java实现AES加密(解决中文解密后乱码问题，解决传输字符串后解密报错的问题)

在对安全性要求比较高的报文做加密的时候，算法有很多种，我这里主要用到的就是AES加密算法。由于在国内使用，所以不可避免的要对中文进行加密和解密，而在这个过程中，发现，如果不做处理，很容易会出现中文乱码。

下面是常见的情况：

一、中文乱码

不对密码进行编码处理

        byte[] decryptResult = decrypt(encryptResult, password);
        System.out.println("解密后：" + new String(decryptResult));

运行后

加密前：我是shoneworn
解密后：鎴戞槸shoneworn

二、对文字进行编码处理，但是在传输过程中草率的将byte[]转成String,  String code = new String(bytes); 由于AES加密算法要求密文是16位的倍数。所以，这么处理，在解密的时候，就会报各种错。比如下面的。

    String code = new String(encryptResult);
        byte[] decryptResult = decrypt(code.getBytes(), password);

结果就.........

加密前：我是shoneworn
javax.crypto.BadPaddingException: Given final block not properly padded
    at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:966)
    at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:824)
    at com.sun.crypto.provider.AESCipher.engineDoFinal(AESCipher.java:436)
    at javax.crypto.Cipher.doFinal(Cipher.java:2165)
    at com.ailin.test.AES.decrypt(AES.java:72)
    at com.ailin.test.AES.main(AES.java:173)
Exception in thread "main" java.lang.NullPointerException
    at java.lang.String.<init>(Unknown Source)
    at com.ailin.test.AES.main(AES.java:174)

三、给功能正常的，能传中文的，不报错的AES加密加密算法源码

package com.ailin.test;

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;

public class AES {
    /**
     * 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;
    }

    /**
     * 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;
    }

    public static void main(String[] args) throws UnsupportedEncodingException {
        String content = "我是shoneworn";
        String password = "12345678";
        // 加密
        System.out.println("加密前：" + content);
        byte[] encode = encrypt(content, password);
        
        //传输过程,不转成16进制的字符串，就等着程序崩溃掉吧
        String code = parseByte2HexStr(encode);
        System.out.println("密文字符串：" + code);
        byte[] decode = parseHexStr2Byte(code);
        // 解密
        byte[] decryptResult = decrypt(decode, password);
        System.out.println("解密后：" + new String(decryptResult, "UTF-8")); //不转码会乱码
         
    }
}