利用weixin-java-miniapp生成小程序码并直接返回图片

// 获取小程序服务实例
WxMaService wxMaService = WxMaConfiguration.getWxMaService();

// 获取小程序二维码生成实例
WxMaQrcodeService wxMaQrcodeService = wxMaService.getQrcodeService();

// 设置小程序二维码线条颜色为黑色
WxMaCodeLineColor lineColor = new WxMaCodeLineColor("0", "0", "0");

// 生成二维码图片字节流（此处也可以生成File类型，如果想将图片文件保存到服务器就生成File类型，此处生成byte[]类型，方便直接返回文件流到前端）
byte[] qrCodeBytes = null;
qrCodeBytes = wxMaQrcodeService.createWxaCodeUnlimitBytes(String.valueOf(id), null, 430, false, lineColor, false);

@RestController
@RequestMapping("/qrCode")
public class QrCodeController {
 private static final Logger logger = LoggerFactory.getLogger(QrCodeController.class);

 @GetMapping("/getMiniappQrCode/{id}")
 public void getMiniappQrCode(@PathVariable("id") Long id, HttpServletRequest request, HttpServletResponse response) throws Exception{
  // 获取小程序服务实例
  WxMaService wxMaService = WxMaConfiguration.getWxMaService();
  // 获取小程序二维码生成实例
  WxMaQrcodeService wxMaQrcodeService = wxMaService.getQrcodeService();

  // 设置小程序二维码线条颜色为黑色
  WxMaCodeLineColor lineColor = new WxMaCodeLineColor("0", "0", "0");

  // 生成二维码图片字节流
  byte[] qrCodeBytes = null;
  try{
   qrCodeBytes = wxMaQrcodeService.createWxaCodeUnlimitBytes(String.valueOf(id), null, 430, false, lineColor, false);
  } catch(Exception e){
   logger.error("生成小程序码出错", e);
  }

  // 设置contentType
  response.setContentType("image/png");

  // 写入response的输出流中
  OutputStream stream = response.getOutputStream();
  stream.write(qrCodeBytes);
  stream.flush();
  stream.close();
 }
}