微信公众号调起扫码功能

偶然接触到了公众号开发。说需要调起微信扫一扫。便查看了公众号开发文档

看完文档后，发现js是相对简单的。唯一的难点是在java后台编写的秘钥生成代码。

也就是说。首先需要获取access_token，然后在根据access_token生成签名并返回。

以下是代码

    
	private static String GAPPID = "XXXXXXXXX";
	private static String GSECRET = "XXXXXXXXXXXXXX";
	private static String GRANTTYPE2 = "client_credential";// 获取 access-token 的

  
	@RequestMapping("/api/wx/getWxJsKey")
	@ResponseBody
	public String getWxJsKey(HttpServletRequest request) {
		HttpSession session = request.getSession();
		Map<String, Object> map = new HashMap<>();
		map.put("code", "1");
		map.put("errorMsg", "请求成功");
		String access_token = null;
		String jsapi_ticket = null;
		String timestamp = Long.toString(System.currentTimeMillis() / 1000);
		String noncestr = UUID.randomUUID().toString();
		System.out.println("timestamp:" + timestamp);
		System.out.println("noncestr:" + noncestr);
		// 获取 access_token
		{
			Object val = session.getAttribute("wx_access_token");
			if (val == null) {
				String requestUrl = "https://api.weixin.qq.com/cgi-bin/token?grant_type="
						+ GRANTTYPE2 + "&appid=" + GAPPID + "&secret="
						+ GSECRET;
				JSONObject json = CommonUtil.httpsRequest(requestUrl, "GET",
						null);
				logger.info(json);
				access_token = json.getString("access_token");
				session.setAttribute("wx_access_token", access_token);
				session.setMaxInactiveInterval(7200);
			} else {
				access_token = val.toString();
			}
		}
		// 获取 ticket
		{
			Object val = session.getAttribute("jsapi_ticket");
			if (val == null) {
				String requestUrl = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token="
						+ access_token + "&type=jsapi";
				JSONObject json = CommonUtil.httpsRequest(requestUrl, "GET",
						null);
				jsapi_ticket = json.getString("ticket");
				session.setAttribute("jsapi_ticket", jsapi_ticket);
				session.setMaxInactiveInterval(7200);
			} else {
				jsapi_ticket = val.toString();
			}
			System.out.println("jsapi_ticket:" + jsapi_ticket);
		}
		// 签名
		String jsKey = new StringBuffer()//
				.append("jsapi_ticket=").append(jsapi_ticket)//
				.append("&noncestr=").append(noncestr)//
				.append("&timestamp=").append(timestamp).append("&url=")//
				.append("https://hktest.ricepon.com/member-web/preOrderMeal/html/pre_order_meal.html")//
				.toString();
		// 加密 生成签名
		jsKey = DigestUtils.shaHex(jsKey);
		// 返回值
		Map<String, Object> param = new HashMap<>();
		param.put("jsKey", jsKey);
		param.put("timestamp", timestamp);
		param.put("noncestr", noncestr);
		param.put("appId", GAPPID);
		map.put("data", param);
		return JSONObject.fromObject(map).toString();
	}

然后在js中用ajax请求接口，处理即可。

var jsKey, noncestr, timestamp, appId, ajaxHeader = {};

$(document).ready(function () {

	//组装头部信息
	ajaxHeader = {
		Accept: "application/json; charset=utf-8",
	}

	// 获取 秘钥
	$.ajax({
		url: "../api/wx/getWxJsKey",
		type: "POST",
		headers: ajaxHeader,
		success: function (res) {
			if (res.code == 1) {
				var data = res.data;
				jsKey = data.jsKey; // 签名
				noncestr = data.noncestr; // 随机字符串
				timestamp = data.timestamp; // 时间戳
				appId = data.appId; // 小程序apId
				wx.config({
					debug: false,
					appId: appId,
					timestamp: timestamp,
					nonceStr: noncestr,
					signature: jsKey,
					jsApiList: ['scanQRCode']
				})
			} else {
				layer.msg(res.errorMsg);
			}
		},
		error: function (res) {
			layer.msg('error');
			layer.msg(res);
		}
	})
});

wx.error(function (res) {
	layer.msg(res.errorMsg);
});

wx.ready(function () {
	wx.checkJsApi({
		jsApiList: ['scanQRCode'],
		success: function (res) {}
	});
});

//调起扫码
function openScanDialog() {
	wx.scanQRCode({
		needResult: 1, // 默认为0，扫描结果由微信处理，1则直接返回扫描结果，
		scanType: ["qrCode", "barCode"], // 可以指定扫二维码还是一维码，默认二者都有
		success: function (res) {
			//自行处理
		}
	});
}

就是这样！