关于java中MD5加密（可直接使用）

本文转自：http://www.cnblogs.com/solove/archive/2011/10/18/2216715.html

上部分是转载的关于字符串的加密，后半部分则比较全，包括字符串、文件、字节数组、等

package util;

import java.security.MessageDigest;

public class Encript {
    //十六进制下数字到字符的映射数组
    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);
    }

    /**
    * 验证输入的密码是否正确
    * @param password 真正的密码（加密后的真密码）
    * @param inputString 输入的字符串
    * @return 验证结果，boolean类型
    */
    public static boolean authenticatePassword(String password,String inputString){
        if(password.equals(encodeByMD5(inputString))){
            return true;
        }else{
            return false;
        }
    }

    /**对字符串进行MD5编码*/
    private static String encodeByMD5(String originString){
        if (originString!=null) {
            try {
                //创建具有指定算法名称的信息摘要
                MessageDigest md5 = MessageDigest.getInstance("MD5");
                //使用指定的字节数组对摘要进行最后更新，然后完成摘要计算
                byte[] results = md5.digest(originString.getBytes());
                //将得到的字节数组变成字符串返回
                String result = byteArrayToHexString(results);
                return result;
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    /**
    * 轮换字节数组为十六进制字符串
    * @param b 字节数组
    * @return 十六进制字符串
    */
    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();
    }

    //将一个字节转化成十六进制形式的字符串
    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加密处理工具类 * @author Administrator * */
public class MD5Utils {	/**	 * 默认的密码字符串组合，用来将字节转换成 16 进制表示的字符,apache校验下载的文件的正确性用的就是默认的这个组合	 */	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()					+ "初始化失败，MessageDigest不支持MD5Util。");			nsaex.printStackTrace();		}	}
	/**	 * 生成字符串的md5校验值	 * 	 * @param s	 * @return	 */	public static String getMD5String(String s) {		return getMD5String(s.getBytes());	}
	/**	 * 判断字符串的md5校验码是否与一个已知的md5码相匹配	 * 	 * @param password	 *            要校验的字符串	 * @param md5PwdStr	 *            已知的md5校验码	 * @return	 */	public static boolean isEqualsToMd5(String password, String md5PwdStr) {		String s = getMD5String(password);		return s.equals(md5PwdStr);	}
	/**	 * 生成文件的md5校验值	 * 	 * @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());	}
	/**	 * 生成字节数组的md5校验值	 * 	 * @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];// 取字节中高 4 位的数字转换, >>>												// 为逻辑右移，将符号位一起右移,此处未发现两种符号有何不同		char c1 = hexDigits[bt & 0xf];// 取字节中低 4 位的数字转换		stringbuffer.append(c0);		stringbuffer.append(c1);	}		/**	  * 将源字符串使用MD5加密为字节数组	  * @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;	 }
	 /**	  * 将源字符串使用MD5加密为32位16进制数	  * @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();	 }
	 /**	  * 验证字符串是否匹配	  * @param unknown 待验证的字符串	  * @param okHex 使用MD5加密过的16进制字符串	  * @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));	 }}