package com.boying.common.util;

import org.apache.tomcat.util.security.MD5Encoder;
import org.springframework.util.DigestUtils;
import sun.security.provider.MD5;

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * MD5加密工具类
 */
public class MD5Util {

	public static String getMD5String(String str) {
		try {
			// 生成一个MD5加密计算摘要
			MessageDigest md = MessageDigest.getInstance("MD5");
			// 计算md5函数
			md.update(str.getBytes());
			// digest()最后确定返回md5 hash值，返回值为8位字符串。因为md5 hash值是16位的hex值，实际上就是8位的字符
			// BigInteger函数则将8位的字符串转换成16位hex值，用字符串来表示；得到字符串形式的hash值
			//一个byte是八位二进制，也就是2位十六进制字符（2的8次方等于16的2次方）
			return new BigInteger(1, md.digest()).toString(16);
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

	public static String byteArrayToHexString(byte[] b) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++) {
			resultSb.append(byteToHexString(b[i]));
		}
		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n = 256 + n;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	/**
	 * 加密
	 * 
	 * @param origin
	 *            原始字符串
	 * @return 32位字符串
	 */
	public static String encode(String origin) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			resultString = byteArrayToHexString(md.digest(resultString
					.getBytes()));
		} catch (Exception ex) {
			System.out.println(ex);
		}
		return resultString;
	}

	/**
	 * 
	 * @param origin
	 * @param charsetname
	 * @return
	 */
	public static String encode(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname))
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes()));
			else
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes(charsetname)));
		} catch (Exception exception) {
		}
		return resultString;
	}

	/**
	 * 发短信加密使用
	 * 
	 * @param source
	 * @return
	 */
	public static String encrypt(String source) {
		if (source == null) {
			source = "";
		}
		String result = "";
		try {
			result = encrypt(source, "MD5");
		} catch (NoSuchAlgorithmException ex) {
			// this should never happen
			throw new RuntimeException(ex);
		}
		return result;
	}

	private static String encrypt(String source, String algorithm)
			throws NoSuchAlgorithmException {
		byte[] resByteArray = encrypt(source.getBytes(), algorithm);
		return toHexString(resByteArray);
	}

	private static byte[] encrypt(byte[] source, String algorithm)
			throws NoSuchAlgorithmException {
		MessageDigest md = MessageDigest.getInstance(algorithm);
		md.reset();
		md.update(source);
		return md.digest();
	}

	private static String toHexString(byte[] res) {
		StringBuffer sb = new StringBuffer(res.length << 1);
		for (int i = 0; i < res.length; i++) {
			String digit = Integer.toHexString(0xFF & res[i]);
			if (digit.length() == 1) {
				digit = '0' + digit;
			}
			sb.append(digit);
		}
		return sb.toString().toLowerCase();
	}

	public static void main(String[] args) {
		String s ="amt=1.00&notifyUrl=http://test/payNotify&payKey=3ed6f127559e4f2f80e5e1cb0231b76b&payerName=tom&payerNum=54c51b276a9a47329b295662122968e1&payerTypeCode=130000451000011&paySecret=492f497a17cc41d19a757ae9d5809238";
		System.out.println(encode(s));
		String s2="amt=1.00&notifyUrl=http://test/payNotify&payKey=3ed6f127559e4f2f80e5e1cb0231b76b&paySecret=492f497a17cc41d19a757ae9d5809238&payerName=峰峰&payerNum=3aa0f6499acb45f686b6442229d23b31&payerTypeCode=130000451000012";
		System.out.println(DigestUtils.md5DigestAsHex(s.toString().getBytes()));
	}
}