轉載請標明出處：http://blog.csdn.net/zhaoyanjun6/article/details/120874209
本文出自【趙彥軍的博客】

文章目錄

• Hex
• MD5Util
• 其他實現方式
• • 方式一
  • okio 實現方式

Hex

首先定義 Hex 工具類, 來源于 apache 開源工具類 https://commons.apache.org/proper/commons-codec/download_codec.cgi

/*** @author : zhaoyanjun* @time : 2021/6/8* @desc : file md5值 https://commons.apache.org/proper/commons-codec/download_codec.cgi*/ public class Hex {/*** Used to build output as hex.*/private static final char[] DIGITS_LOWER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd','e', 'f'};/*** Used to build output as hex.*/private static final char[] DIGITS_UPPER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D','E', 'F'};public Hex() {// use default encoding}/*** Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.* The returned array will be double the length of the passed array, as it takes two characters to represent any* given byte.** @param data a byte[] to convert to hex characters* @return A char[] containing lower-case hexadecimal characters* true:32位小寫 718b6dd54c8d1d3ad19eb99cb12f13e2* false:32位大寫 718B6DD54C8D1D3AD19EB99CB12F13E2*/public static char[] encodeHex(final byte[] data) {return encodeHex(data, true);}/*** Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.* The returned array will be double the length of the passed array, as it takes two characters to represent any* given byte.** @param data a byte[] to convert to Hex characters* @param toLowerCase {@code true} converts to lowercase, {@code false} to uppercase* @return A char[] containing hexadecimal characters in the selected case* @since 1.4*/public static char[] encodeHex(final byte[] data, final boolean toLowerCase) {return encodeHex(data, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER);}/*** Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.* The returned array will be double the length of the passed array, as it takes two characters to represent any* given byte.** @param data a byte[] to convert to hex characters* @param toDigits the output alphabet (must contain at least 16 chars)* @return A char[] containing the appropriate characters from the alphabet For best results, this should be either* upper- or lower-case hex.* @since 1.4*/protected static char[] encodeHex(final byte[] data, final char[] toDigits) {final int l = data.length;final char[] out = new char[l << 1];encodeHex(data, 0, data.length, toDigits, out, 0);return out;}/*** Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.** @param data a byte[] to convert to hex characters* @param dataOffset the position in {@code data} to start encoding from* @param dataLen the number of bytes from {@code dataOffset} to encode* @param toDigits the output alphabet (must contain at least 16 chars)* @param out a char[] which will hold the resultant appropriate characters from the alphabet.* @param outOffset the position within {@code out} at which to start writing the encoded characters.*/private static void encodeHex(final byte[] data, final int dataOffset, final int dataLen, final char[] toDigits,final char[] out, final int outOffset) {// two characters form the hex value.for (int i = dataOffset, j = outOffset; i < dataOffset + dataLen; i++) {out[j++] = toDigits[(0xF0 & data[i]) >>> 4];out[j++] = toDigits[0x0F & data[i]];}} }

MD5Util

import java.io.File import java.io.FileInputStream import java.io.IOException import java.io.InputStream import java.security.MessageDigest import java.security.NoSuchAlgorithmException/*** @author : zhaoyanjun* @time : 2021/9/17* @desc :*/ object MD5Util {/***文件Md5*/@Throws(NoSuchAlgorithmException::class, IOException::class)fun md5(file: File): String {FileInputStream(file).use { input ->return md5(input)}}/*** 字符串字符串md5*/@Throws(NoSuchAlgorithmException::class, IOException::class)fun md5(message: String): String {message.byteInputStream().use { input ->return md5(input)}}/*** 字節數組md5*/@Throws(NoSuchAlgorithmException::class, IOException::class)fun md5(byteArray: ByteArray): String {byteArray.inputStream().use { input ->return md5(input)}}/*** InputStream md5* 可處理大文件*/@Throws(NoSuchAlgorithmException::class, IOException::class)private fun md5(input: InputStream): String {val messageDigest = MessageDigest.getInstance("MD5")val buffer = ByteArray(8192)var length: Intwhile (input.read(buffer).also { length = it } != -1) {messageDigest.update(buffer, 0, length)}return String(Hex.encodeHex(messageDigest.digest()))} }

使用

//字符串md5 val message = "今天是周三" val md5 = MD5Util.md5(message)//文件md5 val file = File("") val md5 = MD5Util.md5(file)//字節數組md5 val byteArray = message.toByteArray() val md5 = MD5Util.md5(byteArray)

其他實現方式

方式一

fun getFileMD5(file: File): String? {val bufferSize = 4 * 1024var fileInputStream: FileInputStream? = nullvar digestInputStream: DigestInputStream? = nulltry {var messageDigest = MessageDigest.getInstance("MD5")fileInputStream = FileInputStream(file)digestInputStream = DigestInputStream(fileInputStream, messageDigest)val buffer = ByteArray(bufferSize)while (digestInputStream.read(buffer) > 0) messageDigest =digestInputStream.messageDigestval bigInt = BigInteger(1, messageDigest.digest())return bigInt.toString(16).padStart(32, '0')} catch (e: Exception) {return null} finally {try {digestInputStream?.close()} catch (e: Exception) {}try {fileInputStream?.close()} catch (e: Exception) {}} }

okio 實現方式

http://blog.csdn.net/zhaoyanjun6/article/details/119997762

總結

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