Spring boot WebSocket 注入失败

原来的写法：
@Autowired
SendMsgMqService sendMsgMqService; // 使用时sendMsgMqService为null

调整后的写法:
private static SendMsgMqService sendMsgMqService;

@Autowired
public void setSendMsgMqService(SendMsgMqService smms) {
sendMsgMqService = smms;
}