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11.4. FAQ

11.4.1. Feign请求超时

		
方法一,修改配置是让Hystrix的超时时间改为5秒
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds: 5000

方法二,修改配置,禁用Hystrix的超时时间
hystrix.command.default.execution.timeout.enabled: false

方法三,修改配置,用于索性禁用feign的hystrix。
feign.hystrix.enabled: false
		
		

11.4.2. 已停止的微服务节点注销慢或不注销

由于 Eureka Server 清理无效节点周期长默认为90秒,可能会遇到微服务注销慢甚至不注销的问题。

Eureka Server 配置,注意仅适合开发环境。

		
# 设为false, 关闭自我保护, 从而保证会注销微服务
eureka.server.enable-self-preservation=false

# 清理间隔(单位毫秒,默认是60 * 1000)
eureka.server.eviction-interval-timer-in-ms=30000
		
		

Eureka Client

配置开启健康检查,续约更新时间和到期时间。

		
# 设为true,开启健康检查(需要spring-boot-starter-actuator 依赖)
eureka.client.healthcheck.enabled=ture

# 续约更新时间间隔(默认是30秒)
eureka.instance.lease-renewal-interval-in-seconds=20000

# 续约到期时间(默认90秒)
eureka.instance.lease-expiration-duration-in-seconds=30000
		
		

11.4.3. Eureka Client (Dalston.SR1)

11.4.3.1. Maven

			
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>cn.netkiller.spring.cloud</groupId>
	<artifactId>eureka.client</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>eureka.client</name>
	<url>http://maven.apache.org</url>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.3.RELEASE</version>
		<relativePath />
	</parent>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>Dalston.SR1</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-config</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-eureka</artifactId>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-surefire-plugin</artifactId>
				<configuration>
					<skip>true</skip>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>
			
			

11.4.3.2. Application

			
package cn.netkiller.spring.cloud.eureka.client;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
public class Application {
	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}
}
			
			

11.4.3.3. RestController

			
package cn.netkiller.spring.cloud.eureka.client;

import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestRestController {
	private static final Logger logger = LoggerFactory.getLogger(TestRestController.class);

	@RequestMapping("/")
	public String home() {
		logger.info("Hello!!!");
		return "Hello World";
	}

	@Autowired
	private DiscoveryClient discoveryClient;

	@RequestMapping("/service-instances/{applicationName}")
	public List<ServiceInstance> serviceInstancesByApplicationName(@PathVariable String applicationName) {
		return this.discoveryClient.getInstances(applicationName);
	}

	@RequestMapping(value = "/add", method = RequestMethod.GET)
	public Integer add(@RequestParam Integer a, @RequestParam Integer b) {
		@SuppressWarnings("deprecation")
		ServiceInstance instance = discoveryClient.getLocalServiceInstance();
		Integer r = a + b;
		logger.info("/add, host:" + instance.getHost() + ", service_id:" + instance.getServiceId() + ", result:" + r);
		return r;
	}
	
	@RequestMapping("/greeting")
	public String greeting() {
		return "GREETING";
	}
}
			
			
			

11.4.3.4. application.properties

			
spring.application.name=test-service
server.port=8080
eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka/			
			
			

11.4.3.5. 测试

首先确认客户端已经注册到 http://localhost:8761/

			
$ curl http://localhost:8080/service-instances/test-service

[
	{
		"host": "Neo-Desktop",
		"port": 8080,
		"secure": false,
		"uri": "http://Neo-Desktop:8080",
		"serviceId": "TEST-SERVICE",
		"metadata": {},
		"instanceInfo": {
			"instanceId": "Neo-Desktop:test-service:8080",
			"app": "TEST-SERVICE",
			"appGroupName": null,
			"ipAddr": "172.25.10.150",
			"sid": "na",
			"homePageUrl": "http://Neo-Desktop:8080/",
			"statusPageUrl": "http://Neo-Desktop:8080/info",
			"healthCheckUrl": "http://Neo-Desktop:8080/health",
			"secureHealthCheckUrl": null,
			"vipAddress": "test-service",
			"secureVipAddress": "test-service",
			"countryId": 1,
			"dataCenterInfo": {
			"@class": "com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo",
			"name": "MyOwn"
		},
		"hostName": "Neo-Desktop",
		"status": "UP",
		"leaseInfo": {
			"renewalIntervalInSecs": 30,
			"durationInSecs": 90,
			"registrationTimestamp": 1497922681680,
			"lastRenewalTimestamp": 1497922681680,
			"evictionTimestamp": 0,
			"serviceUpTimestamp": 1497922003783
		},
		"isCoordinatingDiscoveryServer": false,
		"metadata": {},
		"lastUpdatedTimestamp": 1497922681680,
		"lastDirtyTimestamp": 1497922681025,
		"actionType": "ADDED",
		"asgName": null,
		"overriddenStatus": "UNKNOWN"
		}
	}
]
			
			

add 接口测试

			
curl http://localhost:8080/add.json?a=5&b=3

8			
			
			

11.4.4. Feign 启动出错 PathVariable annotation was empty on param 0.

问题分析,@PathVariable 找不到对应的参数

		
package api.feign;

import java.util.List;
import java.util.Map;

import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

@FeignClient("restful-api-service")
public interface Search {
	
	@RequestMapping("/search/article/list")
	public List<Map<String, Object>> list();
	
	@RequestMapping("/search/article/{articleId}")
	public Object read(@PathVariable String articleId);
}		
		
		

解决方案

		
	@RequestMapping("/search/article/{articleId}")
	public Object read(@PathVariable("articleId") String articleId);
		
		

11.4.5. Feign 提示 Consider defining a bean of type 'common.feign.Cms' in your configuration.

背景:我们需要共用 Feign 接口,故将 Feign 放到共用的 common-version.jar 包中,供其他项目使用。

启动提示:Consider defining a bean of type 'common.feign.Cms' in your configuration.

注解加入包位置后解决

		
@EnableFeignClients("common.feign")		
		
		

例 11.1. Share feign interface.

			
package cn.netkiller.feign;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients("common.feign")
public class Application {

	public static void main(String[] args) {
		System.out.println("Feign Starting...");
		SpringApplication.run(Application.class, args);
	}
}