[移动开发]java调用微信getWXACodeUnlimit()获取小程序码

小程序官方文档链接：https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/qr-code/wxacode.getUnlimited.html

需要注意base64转换需要拼接：data:image/jpg;base64,

public String getWxCode(String accessToken) {
		String PROGRAM_CODE_URL=“https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=%s”；
        try {
            String url=String.format(PROGRAM_CODE_URL, accessToken);
        	RestTemplate rest = new RestTemplate();
        	Map<String,Object> param = new HashMap<>();
        	// 限制32位
            param.put("scene", “123456”));
            // 必须发布的页面，非必填
            param.put("page", "pages/index/index");
            param.put("width", 430);
            param.put("auto_color", false);
            Map<String,Object> line_color = new HashMap<>();
            line_color.put("r", 0);
            line_color.put("g", 0);
            line_color.put("b", 0);
            param.put("line_color", line_color);
            log.info("调用生成微信URL接口传参:" + param);
            MultiValueMap<String, String> headers = new LinkedMultiValueMap<>();
            HttpEntity requestEntity = new HttpEntity(param, headers);
            ResponseEntity<byte[]> entity = rest.exchange(url, HttpMethod.POST, requestEntity, byte[].class, new Object[0]);
            log.info("调用小程序生成微信永久小程序码URL接口返回结果:" + entity.getBody());
            byte[] result = entity.getBody();
            log.info(Base64.encodeBase64String(result));
            res=Base64.encodeBase64String(result);
            if(StringUtils.isNotBlank(res)) {
            	String encoded = "data:image/jpg;base64," + res.replaceAll("[\\s*\t\n\r]", "");
            	return encoded;
            }
            
        } catch (Exception e) {
            log.error("调用小程序生成二维码失败:{}", e);
            throw new BussnessException("调用小程序生成二维码失败");
        }
        return res;
    }