package com.mine.util;

import java.security.DigestException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class DecryptUtil {

	public static void main(String[] args) throws DigestException {
		System.out.println(decrypt("123456", "SHA-1", Boolean.FALSE));
		System.out.println(decrypt("123456", "SHA-256", Boolean.FALSE));
		System.out.println(decrypt("123456", "MD5", Boolean.FALSE));
	}

	/**
	 * 对一个字符串进行指定算法的加密后，得到其十六进制字符串
	 * 
	 * @param decrypt			需要加密的字符串
	 * @param decryptType		加密的算法类型，如 SHA-1，MD5
	 * @param upper				加密结果是否转换为大写
	 * @return					加密后的字符串
	 * @throws DigestException	出错
	 */
	public static String decrypt(String decrypt, String decryptType, Boolean upper) throws DigestException {
		try {
			// 指定算法
			MessageDigest digest = MessageDigest.getInstance(decryptType);
			digest.update(decrypt.getBytes());
			// 获取字节数组
			byte messageDigest[] = digest.digest();
			// Create Hex String
			StringBuffer hexString = new StringBuffer();
			// 字节数组转换为【十六进制】数
			for (int i = 0; i < messageDigest.length; i++) {
				String shaHex = Integer.toHexString(messageDigest[i] & 0xFF);
				if (shaHex.length() < 2) {
					hexString.append(0);
				}
				hexString.append(shaHex);
			}
			return upper ? hexString.toString().toUpperCase() : hexString.toString();

		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
			throw new DigestException("签名错误！");
		}
	}

}