【Java】AES加机解密工具类代码

 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;

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

 public final class AES {
 　　　//加密
     public static String encrypt(String content, String key) throws Exception {

         Cipher cipher = Cipher.getInstance("AES");
         cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(generateKey(key).getEncoded(), "AES"));
         byte[] b = cipher.doFinal(content.getBytes("UTF-8"));

         if (b == null || b.length == 0) {
             return "";
         }

         StringBuffer buf = new StringBuffer();
         for (int i = 0; i < b.length; i++) {

             String hex = Integer.toHexString(b[i] & 0xFF);

             if (hex.length() == 1) {
                 hex = '0' + hex;
             }
             buf.append(hex.toUpperCase());
         }
         return buf.toString();
     }
     //解密
     public static String decrypt(String content, String key) throws Exception {

         if (content == null || content.length() == 0) {
             return null;
         }

         byte[] b = new byte[content.length() / 2];
         for (int i = 0; i < content.length() / 2; i++) {
             int high = Integer.parseInt(content.substring(i * 2, i * 2 + 1), 16);
             int low = Integer.parseInt(content.substring(i * 2 + 1, i * 2 + 2), 16);
             b[i] = (byte) (high * 16 + low);
         }

         Cipher cipher = Cipher.getInstance("AES");
         cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(generateKey(key).getEncoded(), "AES"));

         return new String(cipher.doFinal(b));
     }

     private static SecretKey generateKey(String key) throws NoSuchAlgorithmException {

         SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
         KeyGenerator kg = KeyGenerator.getInstance("AES");

         secureRandom.setSeed(key.getBytes());
         kg.init(128, secureRandom);

         return kg.generateKey();
     }
 　　　//测试
     public static void main(String[] args) {

         try {
             String str = "AES测试";
             String secretKey = "秘钥";

             System.out.println("秘钥:" + secretKey);
             System.out.println("明文:" + str);

             String str0 = encrypt(str, secretKey);
             System.out.println("密文:" + str0);
             System.out.println("解密:" + decrypt(str0, secretKey));

         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 }