package com.youtu.sign; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.security.MessageDigest; public class MD5 { public static String stringToMD5(String str) { try { byte[] strTemp = str.getBytes(); MessageDigest mdTemp = MessageDigest.getInstance("MD5"); mdTemp.update(strTemp); return toHexString(mdTemp.digest()); } catch (Exception e) { return null; } } public static String fileNameToMD5(String fileName) { InputStream inputStream = null; try { inputStream = new FileInputStream(fileName); return streamToMD5(inputStream); } catch (Exception e) { return null; } finally { if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } } } public static String streamToMD5(InputStream inputStream) { try { MessageDigest mdTemp = MessageDigest.getInstance("MD5"); byte[] buffer = new byte[1024]; int numRead = 0; while ((numRead = inputStream.read(buffer)) > 0) { mdTemp.update(buffer, 0, numRead); } return toHexString(mdTemp.digest()); } catch (Exception e) { return null; } } private static String toHexString(byte[] md) { char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; int j = md.length; char str[] = new char[j * 2]; for (int i = 0; i < j; i++) { byte byte0 = md[i]; str[2 * i] = hexDigits[byte0 >>> 4 & 0xf]; str[i * 2 + 1] = hexDigits[byte0 & 0xf]; } return new String(str); } }