Spring cloud 之 Feign Client
时间:2022-05-03
本文章向大家介绍Spring cloud 之 Feign Client,主要内容包括12.2.2. Eureka Client、12.2.2.2. Application、12.2.2.3. RestController、12.2.2.4. application.properties、12.2.2.5. 测试、12.2.3. Feign client、12.2.3.2. Application、12.2.3.3. interface、12.2.3.4. application.properties、12.2.3.5. 测试、基本概念、基础应用、原理机制和需要注意的事项等,并结合实例形式分析了其使用技巧,希望通过本文能帮助到大家理解应用这部分内容。
本文接选自 《Netkiller Java 手札》
12.2.2. Eureka Client
12.2.2.1. 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>
12.2.2.2. 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);
}
}
12.2.2.3. 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";
}
}
12.2.2.4. application.properties
spring.application.name=test-service
server.port=8080
eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka/
12.2.2.5. 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
12.2.3. Feign client
12.2.3.1. 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.netflix</groupId>
<artifactId>feign.client</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>feign.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>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
<version>1.3.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
<version>1.3.1.RELEASE</version>
</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>
12.2.3.2. Application
package cn.netkiller.spring.cloud.netflix.feign.client;
import org.springframework.beans.factory.annotation.Autowired;
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;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients
@RestController
public class Application {
@Autowired
private GreetingClient greetingClient;
@RequestMapping("/get-greeting")
public String greeting() {
return greetingClient.greeting();
}
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
System.out.println("Hello World!");
}
}
12.2.3.3. interface
package cn.netkiller.spring.cloud.netflix.feign.client;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
@FeignClient("test-service")
public interface GreetingClient {
@RequestMapping("/greeting")
String greeting();
}
@FeignClient("test-service") 是 Eureka Client application.properties 中的 spring.application.name 配置项
@RequestMapping("/greeting") 是 Eureka Client RestController 中的 @RequestMapping
12.2.3.4. application.properties
spring.application.name=spring-cloud-eureka-feign-client
server.port=8088
#eureka.client.register-with-eureka=false
#eureka.client.fetch-registry=false
eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka/
feign.compression.response.enabled=true
feign.compression.request.enabled=true
feign.compression.request.mime-types=text/xml,application/xml,application/json
feign.compression.request.min-request-size=2048
12.2.3.5. 测试
$ curl -s http://localhost:8088/get-greeting.json
GREETING
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