微信公众号指定用户消息推送

一. 说明

以上方法针对微信公众号提供的测试号，若是正式号（通过认证的），可以调用以下接口替换相关步骤

https://open.weixin.qq.com/connect/qrconnect?appid=APPID&redirect_uri=REDIRECT_URI&response_type=code&
scope=SCOPE&state=STATE#wechat_redirect 

参考连接：https://developers.weixin.qq.com/doc/oplatform/Website_App/WeChat_Login/Wechat_Login.html

二. 工具类

验签工具类

public class WxTokenCheckUtil {
    // 与接口配置信息中的Token要一致
    private static String token = "guniao";
    /**
     * 验证签名
     * @param signature 微信计算出的前面
     * @param timestamp 时间戳
     * @param nonce 唯一标识
     * @return
     */
    public static boolean checkSignature(String signature, String timestamp, String nonce) {
        String[] arr = new String[] { token, timestamp, nonce };
        // 将token、timestamp、nonce三个参数进行字典序排序
        Arrays.sort(arr);
        StringBuilder content = new StringBuilder();
        for (int i = 0; i < arr.length; i++) {
            content.append(arr[i]);
        }
        MessageDigest md = null;
        String tmpStr = null;

        try {
            md = MessageDigest.getInstance("SHA-1");
            byte[] digest = md.digest(content.toString().getBytes());
            //这是你计算出来的签名
            tmpStr = byteToStr(digest);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        //对比一下你计算出来的签名和微信的是否一致
        return tmpStr != null ? tmpStr.equals(signature.toUpperCase()) : false;
    }

    /**
     * 将字节数组转换为十六进制字符串
     *
     * @param byteArray
     * @return
     */
    private static String byteToStr(byte[] byteArray) {
        String strDigest = "";
        for (int i = 0; i < byteArray.length; i++) {
            strDigest += byteToHexStr(byteArray[i]);
        }
        return strDigest;
    }

    /**
     * 将字节转换为十六进制字符串
     *
     * @param mByte
     * @return
     */
    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;
    }
}

发送请求工具类

public class AuthUtil {
	public static JSONObject doGetJson(String url) throws ClientProtocolException, IOException {
		JSONObject jsonObject = null;
		DefaultHttpClient client = new DefaultHttpClient();
		HttpGet httpGet = new HttpGet(url);
		HttpResponse response = client.execute(httpGet);
		HttpEntity entity = response.getEntity();
		if (entity != null) {
			String result = EntityUtils.toString(entity, "UTF-8");
			jsonObject = JSONObject.fromObject(result);
		}
		httpGet.releaseConnection();
		return jsonObject;
	}

	public static JSONObject doPostJson(String url, String outStr) throws ClientProtocolException, IOException {
		DefaultHttpClient client = new DefaultHttpClient();
		HttpPost httpost = new HttpPost(url);
		JSONObject jsonObject = null;
		httpost.setEntity(new StringEntity(outStr, "UTF-8"));
		HttpResponse response = client.execute(httpost);
		String result = EntityUtils.toString(response.getEntity(), "UTF-8");
		jsonObject = JSONObject.fromObject(result);
		return jsonObject;
	}
}

三. 思路

1. 微信验签：需要后端写一个接口，微信后台配置接口信息和域名

验签接口

@RestController
@RequestMapping("/wx")
@Slf4j
public class WxTest {

    /**
     * 一个普通的提供验签开放接口
     */
    @RequestMapping("/niptest/valid")
    @ResponseBody
    public void wxValidTest(HttpServletRequest request, HttpServletResponse response) {

        //你可以打个日志看看
        log.debug("微信进来了。。。。");
        // 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");


        PrintWriter out = null;
        try {
            out = response.getWriter();
            // 通过检验signature对请求进行校验，若校验成功则原样返回echostr，表示接入成功，否则接入失败
            if (WxTokenCheckUtil.checkSignature(signature, timestamp, nonce)) {
                out.print(echostr);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                out.close();
            }
        }

    }

}

2. 网页授权接口：用于获取用户授权后的code，引导用户打开此页面，然后在redirect_uri 页面的路径中可以拿到code

// redirect_uri = URLEncoder.encode(http://2yhb6t.natappfree.cc + '/front/wx/index.html')
https://open.weixin.qq.com/connect/oauth2/authorize?appid=appid&redirect_uri=redirect_uri&
response_type=code&scope=snsapi_userinfo#wechat_redirect

3. 获取用户的openId：openId是用户的微信凭证，在上面步骤的redirect_uri的重定向页面中调用一下接口

 /**
     * Tea微信授权成功的回调函数
     *
     * @param request
     * @param response
     * @throws IOException
     */

    @RequestMapping("/callBack")
    public void deGet(HttpServletRequest request, HttpServletResponse response)throws Exception {
        //获取回调地址中的code
        String code = request.getParameter("code");
        System.out.println("code:"+code);
        //拼接url
        String url = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=" + appid + "&secret="
                + secret + "&code=" + code + "&grant_type=authorization_code";
        JSONObject jsonObject = AuthUtil.doGetJson(url);
        //1.获取微信用户的openid
        String openid = jsonObject.getString("openid");
        System.out.println("openid:"+openid);
        // 业务处理：可以存到redis中，再跟每条数据关联

    }

4. 给指定用户发送消息：这里的access_token是第一步中拿到的，在需要发送消息的地方调用一下方法

	 public static String obtainAccessToken() throws IOException {
		 String tokenData = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid="+appid+"&secret="+secret;
		 // 返回的用户信息json字符串
		 JSONObject jsonObject = AuthUtil.doGetJson(tokenData);
		 return jsonObject.getString("access_token");
	 }

/**
	  * 给关注该公众好的用户发送信息
	  * @throws Exception
	  */
	 public void sendTemplateInfo(String openId) throws Exception{

		 //获取公众号accessToken
		 String accessToken = obtainAccessToken();
		 //消息推送接口
		 String path = "https://api.weixin.qq.com/cgi-bin/message/template/send?access_token=" + accessToken;

		 //封装参数
		 JSONObject jsonData = new JSONObject();

		 jsonData.put("touser", openId);
		 jsonData.put("template_id", "template_id");

		 JSONObject data = new JSONObject();

		 JSONObject first = new JSONObject();
		 first.put("value","测试购票支付详情！");
		 first.put("color","#173177");

		 JSONObject keyword1 = new JSONObject();
		 keyword1.put("value","2112323832748239");
		 keyword1.put("color","#173177");

		 JSONObject keyword2 = new JSONObject();
		 keyword2.put("value","2022-12-22 00:00:00");
		 keyword2.put("color","#173177");

		 JSONObject keyword3 = new JSONObject();
		 keyword3.put("value","199.56元");
		 keyword3.put("color","#173177");

		 JSONObject keyword4 = new JSONObject();
		 keyword4.put("value","微信支付");
		 keyword4.put("color","#173177");

		 JSONObject remark = new JSONObject();
		 remark.put("value","温馨提示：请不要爽约哦！");
		 remark.put("color","#173177");

		 data.put("first",first);
		 data.put("keyword1",keyword1);
		 data.put("keyword2",keyword2);
		 data.put("keyword3",keyword3);
		 data.put("keyword4",keyword4);
		 data.put("remark",remark);
		 jsonData.put("data",data);

		 JSONObject jsonObject = AuthUtil.doPostJson(path, jsonData.toString());
	 }