package com.shlanbao.tzsc.utils.tools;

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

/**
 * MD5加密工具类
 * <li>@author Leejean
 * <li>@create 2014-6-24 下午04:13:41
 *
 * @author zhuguifei
 * @update 2019-06-03
 * @desc 添加SHA256加密
 */
public class MD5Util {

    public static void main(String[] args) {
        String s = "lanbaoit";
        System.out.println(md5(s));
        System.out.println("SHA256:" + SHA256(s));
    }

    /**
     * md5加密
     *
     * @param str
     * @return
     */
    public static String md5(String str) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(str.getBytes());
            byte[] byteDigest = md.digest();
            int i;
            StringBuffer buf = new StringBuffer("");
            for (int offset = 0; offset < byteDigest.length; offset++) {
                i = byteDigest[offset];
                if (i < 0)
                    i += 256;
                if (i < 16)
                    buf.append("0");
                buf.append(Integer.toHexString(i));
            }
            // 32位加密
            //return buf.toString();
            // 16位的加密
            return buf.toString().substring(8, 24);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 传入文本内容，返回 SHA-256 串
     *
     * @param strText
     * @return
     */
    public static String SHA256(final String strText) {
        return SHA(strText, "MD5");
    }

    /**
     * 传入文本内容，返回 SHA-512 串
     *
     * @param strText
     * @return
     */
    public static String SHA512(final String strText) {
        return SHA(strText, "SHA-512");
    }

    /**
     * 字符串 SHA 加密
     *
     * @param
     * @return
     */
    private static String SHA(final String strText, final String strType) {
        // 返回值
        String strResult = null;

        // 是否是有效字符串
        if (strText != null && strText.length() > 0) {
            try {
                // SHA 加密开始
                // 创建加密对象 并傳入加密類型
                MessageDigest messageDigest = MessageDigest
                        .getInstance(strType);
                // 传入要加密的字符串
                messageDigest.update(strText.getBytes());

                byte byteBuffer[] = messageDigest.digest();

                StringBuffer strHexString = new StringBuffer();
                // 遍歷 byte buffer
                for (int i = 0; i < byteBuffer.length; i++) {
                    String hex = Integer.toHexString(0xff & byteBuffer[i]);
                    if (hex.length() == 1) {
                        strHexString.append('0');
                    }
                    strHexString.append(hex);
                }
                // 得到返回結果
                strResult = strHexString.toString();
            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            }
        }

        return strResult;
    }

}