MD5加密封装

/*
 * @(#)DigestUtil.java		       Project:com.sinaapp.msdxblog.androidkit
 * Date:2012-12-18
 *
 * Copyright (c) 2011 CFuture09, Institute of Software, 
 * Guangdong Ocean University, Zhanjiang, GuangDong, China.
 * All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.lurencun.cfuture09.commons.security;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * @author Geek_Soledad ([e-mail])
 */
public class DigestUtil {
	/**
	 * 获取一个字符串加密后的16进制值
	 * 
	 * @param algorithm
	 *            摘要算法
	 * @param message
	 *            进行加密的String对象
	 * 
	 * @return String 计算后的结果
	 */
	public static String doDigest(String algorithm, String message) {
		return doDigest(algorithm, message.getBytes());
	}

	/**
	 * 获取一个字符串加密后的16进制值
	 * 
	 * @param algorithm
	 *            摘要算法
	 * @param message
	 *            进行加密的byte数组
	 * 
	 * @return String 计算后的结果
	 */
	public static String doDigest(String algorithm, byte[] message) {
		MessageDigest md = null;
		try {
			md = MessageDigest.getInstance(algorithm);
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}

		byte[] result = md.digest(message);
		return StringUtil.bytesToHexString(result);
	}

	/**
	 * 获取一个字符串加密后的16进制值
	 * 
	 * @param algorithm
	 *            摘要算法名称
	 * @param message
	 *            进行加密的byte数组
	 * 
	 * @return String 计算后的结果
	 */
	public static String doDigest(String algorithm, char[] message) {
		return doDigest(algorithm, new String(message));
	}
}

/*
 * @(#)StringUtil.java		       Project:com.sinaapp.msdxblog.androidkit
 * Date:2012-12-18
 *
 * Copyright (c) 2011 CFuture09, Institute of Software, 
 * Guangdong Ocean University, Zhanjiang, GuangDong, China.
 * All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.lurencun.cfuture09.commons.security;

/**
 * @author Geek_Soledad ([e-mail])
 */
public class StringUtil {

	/**
	 * byte[]数组转换为16进制的字符串。
	 * 
	 * @param data
	 *            要转换的字节数组。
	 * @return 转换后的结果。
	 */
	public static final String bytesToHexString(byte[] data) {
		StringBuilder valueHex = new StringBuilder();
		for (int i = 0, tmp; i < data.length; i++) {
			tmp = data[i] & 0xff;
			if (tmp < 16) {
				valueHex.append(0);
			}
			valueHex.append(Integer.toHexString(tmp));
		}
		return valueHex.toString();
	}
	
	/**
	 * 16进制表示的字符串转换为字节数组。
	 * 
	 * @param hexString
	 *            16进制表示的字符串
	 * @return byte[] 字节数组
	 */
	public static byte[] hexStringToBytes(String hexString) {
		if (hexString == null || hexString.equals("")) {
			return null;
		}
		hexString = hexString.toUpperCase();
		char[] hexChars = hexString.toCharArray();
		int length = hexString.length();
		byte[] d = new byte[length >>> 1];
		for (int n = 0; n < length; n += 2) {
			String item = new String(hexChars, n, 2);
			// 两位一组，表示一个字节,把这样表示的16进制字符串，还原成一个进制字节
			d[n >>> 1] = (byte) Integer.parseInt(item, 16);
		}
		return d;
	}
}