Open Feign
使用
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| <dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
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| import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
@FeignClient(name = "<service_name>", path = "<url>")
public interface FeignTest {
@GetMapping
String getVersion();
}
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在主类启用 OpenFeign
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| @SpringBootApplication
@EnableFeignClients
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
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配置请求方式
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| spring:
cloud:
openfeign:
client:
config:
default:
connectTimeout: 5000
readTimeout: 5000
loggerLevel: basic
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自定义异常类
在默认情况下 Feign 只会抛出 FeignException 异常，如有需求可以使用 ErrorDecoder 抛出异常。
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| public class StashErrorDecoder implements ErrorDecoder {
@Override
public Exception decode(String methodKey, Response response) {
if (response.status() >= 400 && response.status() <= 499) {
return new StashClientException(
response.status(),
response.reason()
);
}
if (response.status() >= 500 && response.status() <= 599) {
return new StashServerException(
response.status(),
response.reason()
);
}
return errorStatus(methodKey, response);
}
}
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| public class MyFeignClientConfiguration {
@Bean
public ErrorDecoder errorDecoder() {
return new StashErrorDecoder();
}
}
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fallback
Spring Cloud CircuitBreaker 支持回退的概念：当远程地址无法链接或出现错误时执行的默认代码。要为给定的 @FeignClient 启用 fallback，需要将该属性设置为实现回退的类名。
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| @FeignClient(name = "test", url = "http://localhost:${server.port}/", fallback = Fallback.class)
protected interface TestClient {
@RequestMapping(method = RequestMethod.GET, value = "/hello")
Hello getHello();
@RequestMapping(method = RequestMethod.GET, value = "/hellonotfound")
String getException();
}
@Component
static class Fallback implements TestClient {
@Override
public Hello getHello() {
throw new NoFallbackAvailableException("Boom!", new RuntimeException());
}
@Override
public String getException() {
return "Fixed response";
}
}
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并且配置如下参数：
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| spring:
cloud:
openfeign:
circuitbreaker:
enabled: true
alphanumeric-ids:
enabled: true
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参考资料
官方文档