关于java中MD5加密（可直接使用）

本文转自：http://www.cnblogs.com/solove/archive/2011/10/18/2216715.html

上部分是转载的关于字符串的加密，后半部分则比较全，包括字符串、文件、字节数组、等

package util;
import java.security.MessageDigest;
public class Encript {
//十六进制下数字到字符的映射数组
private final static String[] hexDigits = {"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"};
/**把inputString加密*/
public static String md5(String inputStr){
return encodeByMD5(inputStr);
}
/**
* 验证输入的密码是否正确
* @param password 真正的密码（加密后的真密码）
* @param inputString 输入的字符串
* @return 验证结果，boolean类型
*/
public static boolean authenticatePassword(String password,String inputString){
if(password.equals(encodeByMD5(inputString))){
return true;
}else{
return false;
}
}
/**对字符串进行MD5编码*/
private static String encodeByMD5(String originString){
if (originString!=null) {
try {
//创建具有指定算法名称的信息摘要
MessageDigest md5 = MessageDigest.getInstance("MD5");
//使用指定的字节数组对摘要进行最后更新，然后完成摘要计算
byte[] results = md5.digest(originString.getBytes());
//将得到的字节数组变成字符串返回
String result = byteArrayToHexString(results);
return result;
} catch (Exception e) {
e.printStackTrace();
}
}
return null;
}
/**
* 轮换字节数组为十六进制字符串
* @param b 字节数组
* @return 十六进制字符串
*/
private static String byteArrayToHexString(byte[] b){
StringBuffer resultSb = new StringBuffer();
for(int i=0;i<b.length;i++){
resultSb.append(byteToHexString(b[i]));
}
return resultSb.toString();
}
//将一个字节转化成十六进制形式的字符串
private static String byteToHexString(byte b){
int n = b;
if(n<0)
n=256+n;
int d1 = n/16;
int d2 = n%16;
return hexDigits[d1] + hexDigits[d2];
}
}
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package com.angsentech.ssm.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
* MD5加密处理工具类
* @author Administrator
*
*/

public class MD5Utils {
/**
* 默认的密码字符串组合，用来将字节转换成 16 进制表示的字符,apache校验下载的文件的正确性用的就是默认的这个组合
*/
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 nsaex) {
System.err.println(MD5Utils.class.getName()
+ "初始化失败，MessageDigest不支持MD5Util。");
nsaex.printStackTrace();
}
}

/**
* 生成字符串的md5校验值
*
* @param s
* @return
*/
public static String getMD5String(String s) {
return getMD5String(s.getBytes());
}

/**
* 判断字符串的md5校验码是否与一个已知的md5码相匹配
*
* @param password
* 要校验的字符串
* @param md5PwdStr
* 已知的md5校验码
* @return
*/
public static boolean isEqualsToMd5(String password, String md5PwdStr) {
String s = getMD5String(password);
return s.equals(md5PwdStr);
}

/**
* 生成文件的md5校验值
*
* @param file
* @return
* @throws IOException
*/
public static String getFileMD5String(File file) throws IOException {
InputStream fis;
fis = 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());
}

/**
* 生成字节数组的md5校验值
*
* @param s
* @return
*/
public static String getMD5String(byte[] bytes) {
messagedigest.update(bytes);
return bufferToHex(messagedigest.digest());
}

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];// 取字节中高 4 位的数字转换, >>>
// 为逻辑右移，将符号位一起右移,此处未发现两种符号有何不同
char c1 = hexDigits[bt & 0xf];// 取字节中低 4 位的数字转换
stringbuffer.append(c0);
stringbuffer.append(c1);
}

/**
* 将源字符串使用MD5加密为字节数组
* @param source
* @return
*/
public static byte[] encode2bytes(String source) {
byte[] result = null;
try {
MessageDigest md = MessageDigest.getInstance("MD5");
md.reset();
md.update(source.getBytes("UTF-8"));
result = md.digest();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}

return result;
}

/**
* 将源字符串使用MD5加密为32位16进制数
* @param source
* @return
*/
public static String encode2hex(String source) {
byte[] data = encode2bytes(source);
StringBuffer hexString = new StringBuffer();
for (int i = 0; i < data.length; i++) {
String hex = Integer.toHexString(0xff & data[i]);

if (hex.length() == 1) {
hexString.append('0');
}

hexString.append(hex);
}

return hexString.toString();
}

/**
* 验证字符串是否匹配
* @param unknown 待验证的字符串
* @param okHex 使用MD5加密过的16进制字符串
* @return 匹配返回true，不匹配返回false
*/
public static boolean validate(String unknown , String okHex) {
return okHex.equals(encode2hex(unknown));
}
}