微信小程序生成二维码方式

生而为人 谁不付出 谁不努力

最近在小程序生成海报的时候 需要生成一个二维码放在海报上，让用户直接分享

第一种方式：前端直接生成base64的一个二维码图片 

qrcode_img:function(){
    let that = this;
    wx.request({
      url: 'https://api.weixin.qq.com/cgi-bin/token',
      data: {
        grant_type: 'client_credential',
        appid: '你的小程序APPID', //不能缺少
        secret: '你的小程序秘钥' //不能缺少
      },
      success: function (res) {
        wx.request({
          url: 'https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=' + res.data.access_token,
          data: {
            "path": "pages/index/index", //默认跳转到主页:pages/index/index，可指定
            "width": 200,
            "scene": "type=0&evaId=" + that.data.id,
          },
          responseType: 'arraybuffer', // 这行很重要,转为二进制数组
          header: {
            'content-type': 'application/json;charset=utf-8'
          },
          method: 'POST',
          success(res) {
            //转为base64
            let bin64 = wx.arrayBufferToBase64(res.data);
            that.setData({ //base 64设置到页面上
              qrcode_image: "data:image/png;base64," + bin64
            });
          }
        })
      }
    })
  }

第二种方式：后台生成二维码图片 

 public static Map doWXPost(String urls, JSONObject jsonParam) {
		 String msg ="";
		 Map<String,Object> map = new HashMap<String,Object>();
		  try
	        {
	            URL url = new URL(urls);
	            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
	            httpURLConnection.setRequestMethod("POST");// 提交模式
	            // conn.setConnectTimeout(10000);//连接超时 单位毫秒
	            // conn.setReadTimeout(2000);//读取超时 单位毫秒
	            // 发送POST请求必须设置如下两行
	            httpURLConnection.setDoOutput(true);
	            httpURLConnection.setDoInput(true);
	            // 获取URLConnection对象对应的输出流
	            PrintWriter printWriter = new PrintWriter(httpURLConnection.getOutputStream());
	            printWriter.write(jsonParam.toString());
	            // flush输出流的缓冲
	            printWriter.flush();
	            //开始获取数据
	            String path =Globals.IMAGE_URL+"/wechat/qrcoe/"; //图片存放地址
	            File imgPath = new File(path);
	            if(!imgPath.exists()){
	            	imgPath.mkdirs();
				}
	    		String fileName = DateUtils.dateToString(new Date(), "yyyyMMddHHmmss")+".png"; //图片名称
	            BufferedInputStream bis = new BufferedInputStream(httpURLConnection.getInputStream());
	            OutputStream os = new FileOutputStream(new File(Globals.IMAGE_URL+"/wechat/qrcoe/"+fileName));
	            int len;
	            byte[] arr = new byte[1024];
	            while ((len = bis.read(arr)) != -1)
	            {
	                os.write(arr, 0, len);
	                os.flush();
	            }
	            os.close();
	            msg = Globals.IMAGE_HOST+"/wechat/qrcoe/"+fileName;
	            map.put("imageUrl",msg);
	        }
	        catch (Exception e){
	            e.printStackTrace();
	        }
		  return map;
	    }