java——MD5加密算法（含验证）

package date;

import java.security.MessageDigest;

public class Password {
/** 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" };

/**
*
* 对input加密生成新密码
*
* @param inputString
*            待加密的字符串
* @return
*/
public static String createPassword(String inputString) {
return encodeByMD5(inputString);
}

/**
*
* 验证输入密码是否正确
*
* @param password
*            加密后的密码
* @param inputString
*            输入的明文密码
* @return
*/
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
*
* @param originString
* @return
*/
private static String encodeByMD5(String originString) {
if (originString != null) {
try {
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] results = md.digest(originString.getBytes());
String resultString = byteArrayToHexString(results);
return resultString.toUpperCase();
} catch (Exception ex) {
ex.printStackTrace();
}
}
return null;
}

/**
*
* 转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();
}

/**
* 转换一个字节为十六进制
*
* @param b
*            单个字节
* @return
*/
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];
}

public static void main(String args[]){


String password=Password.createPassword("945896808");

System.out.println(password);

System.out.println("对945896808加密后是否匹配"+Password.authenticatePassword(password, "945896808"));

System.out.println("加密后是否匹配"+Password.authenticatePassword(password, "888888888"));
}

}