MD5Utils 简单计算MD5

import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.util.HashMap; import java.util.Map; import java.util.concurrent.locks.ReentrantLock; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * 简单计算MD5 */ public class MD5Utils { private static final Log log = LogFactory.getLog(MD5Utils.class); private static char[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; private static Map<Character, Integer> rDigits = new HashMap<Character, Integer>(16); static { for (int i = 0; i < digits.length; ++i) { rDigits.put(digits[i], i); } } private static MD5Utils me = new MD5Utils(); private MessageDigest mHasher; private ReentrantLock opLock = new ReentrantLock(); private MD5Utils(){ try { mHasher = MessageDigest.getInstance("md5"); } catch (Exception e) { throw new RuntimeException(e); } } public static MD5Utils getInstance() { return me; } public String getMD5String(String content) { return bytes2string(hash(content)); } public String getMD5String(byte[] content) { return bytes2string(hash(content)); } public byte[] getMD5Bytes(byte[] content) { return hash(content); } /** * 对字符串进行md5 * * @param str * @return md5 byte[16] */ public byte[] hash(String str) { opLock.lock(); try { byte[] bt = mHasher.digest(str.getBytes("UTF-8")); if (null == bt || bt.length != 16) { throw new IllegalArgumentException("md5 need"); } return bt; } catch (UnsupportedEncodingException e) { throw new RuntimeException("unsupported utf-8 encoding", e); } finally { opLock.unlock(); } } /** * 对二进制数据进行md5 * * @param str * @return md5 byte[16] */ public byte[] hash(byte[] data) { opLock.lock(); try { byte[] bt = mHasher.digest(data); if (null == bt || bt.length != 16) { throw new IllegalArgumentException("md5 need"); } return bt; } finally { opLock.unlock(); } } /** * 将一个字节数组转化为可见的字符串 * * @param bt * @return */ public String bytes2string(byte[] bt) { int l = bt.length; char[] out = new char[l << 1]; for (int i = 0, j = 0; i < l; i++) { out[j++] = digits[(0xF0 & bt[i]) >>> 4]; out[j++] = digits[0x0F & bt[i]]; } if (log.isDebugEnabled()) { log.debug("[hash]" + (new String(out))); } return new String(out); } /** * 将字符串转换为bytes * * @param str * @return byte[] */ public byte[] string2bytes(String str) { if (null == str) { throw new IllegalArgumentException("str is null"); } if (str.length() != 32) { throw new IllegalArgumentException("str.length() != 32"); } byte[] data = new byte[16]; char[] chs = str.toCharArray(); for (int i = 0; i < 16; ++i) { int h = rDigits.get(chs[i * 2]).intValue(); int l = rDigits.get(chs[i * 2 + 1]).intValue(); data[i] = (byte) ((h & 0x0F) << 4 | (l & 0x0F)); } return data; } }