java实现AES加密

加密
代码有详细解释，不多废话。
/**  
* 加密  
*   
* @param content 需要加密的内容  
* @param password  加密密码  
* @return  
*/   
public   static   byte [] encrypt(String content, String password) {  
        try  {             
                KeyGenerator kgen = KeyGenerator.getInstance("AES" );  
                kgen.init(128 ,  new  SecureRandom(password.getBytes()));  
                SecretKey secretKey = kgen.generateKey();  
                byte [] enCodeFormat = secretKey.getEncoded();  
                SecretKeySpec key = new  SecretKeySpec(enCodeFormat,  "AES" );  
                Cipher cipher = Cipher.getInstance("AES" ); // 创建密码器   
                byte [] byteContent = content.getBytes( "utf-8" );  
                cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化   
                byte [] result = cipher.doFinal(byteContent);  
                return  result;  // 加密   
        } catch  (NoSuchAlgorithmException e) {  
                e.printStackTrace();  
        } catch  (NoSuchPaddingException e) {  
                e.printStackTrace();  
        } catch  (InvalidKeyException e) {  
                e.printStackTrace();  
        } catch  (UnsupportedEncodingException e) {  
                e.printStackTrace();  
        } catch  (IllegalBlockSizeException e) {  
                e.printStackTrace();  
        } catch  (BadPaddingException e) {  
                e.printStackTrace();  
        }  
        return   null ;  
}

Java代码
/** 
* 加密 
*  
* @param content 需要加密的内容 
* @param password  加密密码 
* @return 
*/ 
public static byte[] encrypt(String content, String password) {  
        try {             
                KeyGenerator kgen = KeyGenerator.getInstance("AES");  
                kgen.init(128, new SecureRandom(password.getBytes()));  
                SecretKey secretKey = kgen.generateKey();  
                byte[] enCodeFormat = secretKey.getEncoded();  
                SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");  
                Cipher cipher = Cipher.getInstance("AES");// 创建密码器  
                byte[] byteContent = content.getBytes("utf-8");  
                cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化  
                byte[] result = cipher.doFinal(byteContent);  
                return result; // 加密  
        } catch (NoSuchAlgorithmException e) {  
                e.printStackTrace();  
        } catch (NoSuchPaddingException e) {  
                e.printStackTrace();  
        } catch (InvalidKeyException e) {  
                e.printStackTrace();  
        } catch (UnsupportedEncodingException e) {  
                e.printStackTrace();  
        } catch (IllegalBlockSizeException e) {  
                e.printStackTrace();  
        } catch (BadPaddingException e) {  
                e.printStackTrace();  
        }  
        return null;  
} 
        /**
         * 加密
         *
         * @param content 需要加密的内容
         * @param password  加密密码
         * @return
         */
        public static byte[] encrypt(String content, String password) {
                try {          
                        KeyGenerator kgen = KeyGenerator.getInstance("AES");
                        kgen.init(128, new SecureRandom(password.getBytes()));
                        SecretKey secretKey = kgen.generateKey();
                        byte[] enCodeFormat = secretKey.getEncoded();
                        SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
                        Cipher cipher = Cipher.getInstance("AES");// 创建密码器
                        byte[] byteContent = content.getBytes("utf-8");
                        cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
                        byte[] result = cipher.doFinal(byteContent);
                        return result; // 加密
                } catch (NoSuchAlgorithmException e) {
                        e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                        e.printStackTrace();
                } catch (InvalidKeyException e) {
                        e.printStackTrace();
                } catch (UnsupportedEncodingException e) {
                        e.printStackTrace();
                } catch (IllegalBlockSizeException e) {
                        e.printStackTrace();
                } catch (BadPaddingException e) {
                        e.printStackTrace();
                }
                return null;
        }
2.2 解密
代码有详细注释，不多废话
注意：解密的时候要传入byte数组
view plain copy to clipboard print ?
/**解密  
* @param content  待解密内容  
* @param password 解密密钥  
* @return  
*/   
public   static   byte [] decrypt( byte [] content, String password) {  
        try  {  
                 KeyGenerator kgen = KeyGenerator.getInstance("AES" );  
                 kgen.init(128 ,  new  SecureRandom(password.getBytes()));  
                 SecretKey secretKey = kgen.generateKey();  
                 byte [] enCodeFormat = secretKey.getEncoded();  
                 SecretKeySpec key = new  SecretKeySpec(enCodeFormat,  "AES" );              
                 Cipher cipher = Cipher.getInstance("AES" ); // 创建密码器   
                cipher.init(Cipher.DECRYPT_MODE, key);// 初始化   
                byte [] result = cipher.doFinal(content);  
                return  result;  // 加密   
        } catch  (NoSuchAlgorithmException e) {  
                e.printStackTrace();  
        } catch  (NoSuchPaddingException e) {  
                e.printStackTrace();  
        } catch  (InvalidKeyException e) {  
                e.printStackTrace();  
        } catch  (IllegalBlockSizeException e) {  
                e.printStackTrace();  
        } catch  (BadPaddingException e) {  
                e.printStackTrace();  
        }  
        return   null ;  
}  
Java代码
/**解密 
* @param content  待解密内容 
* @param password 解密密钥 
* @return 
*/ 
public static byte[] decrypt(byte[] content, String password) {  
        try {  
                 KeyGenerator kgen = KeyGenerator.getInstance("AES");  
                 kgen.init(128, new SecureRandom(password.getBytes()));  
                 SecretKey secretKey = kgen.generateKey();  
                 byte[] enCodeFormat = secretKey.getEncoded();  
                 SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");              
                 Cipher cipher = Cipher.getInstance("AES");// 创建密码器  
                cipher.init(Cipher.DECRYPT_MODE, key);// 初始化  
                byte[] result = cipher.doFinal(content);  
                return result; // 加密  
        } catch (NoSuchAlgorithmException e) {  
                e.printStackTrace();  
        } catch (NoSuchPaddingException e) {  
                e.printStackTrace();  
        } catch (InvalidKeyException e) {  
                e.printStackTrace();  
        } catch (IllegalBlockSizeException e) {  
                e.printStackTrace();  
        } catch (BadPaddingException e) {  
                e.printStackTrace();  
        }  
        return null;  
} 
        /**解密
         * @param content  待解密内容
         * @param password 解密密钥
         * @return
         */
        public static byte[] decrypt(byte[] content, String password) {
                try {
                         KeyGenerator kgen = KeyGenerator.getInstance("AES");
                         kgen.init(128, new SecureRandom(password.getBytes()));
                         SecretKey secretKey = kgen.generateKey();
                         byte[] enCodeFormat = secretKey.getEncoded();
                         SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");           
                         Cipher cipher = Cipher.getInstance("AES");// 创建密码器
                        cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
                        byte[] result = cipher.doFinal(content);
                        return result; // 加密
                } catch (NoSuchAlgorithmException e) {
                        e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                        e.printStackTrace();
                } catch (InvalidKeyException e) {
                        e.printStackTrace();
                } catch (IllegalBlockSizeException e) {
                        e.printStackTrace();
                } catch (BadPaddingException e) {
                        e.printStackTrace();
                }
                return null;
        }
2.3 测试代码
view plain copy to clipboard print ?
String content =  "test" ;  
String password = "12345678" ;  
//加密   
System.out.println("加密前："  + content);  
byte [] encryptResult = encrypt(content, password);  
//解密   
byte [] decryptResult = decrypt(encryptResult,password);  
System.out.println("解密后："  +  new  String(decryptResult));  
Java代码
String content = "test";  
String password = "12345678";  
//加密  
System.out.println("加密前：" + content);  
byte[] encryptResult = encrypt(content, password);  
//解密  
byte[] decryptResult = decrypt(encryptResult,password);  
System.out.println("解密后：" + new String(decryptResult)); 
                String content = "test";
                String password = "12345678";
                //加密
                System.out.println("加密前：" + content);
                byte[] encryptResult = encrypt(content, password);
                //解密
                byte[] decryptResult = decrypt(encryptResult,password);
                System.out.println("解密后：" + new String(decryptResult));
输出结果如下：
加密前：test
解密后：test
2.4 容易出错的地方
但是如果我们将测试代码修改一下，如下：
view plain copy to clipboard print ?
String content =  "test" ;  
String password = "12345678" ;  
//加密   
System.out.println("加密前："  + content);  
byte [] encryptResult = encrypt(content, password);  
try  {  
        String encryptResultStr = new  String(encryptResult, "utf-8" );  
        //解密   
        byte [] decryptResult = decrypt(encryptResultStr.getBytes( "utf-8" ),password);  
        System.out.println("解密后："  +  new  String(decryptResult));  
} catch  (UnsupportedEncodingException e) {  
        e.printStackTrace();  
}  
Javascript代码
String content = "test";  
String password = "12345678";  
//加密  
System.out.println("加密前：" + content);  
byte[] encryptResult = encrypt(content, password);  
try {  
        String encryptResultStr = new String(encryptResult,"utf-8");  
        //解密  
        byte[] decryptResult = decrypt(encryptResultStr.getBytes("utf-8"),password);  
        System.out.println("解密后：" + new String(decryptResult));  
} catch (UnsupportedEncodingException e) {  
        e.printStackTrace();  
} 
                String content = "test";
                String password = "12345678";
                //加密
                System.out.println("加密前：" + content);
                byte[] encryptResult = encrypt(content, password);
                try {
                        String encryptResultStr = new String(encryptResult,"utf-8");
                        //解密
                        byte[] decryptResult = decrypt(encryptResultStr.getBytes("utf-8"),password);
                        System.out.println("解密后：" + new String(decryptResult));
                } catch (UnsupportedEncodingException e) {
                        e.printStackTrace();
                }
则，系统会报出如下异常：
javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher
        at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
        at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
        at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
        at javax.crypto.Cipher.doFinal(DashoA13*..)
这主要是因为加密后的byte数组是不能强制转换成字符串的，换言之：字符串和byte数组在这种情况下不是互逆的；要避免这种情况，我们需要做一些修订，可以考虑将二进制数据转换成十六进制表示，主要有如下两个方法：
2.4.1将二进制转换成16进制
view plain copy to clipboard print ?
/**将二进制转换成16进制  
* @param buf  
* @return  
*/   
public   static  String parseByte2HexStr( byte  buf[]) {  
        StringBuffer sb = new  StringBuffer();  
        for  ( int  i =  0 ; i < buf.length; i++) {  
                String hex = Integer.toHexString(buf[i] & 0xFF );  
                if  (hex.length() ==  1 ) {  
                        hex = '0'  + hex;  
                }  
                sb.append(hex.toUpperCase());  
        }  
        return  sb.toString();  
}  
Java代码
/**将二进制转换成16进制 
* @param buf 
* @return 
*/ 
public static String parseByte2HexStr(byte buf[]) {  
        StringBuffer sb = new StringBuffer();  
        for (int i = 0; i < buf.length; i++) {  
                String hex = Integer.toHexString(buf[i] & 0xFF);  
                if (hex.length() == 1) {  
                        hex = '0' + hex;  
                }  
                sb.append(hex.toUpperCase());  
        }  
        return sb.toString();  
} 
        /**将二进制转换成16进制
         * @param buf
         * @return
         */
        public static String parseByte2HexStr(byte buf[]) {
                StringBuffer sb = new StringBuffer();
                for (int i = 0; i < buf.length; i++) {
                        String hex = Integer.toHexString(buf[i] & 0xFF);
                        if (hex.length() == 1) {
                                hex = '0' + hex;
                        }
                        sb.append(hex.toUpperCase());
                }
                return sb.toString();
        }
2.4.2 将16进制转换为二进制
view plain copy to clipboard print ?
/**将16进制转换为二进制  
* @param hexStr  
* @return  
*/   
public   static   byte [] parseHexStr2Byte(String hexStr) {  
        if  (hexStr.length() <  1 )  
                return   null ;  
        byte [] result =  new   byte [hexStr.length()/ 2 ];  
        for  ( int  i =  0 ;i< hexStr.length()/ 2 ; i++) {  
                int  high = Integer.parseInt(hexStr.substring(i* 2 , i* 2 + 1 ),  16 );  
                int  low = Integer.parseInt(hexStr.substring(i* 2 + 1 , i* 2 + 2 ),  16 );  
                result[i] = (byte ) (high *  16  + low);  
        }  
        return  result;  
}  
Java代码
/**将16进制转换为二进制 
* @param hexStr 
* @return 
*/ 
public static byte[] parseHexStr2Byte(String hexStr) {  
        if (hexStr.length() < 1)  
                return null;  
        byte[] result = new byte[hexStr.length()/2];  
        for (int i = 0;i< hexStr.length()/2; i++) {  
                int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);  
                int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);  
                result[i] = (byte) (high * 16 + low);  
        }  
        return result;  
} 
        /**将16进制转换为二进制
         * @param hexStr
         * @return
         */
        public static byte[] parseHexStr2Byte(String hexStr) {
                if (hexStr.length() < 1)
                        return null;
                byte[] result = new byte[hexStr.length()/2];
                for (int i = 0;i< hexStr.length()/2; i++) {
                        int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
                        int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
                        result[i] = (byte) (high * 16 + low);
                }
                return result;
        }
然后，我们再修订以上测试代码，如下：
view plain copy to clipboard print ?
String content =  "test" ;  
String password = "12345678" ;  
//加密   
System.out.println("加密前："  + content);  
byte [] encryptResult = encrypt(content, password);  
String encryptResultStr = parseByte2HexStr(encryptResult);  
System.out.println("加密后："  + encryptResultStr);  
//解密   
byte [] decryptFrom = parseHexStr2Byte(encryptResultStr);  
byte [] decryptResult = decrypt(decryptFrom,password);  
System.out.println("解密后："  +  new  String(decryptResult));  
Java代码
String content = "test";  
String password = "12345678";  
//加密  
System.out.println("加密前：" + content);  
byte[] encryptResult = encrypt(content, password);  
String encryptResultStr = parseByte2HexStr(encryptResult);  
System.out.println("加密后：" + encryptResultStr);  
//解密  
byte[] decryptFrom = parseHexStr2Byte(encryptResultStr);  
byte[] decryptResult = decrypt(decryptFrom,password);  
System.out.println("解密后：" + new String(decryptResult)); 
                String content = "test";
                String password = "12345678";
                //加密
                System.out.println("加密前：" + content);
                byte[] encryptResult = encrypt(content, password);
                String encryptResultStr = parseByte2HexStr(encryptResult);
                System.out.println("加密后：" + encryptResultStr);
                //解密
                byte[] decryptFrom = parseHexStr2Byte(encryptResultStr);
                byte[] decryptResult = decrypt(decryptFrom,password);
                System.out.println("解密后：" + new String(decryptResult));
测试结果如下：
加密前：test
加密后：73C58BAFE578C59366D8C995CD0B9D6D
解密后：test

2.5 另外一种加密方式
还有一种加密方式，大家可以参考如下：
view plain copy to clipboard print ?
/**  
      * 加密  
      *  
      * @param content 需要加密的内容  
      * @param password  加密密码  
      * @return  
      */   
     public   static   byte [] encrypt2(String content, String password) {  
             try  {  
                     SecretKeySpec key = new  SecretKeySpec(password.getBytes(),  "AES" );  
                     Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding" );  
                     byte [] byteContent = content.getBytes( "utf-8" );  
                     cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化   
                     byte [] result = cipher.doFinal(byteContent);  
                     return  result;  // 加密   
             } catch  (NoSuchAlgorithmException e) {  
                     e.printStackTrace();  
             } catch  (NoSuchPaddingException e) {  
                     e.printStackTrace();  
             } catch  (InvalidKeyException e) {  
                     e.printStackTrace();  
             } catch  (UnsupportedEncodingException e) {  
                     e.printStackTrace();  
             } catch  (IllegalBlockSizeException e) {  
                     e.printStackTrace();  
             } catch  (BadPaddingException e) {  
                     e.printStackTrace();  
             }  
             return   null ;  
     }  
Java代码
/** 
      * 加密 
      * 
      * @param content 需要加密的内容 
      * @param password  加密密码 
      * @return 
      */ 
     public static byte[] encrypt2(String content, String password) {  
             try {  
                     SecretKeySpec key = new SecretKeySpec(password.getBytes(), "AES");  
                     Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");  
                     byte[] byteContent = content.getBytes("utf-8");  
                     cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化  
                     byte[] result = cipher.doFinal(byteContent);  
                     return result; // 加密  
             } catch (NoSuchAlgorithmException e) {  
                     e.printStackTrace();  
             } catch (NoSuchPaddingException e) {  
                     e.printStackTrace();  
             } catch (InvalidKeyException e) {  
                     e.printStackTrace();  
             } catch (UnsupportedEncodingException e) {  
                     e.printStackTrace();  
             } catch (IllegalBlockSizeException e) {  
                     e.printStackTrace();  
             } catch (BadPaddingException e) {  
                     e.printStackTrace();  
             }  
             return null;  
     } 
   /**
         * 加密
         *
         * @param content 需要加密的内容
         * @param password  加密密码
         * @return
         */
        public static byte[] encrypt2(String content, String password) {
                try {
                        SecretKeySpec key = new SecretKeySpec(password.getBytes(), "AES");
                        Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");
                        byte[] byteContent = content.getBytes("utf-8");
                        cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
                        byte[] result = cipher.doFinal(byteContent);
                        return result; // 加密
                } catch (NoSuchAlgorithmException e) {
                        e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                        e.printStackTrace();
                } catch (InvalidKeyException e) {
                        e.printStackTrace();
                } catch (UnsupportedEncodingException e) {
                        e.printStackTrace();
                } catch (IllegalBlockSizeException e) {
                        e.printStackTrace();
                } catch (BadPaddingException e) {
                        e.printStackTrace();
                }
                return null;
        }
这种加密方式有两种限制
密钥必须是16位的
待加密内容的长度必须是16的倍数，如果不是16的倍数，就会出如下异常：
javax.crypto.IllegalBlockSizeException: Input length not multiple of 16 bytes
        at com.sun.crypto.provider.SunJCE_f.a(DashoA13*..)
        at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
        at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
        at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
        at javax.crypto.Cipher.doFinal(DashoA13*..)
要解决如上异常，可以通过补全传入加密内容等方式进行避免。