@Qualifier is not applicable for constructor

问题场景：

笔者在springboot项目中使用java_websocket作为客户端，调用第三方ws服务。

最初只调用一个ws服务，以下代码可以正常工作：

   @Bean
    public URI ttsUri() throws URISyntaxException {
        return new URI("ws://1.1.1.1:8888/xxx");
    }

@Slf4j
@Component("ttsOfflineClient")
public class OfflineTTSWsClient extends WebSocketClient {

  @Autowired
    public OfflineTTSWsClient(URI serverUri) throws IOException {
        super(serverUri);
    }
......
}

后来又加一个ws服务:ws://2.2.2.2:7777/aaaa 尝试写以下代码报错

@Bean(name = "ttsUri")
public URI ttsUri() throws URISyntaxException {
    return new URI("ws://1.1.1.1:8888/xxx");

}

@Autowired
@Qualifier(value = "ttsUri") 
    public OfflineTTSWsClient(URI serverUri) throws IOException {
        super(serverUri);
    }

//报错：@Qualifier is not applicable for constructor

正确方法

@Autowired
public OfflineTTSWsClient(@Qualifier(value = "ttsUri") URI serverUri) throws IOException {
   super(serverUri);
}

或者（注意两段代码差别）

public OfflineTTSWsClient(@Qualifier(value = "ttsUri") URI serverUri) throws IOException {
  super(serverUri);
}

最终两个ws正常工作代码如下：

@Bean(name = "ttsUri")
public URI ttsUri() throws URISyntaxException {
    return new URI(""ws://1.1.1.1:8888/xxx");
}

@Bean(name = "asrUri")
public URI asrUri() throws URISyntaxException {
    return new URI("ws://2.2.2.2:7777/aaaa");
}

@Slf4j
@Component("ttsOfflineClient")
public class OfflineTTSWsClient extends WebSocketClient {

@Autowired
    public OfflineTTSWsClient(@Qualifier(value = "ttsUri") URI serverUri) throws IOException {
        super(serverUri);
    }
}

@Slf4j
@Component("asrOfflineClient")
public class OfflineASRWsClient extends WebSocketClient {


    public OfflineASRWsClient(@Qualifier(value = "asrUri") URI serverUri) 
   {
        super(serverUri);
    }
}

 参考来源：https://stackoverflow.com/questions/42350828/why-qualifier-not-allowed-above-constructor