java实现基于PKCS5Padding填充方式的AES加解密

加解密第三弹，java实现基于PKCS5Padding填充方式的AES加解密。本着互联网的分享精神，特意奉上代码。不多说，看代码，哥注释很详细，话说这算是哥的优点吗。。

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;


public class AESUtil {
	
	/**
	 * 密钥算法
	 */
	private static final String KEY_ALGORITHM = "AES";
	
	/**
	 * 加密/解密算法 / 工作模式 / 填充方式
	 * Java 6支持PKCS5Padding填充方式
	 * Bouncy Castle支持PKCS7Padding填充方式
	 */
	private static final String CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";
	
	/**
	 * 生成密钥
	 * @return	密钥
	 * @throws Exception
	 */
	public static String generateKey() throws Exception {
		//实例化密钥生成器
		KeyGenerator kg = KeyGenerator.getInstance(KEY_ALGORITHM);
		/**
		 * 设置AES密钥长度
		 * AES要求密钥长度为128位或192位或256位，java默认限制AES密钥长度最多128位
		 * 如需192位或256位，则需要到oracle官网找到对应版本的jdk下载页，在"Additional Resources"中找到
		 * "Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files",点击[DOWNLOAD]下载
		 * 将下载后的local_policy.jar和US_export_policy.jar放到jdk安装目录下的jre/lib/security/目录下，替换该目录下的同名文件
		 */
		kg.init(128);
		//生成密钥
		SecretKey secretKey = kg.generateKey();
		//获得密钥的字符串形式
		return Base64.encodeBase64String(secretKey.getEncoded());
	}
	
	/**
	 * AES加密
	 * @param source	源字符串
	 * @param key	密钥
	 * @return	加密后的密文
	 * @throws Exception
	 */
	public static String encrypt(String source, String key) throws Exception {
		byte[] sourceBytes = source.getBytes("UTF-8");
        byte[] keyBytes = Base64.decodeBase64(key);
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);  
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keyBytes, KEY_ALGORITHM));  
        byte[] decrypted = cipher.doFinal(sourceBytes);
        return Base64.encodeBase64String(decrypted);
	}
	
	/**
	 * AES解密
	 * @param encryptStr	加密后的密文
	 * @param key	密钥
	 * @return	源字符串
	 * @throws Exception
	 */
	public static String decrypt(String encryptStr, String key) throws Exception {
		byte[] sourceBytes = Base64.decodeBase64(encryptStr);
    	byte[] keyBytes = Base64.decodeBase64(key);
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);  
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(keyBytes, KEY_ALGORITHM));  
        byte[] decoded = cipher.doFinal(sourceBytes);  
        return new String(decoded, "UTF-8");
	}
	
}