本文實(shí)例講述了Java實(shí)現(xiàn)MD5加密的方法。分享給大家供大家參考。具體實(shí)現(xiàn)方法如下：
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import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; public class MD5HashUtil { private MessageDigest md = null; private static MD5HashUtil md5 = null; private static final char[] hexChars ={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'}; /** * Constructor is private so you must use the getInstance method */ private MD5HashUtil() throws NoSuchAlgorithmException { md = MessageDigest.getInstance("MD5"); } /** * This returns the singleton instance */ public static MD5HashUtil getInstance()throws NoSuchAlgorithmException { if (md5 == null) { md5 = new MD5HashUtil(); } return (md5); } public static String hashCode(String dataToHash) throws NoSuchAlgorithmException{ return getInstance().hashData(dataToHash.getBytes()); } public static String hashCode(byte[] dataToHash) throws NoSuchAlgorithmException{ return getInstance().hashData(dataToHash); } public String hashData(byte[] dataToHash) { return hexStringFromBytes((calculateHash(dataToHash))).toLowerCase(); } private byte[] calculateHash(byte[] dataToHash) { md.update(dataToHash, 0, dataToHash.length); return (md.digest()); } public String hexStringFromBytes(byte[] b) { String hex = ""; int msb; int lsb = 0; int i; // MSB maps to idx 0 for (i = 0; i < b.length; i++) { msb = ((int)b[i] & 0x000000FF) / 16; lsb = ((int)b[i] & 0x000000FF) % 16; hex = hex + hexChars[msb] + hexChars[lsb]; } return(hex); } public static void main(String args[]) throws NoSuchAlgorithmException { String string = "my name is zhangli"; System.out.println(string); System.out.println(hashCode(string)); } } |
如上代碼為java語(yǔ)言實(shí)現(xiàn)md5加密算法，輸出為加密后的密文！
通常將加密后的密文保存在數(shù)據(jù)庫(kù)中，如果需要比較只比較他們的用md5加密過(guò)后的密文。
同時(shí)，md5加密算法是不可逆的，破解的難度很高，雖然有人破解了md5,但是他們所用的硬件環(huán)境不是我們普通的計(jì)算機(jī)所比擬的，山大的一位很牛的女教授也破解了md5,不過(guò)不怎么了解
希望本文所述對(duì)大家的java程序設(shè)計(jì)有所幫助。
