package com.design.base.utils;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectOutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * 类说明: 简单的MD5的加密获取
 *
 * @Author: Return
 * @Create: 2018-04-24 
 * 
 */

public final class MD5Helper {

    private MD5Helper(){}
    
    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 {
            messagedigest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
    }
    
    /**
     * MD5字符串
     *
     * @param s
     * @return
     */
    public static String MD5(String s) {
        try {
            byte[] btInput = s.getBytes();
            messagedigest.update(btInput);
            byte[] md = messagedigest.digest();
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str);
        } catch (Exception e) {
            return null;
        }
    }
    
    /**
     * MD5 文件
     *
     * @param file
     * @return
     * @throws IOException
     */
    public static String getFileMD5String(File file) throws IOException {
        
        InputStream fis;
        fis = new BufferedInputStream(new FileInputStream(file));
        byte[] buffer = new byte[1024];
        int numRead = 0;
        while ((numRead = fis.read(buffer)) > 0) {
            messagedigest.update(buffer, 0, numRead);
        }
        fis.close();
        return bufferToHex(messagedigest.digest());
    }
    
    /**
     * 对象HashCode
     *
     * @param object
     * @return
     * @throws IOException
     */
    public static String getHashCode(Object object) throws IOException {
        if (object == null){
            return "";
        }
        
        String ss = null;
        ObjectOutputStream s = null;
        ByteArrayOutputStream bo = new ByteArrayOutputStream();
        try {
            s = new ObjectOutputStream(bo);
            s.writeObject(object);
            s.flush();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (s != null) {
                s.close();
                s = null;
            }
        }
        ss = MD5(bo.toString());
        return ss;
    }
    
    private static String bufferToHex(byte bytes[]) {
        return bufferToHex(bytes, 0, bytes.length);
    }
    
    private static String bufferToHex(byte bytes[], int m, int n) {
        StringBuffer stringbuffer = new StringBuffer(2 * n);
        int k = m + n;
        for (int l = m; l < k; l++) {
            appendHexPair(bytes[l], stringbuffer);
        }
        return stringbuffer.toString();
    }
    
    private static void appendHexPair(byte bt, StringBuffer stringbuffer) {
        char c0 = hexDigits[(bt & 0xf0) >> 4];
        char c1 = hexDigits[bt & 0xf];
        stringbuffer.append(c0);
        stringbuffer.append(c1);
    }
    
}