package util;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.apache.tomcat.util.codec.binary.Base64;
/**
 *
 * @author Administrator
 *
 */
public class AES {
    // 加密
    public static String Encrypt(String sSrc, String sKey) throws Exception {
        if (sKey == null) {
            System.out.print("Key为空null");
            return null;
        }
        // 判断Key是否为16位
        if (sKey.length() != 16) {
            System.out.print("Key长度不是16位");
            return null;
        }
        byte[] raw = sKey.getBytes("utf-8");
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");//"算法/模式/补码方式"
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
        byte[] encrypted = cipher.doFinal(sSrc.getBytes("utf-8"));
        return new Base64().encodeToString(encrypted);//此处使用BASE64做转码功能,同时能起到2次加密的作用。
    }
    // 解密
    public static String Decrypt(String sSrc, String sKey) throws Exception {
        try {
            // 判断Key是否正确
            if (sKey == null) {
                System.out.print("Key为空null");
                return null;
            }
            // 判断Key是否为16位
            if (sKey.length() != 16) {
                System.out.print("Key长度不是16位");
                return null;
            }
            byte[] raw = sKey.getBytes("utf-8");
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, skeySpec);
            byte[] encrypted1 = new Base64().decode(sSrc);//先用base64解密
            try {
                byte[] original = cipher.doFinal(encrypted1);
                String originalString = new String(original,"utf-8");
                return originalString;
            } catch (Exception e) {
                System.out.println(e.toString());
                return null;
            }
        } catch (Exception ex) {
            System.out.println(ex.toString());
            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;  
    }  
    /**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;  
    }  
    /**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;  
    }  
    
    public static void main(String[] args) throws Exception {
        /*
         * 此处使用AES-128-ECB加密模式,key需要为16位。
         */
        String cKey = "1234567890123456";
        // 需要加密的字串
        String cSrc = "www.gowhere.so";
        System.out.println(cSrc);
        // 加密
        String enString = AES.Encrypt(cSrc, cKey);
        System.out.println("加密后的字串是:" + enString);
        // 解密
        String DeString = AES.Decrypt(enString, cKey);
        System.out.println("解密后的字串是:" + DeString);
        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)); 
    }
}
原文:http://www.cnblogs.com/miaosj/p/6935379.html