sha1加密java代码

public static String getSha1(String str){ if(str==null||str.length()==0){ return null; } char hexDigits[] = {'0','1','2','3','4','5','6','7','8','9', 'a','b','c','d','e','f'}; try { MessageDigest mdTemp = MessageDigest.getInstance("SHA1"); mdTemp.update(str.getBytes("UTF-8")); byte[] md = mdTemp.digest(); int j = md.length; char buf[] = new char[j*2]; int k = 0; for (int i = 0; i < j; i++) { byte byte0 = md[i]; buf[k++] = hexDigits[byte0 >>> 4 & 0xf]; buf[k++] = hexDigits[byte0 & 0xf]; } return new String(buf); } catch (Exception e) { // TODO: handle exception return null; } }