packagecom.bstek.tools;importjava.io.FileInputStream;importjava.io.IOException;importjava.security.DigestInputStream;importjava.security.MessageDigest;importjava.security.NoSuchAlgorithmException;/*** Md5
* 提供对字符串的md5-->stringMD5
* 提供对文件的Md5-->fileMD5
*
* 对于大文件，可以使用DigestInputStream*/
public classMd5Utils {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{//拿到一个MD5转换器(如果想要SHA1参数换成”SHA1”)
messageDigest = MessageDigest.getInstance("MD5");
}catch(NoSuchAlgorithmException e) {
System.err.println(Md5Utils.class.getName()+"初始化失败，MessageDigest不支持MD5Util.");
e.printStackTrace();
}
}private static String bufferToHex(byte bytes[], int m, intn) {
StringBuffer stringbuffer= new StringBuffer(2 *n);int k = m +n;for (int l = m; l < k; l++) {
appendHexPair(bytes[l], stringbuffer);
}returnstringbuffer.toString();
}private static void appendHexPair(bytebt, StringBuffer stringbuffer) {char c0 = hexDigits[(bt & 0xf0) >> 4];char c1 = hexDigits[bt & 0xf];
stringbuffer.append(c0);
stringbuffer.append(c1);
}private static String bufferToHex(bytebytes[]) {return bufferToHex(bytes, 0, bytes.length);
}/*** 字符串的md5加密
*@paraminput
*@return
*/
public staticString stringMD5(String input) {//输入的字符串转换成字节数组
byte[] inputByteArray =input.getBytes();//inputByteArray是输入字符串转换得到的字节数组
messageDigest.update(inputByteArray);//转换并返回结果，也是字节数组，包含16个元素
byte[] resultByteArray =messageDigest.digest();//字符数组转换成字符串返回
returnbufferToHex(resultByteArray);
}/*** 文件的md5加密
*@paraminputFile
*@return*@throwsIOException*/
public static String fileMD5(String inputFile) throwsIOException {//缓冲区大小(这个可以抽出一个参数)
int bufferSize = 256 * 1024;
FileInputStream fileInputStream= null;
DigestInputStream digestInputStream= null;try{//使用DigestInputStream
fileInputStream = newFileInputStream(inputFile);
digestInputStream= newDigestInputStream(fileInputStream,messageDigest);//read的过程中进行MD5处理，直到读完文件
byte[] buffer =new byte[bufferSize];while (digestInputStream.read(buffer) > 0);//获取最终的MessageDigest
messageDigest=digestInputStream.getMessageDigest();//拿到结果，也是字节数组，包含16个元素
byte[] resultByteArray =messageDigest.digest();//同样，把字节数组转换成字符串
returnbufferToHex(resultByteArray);
}finally{try{
digestInputStream.close();
}catch(Exception e) {
}try{
fileInputStream.close();
}catch(Exception e) {
}
}
}/***@paramargs*/
public static voidmain(String[] args) {//测试字符串MD5加密//123456: e10adc3949ba59abbe56e057f20f883e//eastcom: 6997c46956185a7c4d452646fc9c69e2
System.out.println(stringMD5("eastcom"));try{long startTime =System.currentTimeMillis();//测试文件MD5加密
String FilePath = "D:/ilink_ide.zip"; //4227e9fc4bd71ff34887d47867967b29
System.out.println(fileMD5(FilePath));long endTime =System.currentTimeMillis();
System.out.println((endTime- startTime)/1000);
}catch(IOException e) {
e.printStackTrace();
}
}/*** 参考文章：
*http://www.zhihu.com/question/23702510*http://blog.csdn.net/lf_software_studio/article/details/8025497*http://my.oschina.net/laigous/blog/106646*http://blog.csdn.net/wangqiuyun/article/details/22941433
*/}