微信公众号开发之微信扫一扫

最近开发一个食堂项目，项目中用到使用微信扫一扫实现项目中的扫一扫的功能。

1、添加点击扫一扫的触发事件的按钮

扫一扫

2、添加微信扫一扫的js引用

3、后台调用微信扫一扫的相关参数的获取(后面会说)

4、方法调用

$(function() {
	scanCode();
});

5、开启微信扫一扫

function scanCode() {
	wx.config({
		debug : false, // 开启调试模式,调用的所有api的返回值会在客户端alert出来，若要查看传入的参数，可以在pc端打开，参数信息会通过log打出，仅在pc端时才会打印。
		appId : $("#appId").val(), // 必填，公众号的唯一标识
		timestamp : $("#timestamp").val(), // 必填，生成签名的时间戳
		nonceStr : $("#nonceStr").val(), // 必填，生成签名的随机串
		signature : $("#signature").val(),// 必填，签名，见附录1
		jsApiList : [ 'scanQRCode' ]// 必填，需要使用的JS接口列表，所有JS接口列表见附录2
	});
}

6、调用微信扫一扫

$("#scanQRCode").click(function() {
	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 */
		/*   desc : 'scanQRCode desc', */
		success : function(res) {
			var url = res.resultStr;//扫码后获取结果
			location.href =  url;
		}
	});
});

后台数据的获取

url参数为：扫一扫获取的结果，一般为路径或者加密之后的结果

JSSDK获取

public static Map  getJsSdk(String url) {
	Map returnMap = new HashMap();
	try {
		String ticket = getJsapiTicket();
		if(StringUtils.isNotBlank(ticket) && StringUtils.isNotBlank(url)){
			returnMap = sign(ticket, url);
                        returnMap.put("appId", IConstants.wxgzAppID);//微信公众号appId
		}
	} catch (Exception e) {
	}
	return returnMap;
}

生成签名

public static Map sign(String jsapi_ticket, String url) {
	Map result = new HashMap();
	String nonce_str = create_nonce_str(); 
	String timestamp = create_timestamp();
	String string;
	String signature = "";
	// 注意这里参数名必须全部小写，且必须有序
	string = "jsapi_ticket=" + jsapi_ticket + "&noncestr=" + nonce_str + "×tamp=" + timestamp + "&url=" + url;
	try {
		MessageDigest crypt = MessageDigest.getInstance("SHA-1");
		crypt.reset();
		crypt.update(string.getBytes("UTF-8"));
		signature = byteToHex(crypt.digest());
	} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
	} catch (UnsupportedEncodingException e) {
		e.printStackTrace();
	}
	result.put("url", url);
	result.put("jsapi_ticket", jsapi_ticket);
	result.put("nonceStr", nonce_str);
	result.put("timestamp", timestamp);
	result.put("signature", signature);
	return result;
}

public static String byteToHex(final byte[] hash) {
	Formatter formatter = new Formatter();
	for (byte b : hash) {
		formatter.format("%02x", b);
	}
	String result = formatter.toString();
	formatter.close();
	return result;
}
public static String create_nonce_str() {
	return UUID.randomUUID().toString();
}
public static String create_timestamp() {
	return Long.toString(System.currentTimeMillis() / 1000);
}

临时票据的生成

注意：ticket有时间刷新限制
public static String getJsapiTicket() throws Exception {
	String ticken = null;
	try {
		String access_token = getToken();
		if(access_token != null && StringUtils.isNotBlank(access_token)){
		// 创建HttpClient实例
		HttpClient httpclient = new DefaultHttpClient();
		// 创建Get方法实例
HttpGet httpgets = new HttpGet("https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token=" + access_token + "&type=jsapi"); // 免费api
		HttpResponse response = httpclient.execute(httpgets);
		HttpEntity entity = response.getEntity();
		if (entity != null) {
			InputStream instreams = entity.getContent();
			String str = convertStreamToString(instreams);
			JSONObject jsOb = JSONObject.fromObject(str);
			httpgets.abort();
			ticken = Public.mapTo(jsOb.get("ticket"), "");
		}
	}	
    } catch (Exception e) {
	// TODO: handle exception
    }
return ticken;
}

public static String convertStreamToString(InputStream is) {
	BufferedReader reader = new BufferedReader(new InputStreamReader(is));
	StringBuilder sb = new StringBuilder();
	String line = null;
	try {
		while ((line = reader.readLine()) != null) {
			sb.append(line + "\n");
		}
	} catch (IOException e) {
		e.printStackTrace();
	} finally {
		try {
			is.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	return sb.toString();
}

token获取

public static String getToken() throws Exception {
	String access_token = null;
	// 创建HttpClient实例
	HttpClient httpclient = new DefaultHttpClient();
	// 创建Get方法实例需要微信公众号appId+secret
	HttpGet httpgets = new HttpGet("https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid="
				+ IConstants.wxgzAppID + "&secret=" + IConstants.wxgzAppSecret);
	HttpResponse response = httpclient.execute(httpgets);
	HttpEntity entity = response.getEntity();
	Map maData = new HashMap();
	if (entity != null) {
		InputStream instreams = entity.getContent();
		String str = convertStreamToString(instreams);
		JSONObject jsOb = JSONObject.fromObject(str);
		httpgets.abort();
		access_token = Public.mapTo(jsOb.get("access_token"), "") ;
	}
	return access_token;
}

项目中的扫一扫功能已经上线，如果有疑问，请留言！！！