Spring Boot-@Value在@Component类中返回null

如何解决Spring Boot-@Value在@Component类中返回null

这是一个简单的类，其中我试图用@value映射错误消息。

我没有在属性文件中添加相应的值，因为我已经设置了默认值

@Slf4j
@Component
public class RestTemplateResponseErrorHandler
        implements ResponseErrorHandler {

    @Value("${invalid.password:test}")
    private String invalidPassword;


    @Override
    public boolean hasError(ClientHttpResponse httpResponse)
            throws IOException {

        return (
                httpResponse.getStatusCode().series() == CLIENT_ERROR
                        || httpResponse.getStatusCode().series() == SERVER_ERROR);
    }

    @Override
    public void handleError(ClientHttpResponse httpResponse)
            throws IOException {

        if (httpResponse.getStatusCode()
                .series() == SERVER_ERROR) {
            log.info("RestTemplateResponseErrorHandler --- SERVER_ERROR");
            // handle SERVER_ERROR
        } else if (httpResponse.getStatusCode()
                .series() == CLIENT_ERROR) {
            log.info("RestTemplateResponseErrorHandler --- CLIENT_ERROR");

            if (httpResponse.getStatusCode() == HttpStatus.BAD_REQUEST)
                throw new UnAuthorisedRequestException(invalidPassword);


        }
    }
}

在这里抛出新的UnAuthorisedRequestException（invalidPassword）;返回null

不确定类是什么问题，因为它被标记为@Component

@Configuration
public class CommonBeanConfig {

    @Bean
    public RestTemplate restTemplate(SSLSocketFactory sslSocketFactory) {
        CloseableHttpClient httpClient = HttpClients.custom()
                .setSSLSocketFactory(new SSLConnectionSocketFactory(sslSocketFactory,new NoopHostnameVerifier()))
                .build();
        HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
        requestFactory.setHttpClient(httpClient);
        RestTemplate restTemplate = new RestTemplate(new BufferingClientHttpRequestFactory(requestFactory));
        restTemplate.setInterceptors(Collections.singletonList(new ClientLoggingInterceptor()));
        restTemplate.setErrorHandler(new RestTemplateResponseErrorHandler());
        return restTemplate;
    }

}

该类被添加为异常处理程序

解决方法

您的示例中的

String不是由spring管理的-您可以“手动”创建它。因此spring不能将RestTemplateResponseErrorHandler用于它无法管理的对象。

尝试以下操作：

@Value

注意，由于您已经在使用java config-不必放置@Component 在@Configuration public class CommonBeanConfig { @Bean public RestTemplateResponseErrorHandler restTemplateErrorHandler() { return new RestTemplateErrorHandler(); } @Bean public RestTemplate restTemplate(SSLSocketFactory sslSocketFactory) { CloseableHttpClient httpClient = HttpClients.custom() .setSSLSocketFactory(new SSLConnectionSocketFactory(sslSocketFactory,new NoopHostnameVerifier())) .build(); HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(); requestFactory.setHttpClient(httpClient); RestTemplate restTemplate = new RestTemplate(new BufferingClientHttpRequestFactory(requestFactory)); restTemplate.setInterceptors(Collections.singletonList(new ClientLoggingInterceptor())); restTemplate.setErrorHandler(restTemplateErrorHandler()); // or inject the parameter into the method public RestTemplate restTemplate(SSLSocketFactory sslSocketFactory,RestTemplateErrorHandler restTemplateErrorHandler) return restTemplate; } } 类上。

如果您确实必须使用RestTemplateErrorHandler并希望通过组件扫描来发现和实例化它-请勿在Java配置中为错误处理程序创建Bean并使用我在注释中提到的方法@Component：

restTemplate