Feign 的动态 URL
2024-11-21 06:42:25 # Technical # Notes #Feign

继承 Feign.Builder，重写 target 方法

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@Component
public class FeignBuilderHelper extends Feign.Builder {

    private final DynamicUrlHelper dynamicUrlHelper;

    @Autowired
    public FeignBuilderHelper(DynamicUrlHelper dynamicUrlHelper) {
        this.dynamicUrlHelper = dynamicUrlHelper;
    }

    @Override
    public <T> T target(Target<T> target) {
        return super.target(new Target.HardCodedTarget<T>(target.type(), target.name(), target.url()) {
            @Override
            public String url() {
                String url = dynamicUrlHelper.dynamicUrl(this.name());
                return StringUtils.isBlank(url) ? super.url() : url;
            }
        });
    }
}

从配置中心，获取动态的URL

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@Configuration
public class DynamicUrlHelper {

    private static final String BIG_DATA_SERVER_NAME = "BigDataServer";

    @Value("${big.data.virtual.host:}")
    private String bigDataServerUrl;

    public String dynamicUrl(String targetName) {
        if (Objects.equals(targetName, BIG_DATA_SERVER_NAME)) {
            return bigDataServerUrl;
        }
        return Strings.EMPTY;
    }
}

注意

可能会出现 BeanCreationException 异常：

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Unsatisfied dependency expressed through constructor parammeter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creeating bean with name '......': FactoryBean threw exception object creation; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'feign.Feign$Builder' available: expected single matching bean but found 2: feignBuilderHelper,feignHystrixBuilder

解决：

FeignBuilderHelper 添加 @Primary 注解

Thanks

Feign：实现动态URL

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