java - 类需要一个类型为 'java.lang.String' 的 bean，但无法找到

Question

我尝试在 Spring 中使用邮件服务。我使用 Spring-Boot 版本 2.1.7.Release 和 amazon-sqs-java-messaging-lib 版本 1.0.8。

我的代码如下:

    @Service
@RequiredArgsConstructor
public class MailService {

private static final Logger logger = Logger.getLogger(MailService.class.getName());
private final AmazonSQS amazonSQS;

@Value("${aws.sqs.queue.mail}")
private final String sqsQueueMail;

public void sendMail(final SQSMailParams mailParams) {

    final String queueUrl = amazonSQS.getQueueUrl(sqsQueueMail).getQueueUrl();

    try {
        final String messageBody = SQSMailParams.createSQSMailParams(mailParams, mailParams.getTemplateKey(), mailParams.getProcessId()).toJson();
        final SendMessageRequest sendMessageRequest = new SendMessageRequest(queueUrl, messageBody);
        sendMessageRequest.setMessageGroupId("TOLL-BOX-MAIL");

        amazonSQS.sendMessage(sendMessageRequest);
        logger.info("TOLL-BOX mail added to mail queue");
    } catch (JsonProcessingException e) {
        logger.error("Mail cannot be added to the mail queue: " + String.join(",", mailParams.recipients) + "." + e);
    }

    }
}

但是我通过运行代码遇到以下失败。

2020-03-02 07:34:00.242 ERROR 10568 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Parameter 1 of constructor in de.svg.tollbox.service.MailService required a bean of type 'java.lang.String' that could not be found.


Action:

Consider defining a bean of type 'java.lang.String' in your configuration.

Disconnected from the target VM, address: '127.0.0.1:43565', transport: 'socket'

Process finished with exit code 1

有人可以告诉我我做错了什么吗，谢谢。

Answer 1

从 sqsQueueMail 中删除 final。

@Value("${aws.sqs.queue.mail}")
private String sqsQueueMail;

这应该可以解决您的问题。不知何故，使用@RequiredArgsConstructor，变量的@Value注释未解析，这使得应用程序寻找String类型的bean