java实现MD5加密

来源：互联网发布：qq for mac版什么意思编辑：程序博客网时间：2024/05/18 01:34

作者：sundroid

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package com.sundroid.utils.common;import java.security.MessageDigest;import java.io.*;public class MD5Tool {// 0的ASCII码private static final int ASCII_0 = 48;// 9的ASCII码private static final int ASCII_9 = 57;// A的ASCII码private static final int ASCII_A = 65;// F的ASCII码private static final int ASCII_F = 70;// a的ASCII码private static final int ASCII_a = 97;// f的ASCII码private static final int ASCII_f = 102;// 可表示16进制数字的字符private static final char hexChar[] = { '0', '1', '2', '3', '4', '5', '6','7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };private static final String HASH_MD5 = "MD5";// private static Log log = Log.getInstance( MD5Tool.class);/** * 获取字节数组MD5码 *  * @param bs * @return */public final static String encoding(byte[] bs) {String encodingStr = null;try {MessageDigest mdTemp = MessageDigest.getInstance(HASH_MD5);mdTemp.update(bs);return toHexString(mdTemp.digest());} catch (Exception e) {// log.error(e);e.printStackTrace();}return encodingStr;}/** * 获取字符串MD5码 *  * @param text * @return */public final static String encoding(String text) {if (text == null) {return null;}return encoding(text.getBytes());}public final static String encodeTwice(String text) {if (text == null) {return null;}String md5Once = encoding(text.getBytes());return encoding(md5Once.getBytes());}/** * 获取文件内容MD5码 *  * @param filePath * @return */public final static String encodingFile(String filePath) {InputStream fis = null;try {fis = new FileInputStream(filePath);return encoding(fis);} catch (Exception ee) {return null;} finally {if (fis != null) {try {fis.close();} catch (Exception ex) {}}}}/** * 获取输入流MD5码 *  * @param fis * @return * @throws Exception */public final static String encoding(InputStream fis) throws Exception {byte[] buffer = new byte[1024];MessageDigest md5 = MessageDigest.getInstance(HASH_MD5);int numRead = 0;while ((numRead = fis.read(buffer)) > 0) {md5.update(buffer, 0, numRead);}return toHexString(md5.digest());}/** * 转换为用16进制字符表示的MD5 *  * @param b * @return */public static String toHexString(byte[] b) {StringBuilder sb = new StringBuilder(b.length * 2);for (int i = 0; i < b.length; i++) {sb.append(hexChar[(b[i] & 0xf0) >>> 4]);sb.append(hexChar[b[i] & 0x0f]);}return sb.toString();}/** * 检验是否是合法的MD5串 *  * @param md5Str * @return */public static boolean validate(String md5Str) {if (md5Str == null || md5Str.length() != 32) {return false;}byte[] by = md5Str.getBytes();for (int i = 0; i < by.length; i++) {int asciiValue = (int) by[i];if (asciiValue < ASCII_0|| (asciiValue > ASCII_9 && asciiValue < ASCII_A)|| (asciiValue > ASCII_F && asciiValue < ASCII_a)|| asciiValue > ASCII_f) {return false;}}return true;}public static void main(String[] args) {System.out.println(encodeTwice("sundroid"));System.out.println(validate(encodeTwice("sundroid")));}}

我们在做开发时一些敏感信息需要加密的MD5是个不错的选择，比如写入在数据库用户的信息，账号密码等等，如果不进行加密那么是极不安全的

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