JAVA-接收微信服务器接消息推送

前提： 推送前微信方会发请求要求指定格式返回，才可以进行下一步.

微信原文连接https://developers.weixin.qq.com/doc/oplatform/Mobile_App/WeChat_Login/message_push.html

一、相关工具类

加密/解密工具类

public class WXBizMsgCryptUtils {

    static Charset CHARSET = Charset.forName("utf-8");
    Base64 base64 = new Base64();
    byte[] aesKey;
    String token;
    String appId;

    /**
     * 构造函数
     *
     * @param token          公众平台上，开发者设置的token
     * @param encodingAesKey 公众平台上，开发者设置的EncodingAESKey
     * @param appId          公众平台appid
     * @throws AesException 执行失败，请查看该异常的错误码和具体的错误信息
     */
    public WXBizMsgCryptUtils(String token, String encodingAesKey, String appId) throws AesException {
        if (encodingAesKey.length() != 43) {
            throw new AesException(AesException.IllegalAesKey);
        }

        this.token = token;
        this.appId = appId;
        aesKey = Base64.decodeBase64(encodingAesKey + "=");
    }

    // 生成4个字节的网络字节序
    byte[] getNetworkBytesOrder(int sourceNumber) {
        byte[] orderBytes = new byte[4];
        orderBytes[3] = (byte) (sourceNumber & 0xFF);
        orderBytes[2] = (byte) (sourceNumber >> 8 & 0xFF);
        orderBytes[1] = (byte) (sourceNumber >> 16 & 0xFF);
        orderBytes[0] = (byte) (sourceNumber >> 24 & 0xFF);
        return orderBytes;
    }

    // 还原4个字节的网络字节序
    int recoverNetworkBytesOrder(byte[] orderBytes) {
        int sourceNumber = 0;
        for (int i = 0; i < 4; i++) {
            sourceNumber <<= 8;
            sourceNumber |= orderBytes[i] & 0xff;
        }
        return sourceNumber;
    }

    /**
     * 对密文进行解密.
     *
     * @param text 需要解密的密文
     * @return 解密得到的明文
     * @throws AesException aes解密失败
     */
    String decrypt(String text) throws AesException {
        byte[] original;
        try {
            // 设置解密模式为AES的CBC模式
            Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
            SecretKeySpec key_spec = new SecretKeySpec(aesKey, "AES");
            IvParameterSpec iv = new IvParameterSpec(Arrays.copyOfRange(aesKey, 0, 16));
            cipher.init(Cipher.DECRYPT_MODE, key_spec, iv);

            // 使用BASE64对密文进行解码
            byte[] encrypted = Base64.decodeBase64(text);

            // 解密
            original = cipher.doFinal(encrypted);
        } catch (Exception e) {
            e.printStackTrace();
            throw new AesException(AesException.DecryptAESError);
        }

        String xmlContent, from_appid;
        try {
            // 去除补位字符
            byte[] bytes = PKCS7Encoder.decode(original);

            // 分离16位随机字符串,网络字节序和AppId
            byte[] networkOrder = Arrays.copyOfRange(bytes, 16, 20);

            int xmlLength = recoverNetworkBytesOrder(networkOrder);

            xmlContent = new String(Arrays.copyOfRange(bytes, 20, 20 + xmlLength), CHARSET);
            from_appid = new String(Arrays.copyOfRange(bytes, 20 + xmlLength, bytes.length),
                    CHARSET);
        } catch (Exception e) {
            e.printStackTrace();
            throw new AesException(AesException.IllegalBuffer);
        }

        // appid不相同的情况
        if (!from_appid.equals(appId)) {
            throw new AesException(AesException.ValidateAppidError);
        }
        return xmlContent;

    }

    /**
     * 检验消息的真实性，并且获取解密后的明文.
     * <ol>
     * 	<li>利用收到的密文生成安全签名，进行签名验证</li>
     * 	<li>若验证通过，则提取xml中的加密消息</li>
     * 	<li>对消息进行解密</li>
     * </ol>
     *
     * @param msgSignature 签名串，对应URL参数的msg_signature
     * @param timeStamp    时间戳，对应URL参数的timestamp
     * @param nonce        随机串，对应URL参数的nonce
     * @param postData     密文，对应POST请求的数据
     * @return 解密后的原文
     * @throws AesException 执行失败，请查看该异常的错误码和具体的错误信息
     */
    public String decryptMsgjson(String msgSignature, String timeStamp, String nonce, String postData)
            throws AesException {

        // 验证安全签名
        String signature = SHA1.getSHA1(token, timeStamp, nonce, postData);

        if (!signature.equals(msgSignature)) {
            throw new AesException(AesException.ValidateSignatureError);
        }

        // 解密
        String result = decrypt(postData);
        return result;
    }

    public static JSONObject readStreamToJson(BufferedReader reader) throws IOException {
        StringBuffer buffer = new StringBuffer();
        String line = "";
        while((line = reader.readLine()) != null){
            buffer.append(line);
        }
        return JSONObject.parseObject(buffer.toString());
    }
}

SHA1签名计算

public class SHA1 {

    SHA1() {
    }

    public static String getSHA1(String token, String timestamp, String nonce, String encrypt) throws AesException {
        try {
            String[] array = new String[]{token, timestamp, nonce, encrypt};
            StringBuffer sb = new StringBuffer();
            Arrays.sort(array);
            for (int i = 0; i < 4; ++i) {
                sb.append(array[i]);
            }
            String str = sb.toString();
            MessageDigest md = MessageDigest.getInstance("SHA-1");
            md.update(str.getBytes());
            byte[] digest = md.digest();
            StringBuffer hexstr = new StringBuffer();
            String shaHex = "";
            for (int i = 0; i < digest.length; ++i) {
                shaHex = Integer.toHexString(digest[i] & 255);
                if (shaHex.length() < 2) {
                    hexstr.append(0);
                }
                hexstr.append(shaHex);
            }
            return hexstr.toString();
        } catch (Exception var12) {
            var12.printStackTrace();
            throw new AesException(-40003);
        }
    }
}

异常类

@SuppressWarnings("serial")
public class AesException extends Exception {

    public final static int OK = 0;
    public final static int ValidateSignatureError = -40001;
    public final static int ParseXmlError = -40002;
    public final static int ComputeSignatureError = -40003;
    public final static int IllegalAesKey = -40004;
    public final static int ValidateAppidError = -40005;
    public final static int EncryptAESError = -40006;
    public final static int DecryptAESError = -40007;
    public final static int IllegalBuffer = -40008;
    private int code;
    private static String getMessage(int code) {
        switch (code) {
            case ValidateSignatureError:
                return "签名验证错误";
            case ParseXmlError:
                return "xml解析失败";
            case ComputeSignatureError:
                return "sha加密生成签名失败";
            case IllegalAesKey:
                return "SymmetricKey非法";
            case ValidateAppidError:
                return "appid校验失败";
            case EncryptAESError:
                return "aes加密失败";
            case DecryptAESError:
                return "aes解密失败";
            case IllegalBuffer:
                return "解密后得到的buffer非法";
            default:
                return null; 
        }
    }
    public int getCode() {
        return code;
    }
    AesException(int code) {
        super(getMessage(code));
        this.code = code;
    }
}

PKCS类

public class PKCS7Encoder {

    static Charset CHARSET = Charset.forName("utf-8");
    static int BLOCK_SIZE = 32;

    PKCS7Encoder() {
    }
    static byte[] encode(int count) {
        int amountToPad = BLOCK_SIZE - count % BLOCK_SIZE;
        if (amountToPad == 0) {
            amountToPad = BLOCK_SIZE;
        }
        char padChr = chr(amountToPad);
        String tmp = new String();
        for (int index = 0; index < amountToPad; ++index) {
            tmp = tmp + padChr;
        }
        return tmp.getBytes(CHARSET);
    }

    static byte[] decode(byte[] decrypted) {
        int pad = decrypted[decrypted.length - 1];
        if (pad < 1 || pad > 32) {
            pad = 0;
        }
        return Arrays.copyOfRange(decrypted, 0, decrypted.length - pad);
    }

    static char chr(int a) {
        byte target = (byte) (a & 255);
        return (char) target;
    }
}

签名校验工具

public class CheckUtils {

    // 小程序消息推送自己配置的token
    private static String token = "xxxxxx";

    public static void output(HttpServletResponse response, String returnValue) {
        try {
            ServletOutputStream output = response.getOutputStream();
            output.write(returnValue.getBytes());
            output.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 验证签名
     *
     * @param signature
     * @param timestamp
     * @param nonce
     * @return
     */
    public static boolean checkSignature(String signature, String timestamp, String nonce) {
        // 将token、timestamp、nonce三个参数进行字典排序
        String[] arr = new String[]{token, timestamp, nonce};
        Arrays.sort(arr);
        // 将三个参数字符串拼接成一个字符串
        StringBuilder content = new StringBuilder();
        for (int i = 0; i < arr.length; i++) {
            content.append(arr[i]);
        }
        try {
            //获取加密工具
            MessageDigest md = MessageDigest.getInstance("SHA-1");
            // 对拼接好的字符串进行sha1加密
            byte[] digest = md.digest(content.toString().getBytes());
            String tmpStr = byteToStr(digest);
            //获得加密后的字符串与signature对比
            return tmpStr != null ? tmpStr.equals(signature.toUpperCase()) : false;
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return false;
    }

    private static String byteToStr(byte[] byteArray) {
        String strDigest = "";
        for (int i = 0; i < byteArray.length; i++) {
            strDigest += byteToHexStr(byteArray[i]);
        }
        return strDigest;
    }

    private static String byteToHexStr(byte mByte) {
        char[] Digit = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A',
                'B', 'C', 'D', 'E', 'F'};
        char[] tempArr = new char[2];
        tempArr[0] = Digit[(mByte >>> 4) & 0X0F];
        tempArr[1] = Digit[mByte & 0X0F];
        String s = new String(tempArr);
        return s;
    }
}

二、回调方法

  //微信端配置
private static String token = "xxxxx";
private static String encodingAesKey = "xxxxxx";

@RequestMapping("/wx/check")
    @ResponseBody
    public void wxPush(HttpServletRequest request,
                       HttpServletResponse response) {
        try {
            // 微信服务器POST消息时用的是UTF-8编码，在接收时也要用同样的编码，否则中文会乱码；
            request.setCharacterEncoding("UTF-8");
            response.setCharacterEncoding("UTF-8");
            boolean isGet = request.getMethod().toLowerCase().equals("get");
            if (isGet) {
                // 微信加密签名，signature结合了开发者填写的token参数和请求中的timestamp参数、nonce参数。
                String signature = request.getParameter("signature");
                // 时间戳
                String timestamp = request.getParameter("timestamp");
                // 随机数
                String nonce = request.getParameter("nonce");
                // 随机字符串
                String echostr = request.getParameter("echostr");
                System.out.println(signature + "**" + timestamp + "**" + nonce);
                PrintWriter out = null;
                out = response.getWriter();
                if (CheckUtils.checkSignature(signature, timestamp, nonce)) {
                    out.print(echostr);
                    out.flush();
                }
            } else {
                //先回复空字符串，然后执行自己的业务
                CheckUtils.output(response, "success");
                String appid = devConfigApi.getValueByKey(SNOWY_THIRD_WECHAT_CLIENT_ID_KEY);
                // 时间戳
                String timestamp = request.getParameter("timestamp");
                String msgSignature = request.getParameter("msg_signature");
                // 随机数
                String nonce = request.getParameter("nonce");
                //获取密文内容
                JSONObject jsonObject = WXBizMsgCryptUtils.readStreamToJson(request.getReader());
                String encrypt = jsonObject.getString("Encrypt");
                //解密
                WXBizMsgCryptUtils pc = new WXBizMsgCryptUtils(token, encodingAesKey, appid);
                String jmResult = pc.decryptMsgjson(msgSignature, timestamp, nonce, encrypt);
                System.out.println("图片回调-->" + jmResult);
                //处理自身业务
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }