import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.Base64;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
/***
 * 
 * @author Vaquar khan
 * 
 *
 */
public class AES {

    private static SecretKeySpec secretKey;
    private static final String VK_secretKey = "VaquarKhan-secrate-key!!!!";
    private static byte[] key;

    /**
     * 
     * @param myKey
     */
    public static void setKey(String myKey) {
        MessageDigest sha = null;
        try {
            key = myKey.getBytes("UTF-8");
            sha = MessageDigest.getInstance("SHA-1");
            key = sha.digest(key);
            key = Arrays.copyOf(key, 16);
            secretKey = new SecretKeySpec(key, "AES");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
    }
/**
 * encrypt
 * @param strToEncrypt
 * @param secret
 * @return
 */
    public static String encrypt(String strToEncrypt, String secret) {
        try {
            setKey(secret);
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
            return Base64.getEncoder().encodeToString(cipher.doFinal(strToEncrypt.getBytes("UTF-8")));
        } catch (Exception e) {
            System.out.println("Error while encrypting: " + e.toString());
        }
        return null;
    }
/**
 * decrypt
 * @param strToDecrypt
 * @param secret
 * @return
 */
    public static String decrypt(String strToDecrypt, String secret) {
        try {
            setKey(secret);
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
            cipher.init(Cipher.DECRYPT_MODE, secretKey);
            return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));
        } catch (Exception e) {
            System.out.println("Error while decrypting: " + e.toString());
        }
        return null;
    }

    public static void main(String[] args) {
        final String secretKey = VK_secretKey;
        String password = "VKhan@12";
        //
        String encryptedString = AES.encrypt(password, secretKey);
        String decryptedString = AES.decrypt(encryptedString, secretKey);
        //
        System.out.println(password);
        System.out.println(encryptedString);
        System.out.println(decryptedString);
    }

}

这是一个迟来的回答，但是Joshua Bloch在java.util.prefs包下提交了他的Base64类(当他为Sun工作时，嗯，Oracle)。这个类从JDK 1.4开始就存在了。

E.g.

String currentString = "Hello World";
String base64String = java.util.prefs.Base64.byteArrayToBase64(currentString.getBytes("UTF-8"));

Java .util的Java 8实现。Base64不依赖于其他Java 8特定的类。

我不确定这是否适用于Java 6项目，但可以复制并粘贴Base64.java文件到Java 7项目中，并编译它，除了导入Java .util. arrays和Java .util. objects之外，无需任何修改。

注意，Base64.java文件是由GNU GPL2覆盖的

希望这对你有所帮助:

import com.sun.org.apache.xml.internal.security.utils.Base64;
String str="Hello World";
String base64_str=Base64.encode(str.getBytes("UTF-8"));

Or:

String str="Hello World";
String base64_str="";
try
   {base64_str=(String)Class.forName("java.util.prefs.Base64").getDeclaredMethod("byteArrayToBase64", new Class[]{byte[].class}).invoke(null, new Object[]{str.getBytes("UTF-8")});
   }
catch (Exception ee) {}

java.util.prefs。Base64适用于本地rt.jar，

但是它不在JRE类白名单中

GAE/J白名单中没有列出的可用类

真遗憾!

PS.在android中，这很容易，因为android.util。Base64从Android API Level 8开始就被包含了。

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.Base64;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
/***
 * 
 * @author Vaquar khan
 * 
 *
 */
public class AES {

    private static SecretKeySpec secretKey;
    private static final String VK_secretKey = "VaquarKhan-secrate-key!!!!";
    private static byte[] key;

    /**
     * 
     * @param myKey
     */
    public static void setKey(String myKey) {
        MessageDigest sha = null;
        try {
            key = myKey.getBytes("UTF-8");
            sha = MessageDigest.getInstance("SHA-1");
            key = sha.digest(key);
            key = Arrays.copyOf(key, 16);
            secretKey = new SecretKeySpec(key, "AES");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
    }
/**
 * encrypt
 * @param strToEncrypt
 * @param secret
 * @return
 */
    public static String encrypt(String strToEncrypt, String secret) {
        try {
            setKey(secret);
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
            return Base64.getEncoder().encodeToString(cipher.doFinal(strToEncrypt.getBytes("UTF-8")));
        } catch (Exception e) {
            System.out.println("Error while encrypting: " + e.toString());
        }
        return null;
    }
/**
 * decrypt
 * @param strToDecrypt
 * @param secret
 * @return
 */
    public static String decrypt(String strToDecrypt, String secret) {
        try {
            setKey(secret);
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
            cipher.init(Cipher.DECRYPT_MODE, secretKey);
            return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));
        } catch (Exception e) {
            System.out.println("Error while decrypting: " + e.toString());
        }
        return null;
    }

    public static void main(String[] args) {
        final String secretKey = VK_secretKey;
        String password = "VKhan@12";
        //
        String encryptedString = AES.encrypt(password, secretKey);
        String decryptedString = AES.decrypt(encryptedString, secretKey);
        //
        System.out.println(password);
        System.out.println(encryptedString);
        System.out.println(decryptedString);
    }

}

特别是在通用Codec:类Base64解码(byte[]数组)或编码(byte[]数组)