SpringCloud Feign

• Feign配置

#超时重试配置
HELLO-SERVICE.ribbon.ConnectTimeout=250
HELLO-SERVICE.ribbon.ReadTimeout=1000
HELLO-SERVICE.ribbon.OkToRetryOnAllOperations=true
HELLO-SERVICE.ribbon.MaxAutoRetriesNextServer=2
HELLO-SERVICE.ribbon.MaxAutoRetries=1
#压缩配置
#spring-configuration-metadata.json 在这个文件中查看默认的配置值
feign.compression.request.enabled=true
feign.compression.request.min-request-size=2048
feign.compression.request.mime-types=text/xml,application/xml,application/json

#是否开启feign中的hystrix熔断功能
feign.hystrix.enabled=false
#关闭熔断功能
hystrix.command.default.execution.timeout.enabled=true
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=1000
hystrix.command.hello.execution.isolation.thread.timeoutInMilliseconds=5000

注意和hystrix的timeoutInMilliseconds关系

• Feign的用法

1. 利用注解客户端

@FeignClient(name="HELLO-SERVICE", fallback = HelloServiceFallback.class)
public interface HelloService {

    @RequestMapping("/hello")
    String hello();

    @RequestMapping(value = "/hello1", method = RequestMethod.GET)
    String hello(@RequestParam("name") String name) ;

    @RequestMapping(value = "/hello2", method = RequestMethod.GET)
    User hello(@RequestHeader("name") String name, @RequestHeader("age") Integer age);

    @RequestMapping(value = "/hello3", method = RequestMethod.POST)
    String hello(@RequestBody User user);

}

其中HelloServiceFallback为服务降级类

@Component
public class HelloServiceFallback implements HelloService {

    @Override
    public String hello() {
        return "error";
    }

    @Override
    public String hello(@RequestParam("name") String name) {
        return "error";
    }

    @Override
    public User hello(@RequestHeader("name") String name, @RequestHeader("age") Integer age) {
        return new User("未知", 0);
    }

    @Override
    public String hello(@RequestBody User user) {
        return "error";
    }

}

另:Feign有继承的特性

@RestController
public class RefactorHelloController implements HelloService {

• 日志的配置

1. 设置全局的日志配置

@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class ConsumerApplication {

    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL;
    }

2. 具体配置

logging.level.com.didispace.web.HelloService=DEBUG

• 各种坑

1. 只要参数是复杂对象，即使指定了GET方法，feign依然会以post方法进行发送请求
2. 不支持多层继承,报 Only single-level inheritance supported
3. 奇葩的FeignClient问题
4. @PathVariable not working with feign ,要写全 @PathVariable 里面的param值
5. eureka里面的/info 端口必须连接的上,否则会报连接超时等错误.
6. ClientAbortException: java.io.IOException: APR error: -730053