/18/2216715.html

上部分是轉載的關於字符串的加密，后半部分則比較全，包括字符串、文件、字節數組、等

package util;

import java.security.MessageDigest;

public class Encript {
    //十六進制下數字到字符的映射數組
    private final static String[] hexDigits = {"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"};

    /**把inputString加密*/
    public static String md5(String inputStr){
        return encodeByMD5(inputStr);
    }

    /**
    * 驗證輸入的密碼是否正確
    * @param password 真正的密碼（加密后的真密碼）
    * @param inputString 輸入的字符串
    * @return 驗證結果，boolean類型
    */
    public static boolean authenticatePassword(String password,String inputString){
        if(password.equals(encodeByMD5(inputString))){
            return true;
        }else{
            return false;
        }
    }

    /**對字符串進行MD5編碼*/
    private static String encodeByMD5(String originString){
        if (originString!=null) {
            try {
                //創建具有指定算法名稱的信息摘要
                MessageDigest md5 = MessageDigest.getInstance("MD5");
                //使用指定的字節數組對摘要進行最后更新，然后完成摘要計算
                byte[] results = md5.digest(originString.getBytes());
                //將得到的字節數組變成字符串返回
                String result = byteArrayToHexString(results);
                return result;
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    /**
    * 輪換字節數組為十六進制字符串
    * @param b 字節數組
    * @return 十六進制字符串
    */
    private static String byteArrayToHexString(byte[] b){
        StringBuffer resultSb = new StringBuffer();
        for(int i=0;i<b.length;i++){
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }

    //將一個字節轉化成十六進制形式的字符串
    private static String byteToHexString(byte b){
        int n = b;
        if(n<0)
        n=256+n;
        int d1 = n/16;
        int d2 = n%16;
        return hexDigits[d1] + hexDigits[d2];
    }
}
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 package com.angsentech.ssm.util; import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.io.UnsupportedEncodingException;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException; /** * MD5加密處理工具類 * @author Administrator * */ public class MD5Utils { /** * 默認的密碼字符串組合，用來將字節轉換成 16 進制表示的字符,apache校驗下載的文件的正確性用的就是默認的這個組合 */ protected static char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };  protected static MessageDigest messagedigest = null; static { try { messagedigest = MessageDigest.getInstance("MD5"); } catch (NoSuchAlgorithmException nsaex) { System.err.println(MD5Utils.class.getName() + "初始化失敗，MessageDigest不支持MD5Util。"); nsaex.printStackTrace(); } }  /** * 生成字符串的md5校驗值 *  * @param s * @return */ public static String getMD5String(String s) { return getMD5String(s.getBytes()); }  /** * 判斷字符串的md5校驗碼是否與一個已知的md5碼相匹配 *  * @param password * 要校驗的字符串 * @param md5PwdStr * 已知的md5校驗碼 * @return */ public static boolean isEqualsToMd5(String password, String md5PwdStr) { String s = getMD5String(password); return s.equals(md5PwdStr); }  /** * 生成文件的md5校驗值 *  * @param file * @return * @throws IOException */ public static String getFileMD5String(File file) throws IOException { InputStream fis; fis = new FileInputStream(file); byte[] buffer = new byte[1024]; int numRead = 0; while ((numRead = fis.read(buffer)) > 0) { messagedigest.update(buffer, 0, numRead); } fis.close(); return bufferToHex(messagedigest.digest()); }  /** * 生成字節數組的md5校驗值 *  * @param s * @return */ public static String getMD5String(byte[] bytes) { messagedigest.update(bytes); return bufferToHex(messagedigest.digest()); }  private static String bufferToHex(byte bytes[]) { return bufferToHex(bytes, 0, bytes.length); }  private static String bufferToHex(byte bytes[], int m, int n) { StringBuffer stringbuffer = new StringBuffer(2 * n); int k = m + n; for (int l = m; l < k; l++) { appendHexPair(bytes[l], stringbuffer); } return stringbuffer.toString(); }  private static void appendHexPair(byte bt, StringBuffer stringbuffer) { char c0 = hexDigits[(bt & 0xf0) >> 4];// 取字節中高 4 位的數字轉換, >>> // 為邏輯右移，將符號位一起右移,此處未發現兩種符號有何不同 char c1 = hexDigits[bt & 0xf];// 取字節中低 4 位的數字轉換 stringbuffer.append(c0); stringbuffer.append(c1); }  /** * 將源字符串使用MD5加密為字節數組 * @param source * @return */ public static byte[] encode2bytes(String source) { byte[] result = null; try { MessageDigest md = MessageDigest.getInstance("MD5"); md.reset(); md.update(source.getBytes("UTF-8")); result = md.digest(); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); }  return result; }  /** * 將源字符串使用MD5加密為32位16進制數 * @param source * @return */ public static String encode2hex(String source) { byte[] data = encode2bytes(source); StringBuffer hexString = new StringBuffer(); for (int i = 0; i < data.length; i++) { String hex = Integer.toHexString(0xff & data[i]);  if (hex.length() == 1) { hexString.append('0'); }  hexString.append(hex); }  return hexString.toString(); }  /** * 驗證字符串是否匹配 * @param unknown 待驗證的字符串 * @param okHex 使用MD5加密過的16進制字符串 * @return 匹配返回true，不匹配返回false */ public static boolean validate(String unknown , String okHex) { return okHex.equals(encode2hex(unknown)); }}