一、根据当前日期生成MD5加密密码

package com.test;

import java.security.MessageDigest;

import java.text.SimpleDateFormat;

import java.util.Date;

public class Md5Test {

public void toMD5(String plainText) {

try {

//生成实现指定摘要

原文链接：http://www.cnblogs.com/xudong-bupt/archive/2013/05/10/3070899.html

二、生成密码明文和加密后的密码

import sun.misc.BASE64Encoder;

import java.util.Random;

import java.security.MessageDigest;

public class PasswordCreator {

public static class GeneratedPassword {

private String clearText;

private String encrypted;

private GeneratedPassword(String clearText, String encrypted) {

this.clearText = clearText;

this.encrypted = encrypted;

}

public String getClearText() {

return clearText;

}

public String getEncrypted() {

return encrypted;

}

}

//the below number 13,58,74 you can change any number for you company.

public static GeneratedPassword generate(int length) {

Random rnd = new Random(System.currentTimeMillis());

int letterLength = length - 1;

byte[] buf = new byte[letterLength];

for (int i = 0; i < letterLength; ++i) {

int idx = Math.abs(rnd.nextInt()) % 13;

int offset = idx % 2 == 1 ? 58 : 74;

int ch = offset + idx;

buf[i] = (byte) ch;

}

String clearText = insertRandomNumber(buf);

String encrypted = encryptUnsaltedSha1(clearText);

return new GeneratedPassword(clearText, encrypted);

}

//the below number 9, you can change any number for you company.

private static String insertRandomNumber(byte[] buf) {

StringBuffer sb = new StringBuffer(new String(buf));

Random rnd = new Random(System.currentTimeMillis());

int number = Math.abs(rnd.nextInt()) % 9;

int offset = Math.abs(rnd.nextInt()) % (sb.length());

sb.insert(offset, number);

return sb.toString();

}

private static String encryptUnsaltedSha1(String password) {

try {

String alg = "SHA-1";

MessageDigest digest = MessageDigest.getInstance(alg);

digest.update(password.getBytes("UTF-8"));

return new BASE64Encoder().encode(digest.digest());

} catch (Exception e) {

throw new RuntimeException(e);

}

}

//Other service can invoke this util like below:

public static void main(String[] args) {

GeneratedPassword password=generate(6);

System.out.println(password.getClearText());

System.out.println(password.getEncrypted());

}

/*the output like below:

JNRR6A

Yvp+P0KeFaBjamzJ3wW8yDUafko=*/

}

原文链接：http://my.oschina.net/forrest420/blog/103787