java 实现md5

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class MD5 {
public static void main(String[] args) {
try {
System.out.println(getMD5EncryptedPwd("kakakakakakakakkakaklalalalala"));
} catch (Exception e) {
}
}

/**
* 将指定byte数组转换成16进制字符串
* @param b
* @return
*/
private static String byteToHexStr(byte[] b) {
StringBuffer hexString = new StringBuffer();
for (int i = 0; i < b.length; i++) {
String hex = Integer.toHexString(b[i] & 0xFF);
if (hex.length() == 1) {
hex = '0' + hex;
}
hexString.append(hex.toUpperCase());
}
return hexString.toString();
}

/**
* 获得加密后的16进制形式字符串
* @param password
* @return
* @throws NoSuchAlgorithmException
* @throws UnsupportedEncodingException
*/
private static String getMD5EncryptedPwd(String password) throws NoSuchAlgorithmException,
UnsupportedEncodingException {
if (password == null || password.trim().length() == 0) {
return "";
}
//声明消息摘要对象
MessageDigest md = MessageDigest.getInstance("MD5");
//将口令的数据传给消息摘要对象
md.update(password.getBytes("UTF-8"));
//获得消息摘要的字节数组
byte[] digest = md.digest();
//将字节数组格式加密后的口令转化为16进制字符串格式的口令
return byteToHexStr(digest);
}
}