(四)Spring Cloud Feign 声明式调用
上一章讲了Ribbon的负载均衡,并且使用RestTemplate进行了调用,本章讲解另外一种负载均衡的调用
即,Feign的声明式调用
和上一章一样,我们将启动1个eureka-server 用于服务的注册,2个eureka-client 模拟2个客户端 1个 eureka-feign-client 用于对客户端的声明式调用
1. 创建一个maven项目
在pom中设置
<packaging>pom</packaging>
2. 新建eureka-server,端口为7001
主要配置如下
2.1 pom文件
<?xml version="1.0" encoding="UTF-8"?> <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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.2.5.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.devin</groupId> <artifactId>eureka-server</artifactId> <version>0.0.1-SNAPSHOT</version> <name>eureka-server</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> <spring-cloud.version>Hoxton.SR3</spring-cloud.version> </properties> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-security</artifactId> <scope>compile</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-sleuth</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> <exclusions> <exclusion> <groupId>org.junit.vintage</groupId> <artifactId>junit-vintage-engine</artifactId> </exclusion> </exclusions> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>${spring-cloud.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
2.2. 启动类
package com.devin.eurekaserver; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer; @EnableEurekaServer @SpringBootApplication public class EurekaServerApplication { public static void main(String[] args) { SpringApplication.run(EurekaServerApplication.class, args); } }
2.3 权限配置类
package com.devin.eurekaserver.config; import org.springframework.security.config.annotation.web.builders.HttpSecurity; import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity; import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter; @EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { //关闭csrf super.configure(http); //开启认证 http.csrf().disable(); } }
2.4 application.yml 配置
eureka-server 的启动端口为 7001
server:
port: 7001 #启动端口
spring:
#应用名称
application:
name: eureka-server
#安全配置
security:
basic:
enabled: true
user:
name: dev
password: 123456
#eureka配置
eureka:
server:
#设置扫描失效服务的间隔时间
eviction-interval-timer-in-ms: 20000
enable-self-preservation: true
instance:
hostname: localhost
leaseRenewalIntervalInSeconds: 10
health-check-url-path: /actuator/health
client:
register-with-eureka: false #false:不作为一个客户端注册到注册中心
fetch-registry: false #为true时,可以启动,但报异常:Cannot execute request on any known server
service-url:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
# health endpoint是否必须显示全部细节。默认情况下, /actuator/health 是公开的,并且不显示细节。
# 设置actuator开关
management:
security:
enabled: false
endpoints:
web:
exposure:
include: "*"
endpoint:
health:
show-details: ALWAYS
3. eureka-client 配置
3.1 pom.xml配置
<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <version>2.1.8.RELEASE</version> </dependency>
3.2 启动类
package com.devin.eurekaclient; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; @EnableEurekaClient @SpringBootApplication public class EurekaClientApplication { public static void main(String[] args) { SpringApplication.run(EurekaClientApplication.class, args); } }
3.3 新建Controller
在controller中定义了一个get和一个post请求的方法
package com.devin.eurekaclient.controller; import com.devin.eurekaclient.vo.User; import org.springframework.beans.factory.annotation.Value; import org.springframework.web.bind.annotation.*; /** * @author Devin Zhang * @className HelloController * @description TODO * @date 2020/3/28 10:45 */ @RestController public class HelloController { @Value("${server.port}") private Integer port; @GetMapping("/sayHello") public String sayHello(String name) { return "Hello ," + name + " ,this response is from eureka client port:" + port; } @PostMapping("/login") public String login(@RequestBody User user) { if (user.getUserName().equals("devin") && user.getUserPass().equals("123456")) { return "success from " + port; } return "fail from " + port; } }
对应的model
package com.devin.eurekaclient.vo; /** * @author Devin Zhang * @className User * @description TODO * @date 2020/3/30 13:33 */ public class User { private String userName; private String userPass; public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getUserPass() { return userPass; } public void setUserPass(String userPass) { this.userPass = userPass; } }
3.4 application.yml 配置文件
后续eureka-client将启动2个端口 7002 和 7003 ,这两个实例将分别在eueka-server 7001 注册
eureka: auth: user: dev password: 123456 client: serviceUrl: defaultZone: http://${eureka.auth.user}:${eureka.auth.password}@localhost:7001/eureka/ instance: #使用IP进行注册 prefer-ip-address: true #配置实例的注册ID instance-id: ${spring.cloud.client.ip-address}:${server.port} #心跳时间,即服务续约间隔时间(缺省为30s) lease-renewal-interval-in-seconds: 5 #发呆时间,即服务续约到期时间(缺省为90s) lease-expiration-duration-in-seconds: 10 health-check-url-path: /actuator/health server: port: 7002 spring: application: name: eureka-client
4. eureka-feign-client
通过feign去调用eureka-client,feign将自动实现客户端服务调用的负载均衡
4.1 pom.xml
<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> <version>2.1.1.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <version>2.1.8.RELEASE</version> </dependency> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.3</version> </dependency> <dependency> <groupId>io.github.openfeign</groupId> <artifactId>feign-httpclient</artifactId> <version>10.1.0</version> </dependency>
ps: 后面两个包是为了解决feign的get请求时会报如下错误,同时需要在配置文件中添加 feign.httpclient.enabled=true
{"timestamp":"2020-03-30T02:03:50.634+0000","status":405,"error":"Method Not Allowed","message":"Request method 'POST' not supported",
4.2 启动类
该项目也作为一个client在服务端7001 注册
package com.devin.eurekafeignclient; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; import org.springframework.cloud.openfeign.EnableFeignClients; @SpringBootApplication @EnableEurekaClient @EnableFeignClients public class EurekaFeignClientApplication { public static void main(String[] args) { SpringApplication.run(EurekaFeignClientApplication.class, args); } }
4.3 Feign的配置类
package com.devin.eurekafeignclient.config; import feign.Retryer; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import static java.util.concurrent.TimeUnit.SECONDS; /** * @author Devin Zhang * @className FeignConfig * @description TODO * @date 2020/3/28 16:50 */ @Configuration public class FeignConfig { @Bean public Retryer feignRetryer() { return new Retryer.Default(100, SECONDS.toSeconds(1), 5); } }
4.4 Feign去声明式调用eureka-clent的接口服务
feign将去调用我们再eureka-client中定义的get和post对应的接口
package com.devin.eurekafeignclient.service; import com.devin.eurekafeignclient.config.FeignConfig; import com.devin.eurekafeignclient.vo.User; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestParam; /** * @author Devin Zhang * @className FeignHelloService * @description TODO * @date 2020/3/28 16:49 */ @FeignClient(value = "eureka-client", configuration = FeignConfig.class) public interface FeignHelloService { @GetMapping(value = "/sayHello") String sayHello(@RequestParam String name); @PostMapping(value = "/login", consumes = "application/json") String login(@RequestBody User user); }
package com.devin.eurekafeignclient.vo; /** * @author Devin Zhang * @className User * @description TODO * @date 2020/3/30 13:39 */ public class User { private String userName; private String userPass; public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getUserPass() { return userPass; } public void setUserPass(String userPass) { this.userPass = userPass; } }
4.5 controller测试类
package com.devin.eurekafeignclient.controller; import com.devin.eurekafeignclient.service.FeignHelloService; import com.devin.eurekafeignclient.vo.User; import org.springframework.http.MediaType; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; import javax.annotation.Resource; /** * @author Devin Zhang * @className FeignHelloController * @description TODO * @date 2020/3/28 17:01 */ @RestController public class FeignHelloController { @Resource private FeignHelloService feignHelloService; @GetMapping(value = "/sayHelloFromFeign") public String sayHelloFromFeign(String name) { return feignHelloService.sayHello(name); } @PostMapping(value = "/loginFromFeign") public String sayHelloFromFeign(User user) { return feignHelloService.login(user); } }
4.6 eureka-feign-client application.yml 配置
feigin client 7004 将在eureka-server 7001注册
eureka:
auth:
user: dev
password: 123456
client:
serviceUrl:
defaultZone: http://${eureka.auth.user}:${eureka.auth.password}@localhost:7001/eureka/
instance:
#使用IP进行注册
prefer-ip-address: true
#配置实例的注册ID
instance-id: ${spring.cloud.client.ip-address}:${server.port}
#心跳时间,即服务续约间隔时间(缺省为30s)
lease-renewal-interval-in-seconds: 5
#发呆时间,即服务续约到期时间(缺省为90s)
lease-expiration-duration-in-seconds: 10
health-check-url-path: /actuator/health
server:
port: 7004
spring:
application:
name: eureka-feign-client
feign:
httpclient:
enabled: true
5. 测试
启动 eureka-server 7001
启动eureka-client 7002,7003
java -jar eureka-client-0.0.1-SNAPSHOT.jar --server.port=7002
java -jar eureka-client-0.0.1-SNAPSHOT.jar --server.port=7003
启动 eureka-feign-client 7004
服务的注册情况如下:
验证
访问get请求 http://localhost:7004/sayHelloFromFeign?name=devin 可以看到调用的eureka-clent在7002和7003之间进行切换
Post请求,使用 SoupUI发送post请求,可以看到后端收到参数,自动封装为一个model,返回结果,并且在7002,7003之间负载均衡
至此,feign的声明式调用完成。