AESUtils

import java.io.UnsupportedEncodingException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;

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

public class AESUtils {

	private static KeyGenerator keyGen;
	private static Cipher cipher;
	private static final String algorithmStr = "AES/ECB/PKCS5Padding";
	private static String keyStr = "aaaaaa";

	static {
		try {
			//    keyGen
			keyGen = KeyGenerator.getInstance("AES");
			keyGen.init(128);
			//    cipher
			cipher = Cipher.getInstance(algorithmStr);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void main(String[] args) throws NoSuchAlgorithmException {
		String string = "{\"name\": \"test\"}";
		String string2 = "www";
		String encryptString = encrypt(string);
		System.out.println("    : " + string + "    : " + encryptString + "    : " + decrypt(encryptString));
		String encryptString2 = encrypt(string2);
		System.out.println("    : " + string2 + "    : " + encryptString2 + "    : " + decrypt(encryptString2));
	}

	/**
	 *     .
	 */
	public static String encrypt(String content) {
		byte[] encryptedBytes = null;
		Key key = new SecretKeySpec(keyStr.getBytes(), "AES");
		try {
			cipher.init(Cipher.ENCRYPT_MODE, key);
			encryptedBytes = cipher.doFinal(stringToBytes(content));
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		return bytesToString(Base64.getEncoder().encode(encryptedBytes));
	}

	/**
	 *     .
	 */
	public static String decrypt(String content) {
		byte[] originBytes = null;

		Key key = new SecretKeySpec(keyStr.getBytes(), "AES");
		try {
			cipher.init(Cipher.DECRYPT_MODE, key);
			originBytes = cipher.doFinal(Base64.getDecoder().decode(content));
		} catch (Exception e) {
			e.printStackTrace();
		}
		return bytesToString(originBytes);
	}

	/**
	 *      .
	 */
	private static byte[] stringToBytes(String str) {
		return str.getBytes();
	}

	/**
	 *          .
	 */
	private static String bytesToString(byte[] bytes) {
		String string = null;
		try {
			string = new String(bytes, "utf-8");
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		return string;
	}
}