springcloud的Eureka服务提供者的集群搭建和消费者调用Ribbon和Feign
微服务调用Ribbon
简介
前面讲了eureka服务注册与发现，但是结合eureka集群的服务调用没讲。
这里的话 就要用到Ribbon，结合eureka，来实现服务的调用；
Ribbon是Netflix发布的负载均衡器，它有助于控制HTTP和TCP的客户端的行为。为Ribbon配置服务提供者地址后，Ribbon就可基于某种负载均衡算法，自动地帮助服务消费者去请求。Ribbon默认为我们提供了很多负载均衡算法，例如轮询、随机等。当然，我们也可为Ribbon实现自定义的负载均衡算法。
在Spring Cloud中，当Ribbon与Eureka配合使用时，Ribbon可自动从Eureka Server获取服务提供者地址列表，并基于负载均衡算法，请求其中一个服务提供者实例。展示了Ribbon与Eureka配合使用时的架构。
Ribbon 使用
消费者端
Ribbon是客户端负载均衡，所以肯定集成再消费端，也就是consumer端
我们修改microservice-student-consumer-80
首先，引入依赖，pom.xml 加入 ribbon相关依赖
org.springframework.cloud
spring-cloud-starter-eureka
org.springframework.cloud
spring-cloud-starter-ribbon
org.springframework.cloud
spring-cloud-starter-config
在消费者的application.yml配置
server:
port: 80
context-path: /
eureka:
client:
service-url:
defaultZone: http://eureka2001.thf.com:2001/eureka/,http://eureka2002.thf.com:2002/eureka/,http://eureka2003.thf.com:2003/eureka/
register-with-eureka: false
ribbon结合eureka来调用服务提供者；
SpringCloudConfig也改成 要加个负载均衡配置 @LoadBalanced
package com.thf.microservicestudentconsumer80.config;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
@Configuration
public class SpringCloudConfig {
@LoadBalanced // 引入ribbon负载均衡
@Bean
public RestTemplate getRestTemplate(){
return new RestTemplate();
}
}
因为和eureka整合，所以启动类StudentConsumerApplication_80 加个注解 @EnableEurekaClient
package com.thf.microservicestudentconsumer80;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@EnableEurekaClient
@SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
public class MicroserviceStudentConsumer80Application {
public static void main(String[] args) {
SpringApplication.run(MicroserviceStudentConsumer80Application.class, args);
}
}
StudentConsumerController
我们的微服务应用名称是 microservice-student
所以服务调用者这边的控制器里PRE_HOST改成 http://MICROSERVICE-STUDENT即可；
MICROSERVICE-STUDENT为Eureka注册中心的应用名称
package com.thf.microservicestudentconsumer80.controller;
import com.thf.microservicecommon.entity.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;
import java.util.List;
@RestController
@RequestMapping("/student")
public class StudentConsumerController {
private final static String SERVER_IP_PORT = "http://MICROSERVICE-STUDENT";
@Autowired
private RestTemplate restTemplate;
@PostMapping(value = "/save")
private boolean save(Student student) {
return restTemplate.postForObject(SERVER_IP_PORT + "/student/save", student, Boolean.class);
}
@GetMapping(value = "/list")
public List list() {
return restTemplate.getForObject(SERVER_IP_PORT + "/student/list", List.class);
}
@GetMapping(value = "/get/{id}")
public Student get(@PathVariable("id") Integer id) {
return restTemplate.getForObject(SERVER_IP_PORT + "/student/get/" + id, Student.class);
}
@GetMapping(value = "/delete/{id}")
public boolean delete(@PathVariable("id") Integer id) {
try {
restTemplate.getForObject(SERVER_IP_PORT + "/student/delete/" + id, Boolean.class);
return true;
} catch (Exception e) {
return false;
}
}
@RequestMapping("/ribbon")
public String ribbon() {
return restTemplate.getForObject(SERVER_IP_PORT + "/student/ribbon", String.class);
}
}
这个是服务端的调用名，也就是对应
这里要先在服务提供者microservice-student-provider-1001的application.yml加下配置，指定下应用名称：
application:
name: microservice-student
Ribbon负载均衡
服务端配置
按照它microservice-student-provider-1001建立一个microservice-student-provider子项目，然后将microservice-student-provider-1001这个子项目干掉；
前面搭建了初步例子，但是还没实现真正负载均衡，我们这里要先搞三个服务提供者集群，然后才能演示负载均衡，以及负载均衡策略；
pom.xml
4.0.0
com.thf
T226microservice
1.0-SNAPSHOT
microservice-student-provider
1.8
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-test
test
org.springframework.boot
spring-boot-starter-data-jpa
mysql
mysql-connector-java
org.springframework.boot
spring-boot-starter-tomcat
com.alibaba
druid-spring-boot-starter
org.springframework
springloaded
org.springframework.boot
spring-boot-devtools
com.thf
microservice-common
1.0-SNAPSHOT
compile
org.springframework.cloud
spring-cloud-starter-eureka
org.springframework.cloud
spring-cloud-starter-config
org.springframework.boot
spring-boot-starter-actuator
org.springframework.boot
spring-boot-maven-plugin
application.yml
---
server:
port: 1001
context-path: /
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/t226-thf?useUnicode=true&characterEncoding=utf8
username: root
password: 123
jpa:
hibernate:
ddl-auto: update
show-sql: true
application:
name: microservice-student
profiles: provider-1001
eureka:
instance:
hostname: localhost
appname: microservice-student
instance-id: microservice-student:1001
prefer-ip-address: true
client:
service-url:
defaultZone: http://eureka2001.thf.com:2001/eureka/,http://eureka2002.thf.com:2002/eureka/,http://eureka2003.thf.com:2003/eureka/
info:
groupId: com.thf.testSpringcloud
artifactId: microservice-student-provider-1001
version: 1.0-SNAPSHOT
userName: http://thf.com
phone: 123456
---
server:
port: 1002
context-path: /
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/t226-thf?useUnicode=true&characterEncoding=utf8
username: root
password: 123
jpa:
hibernate:
ddl-auto: update
show-sql: true
application:
name: microservice-student
profiles: provider-1002
eureka:
instance:
hostname: localhost
appname: microservice-student
instance-id: microservice-student:1002
prefer-ip-address: true
client:
service-url:
defaultZone: http://eureka2001.thf.com:2001/eureka/,http://eureka2002.thf.com:2002/eureka/,http://eureka2003.thf.com:2003/eureka/
info:
groupId: com.thf.testSpringcloud
artifactId: microservice-student-provider-1002
version: 1.0-SNAPSHOT
userName: http://thf.com
phone: 123456
---
server:
port: 1003
context-path: /
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/t226-thf?useUnicode=true&characterEncoding=utf8
username: root
password: 123
jpa:
hibernate:
ddl-auto: update
show-sql: true
application:
name: microservice-student
profiles: provider-1003
eureka:
instance:
hostname: localhost
appname: microservice-student
instance-id: microservice-student:1003
prefer-ip-address: true
client:
service-url:
defaultZone: http://eureka2001.thf.com:2001/eureka/,http://eureka2002.thf.com:2002/eureka/,http://eureka2003.thf.com:2003/eureka/
info:
groupId: com.thf.testSpringcloud
artifactId: microservice-student-provider-1003
version: 1.0-SNAPSHOT
userName: http://thf.com
phone: 123456
启动类（ MicroserviceStudentProviderApplication）
package com.thf.microservicestudentprovider;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@EntityScan("com.thf.*.*")
@EnableEurekaClient
@SpringBootApplication
public class MicroserviceStudentProviderApplication {
public static void main(String[] args) {
SpringApplication.run(MicroserviceStudentProviderApplication.class, args);
}
}
controller层
处理消费者发过来的请求
package com.thf.microservicestudentprovider.controller;
import com.thf.microservicecommon.entity.Student;
import com.thf.microservicestudentprovider.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
@RequestMapping("/student")
public class StudentProviderController {
@Autowired
private StudentService studentService;
@Value("${server.port}")
private String port;
@PostMapping(value="/save")
public boolean save(Student student){
try{
studentService.save(student);
return true;
}catch(Exception e){
return false;
}
}
@GetMapping(value="/list")
public List list(){
return studentService.list();
}
@GetMapping(value="/get/{id}")
public Student get(@PathVariable("id") Integer id){
return studentService.findById(id);
}
@GetMapping(value="/delete/{id}")
public boolean delete(@PathVariable("id") Integer id){
try{
studentService.delete(id);
return true;
}catch(Exception e){
return false;
}
}
@RequestMapping("/ribbon")
public String ribbon(){
return "工号【"+port+"】正在为您服务";
}
}
接下来我们测试一下：
首先我们配置一下：
测试：
开启 eureka 集群，开启服务提供者集群、开启消费者，下面是eureka 中显示的结果
客户端调用：
多刷新几次 看结果，我们看到 有默认的轮询策略，访问对应的服务提供者；
但是这种默认的轮询策略肯定是不能满足实际需求的，比如有3个服务提供者，突然挂了一个
比如我把一个1002服务挂掉，我们看一下结果：
这样的话，默认轮询 ，总有1/3的概率访问失败； 所以我们看下ribbon默认给我们提供的策略有哪些；
默认7个策略，根据具体产品需求选用；代码中通过如下方法指定：
这里我们演示用 RetryRule，大伙可以自行测试;
服务消费端 SpringCloudConfig配置类
package com.thf.microservicestudentconsumer80.config;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
@Configuration
public class SpringCloudConfig {
@LoadBalanced // 引入ribbon负载均衡
@Bean
public RestTemplate getRestTemplate(){
return new RestTemplate();
}
}
这样就欧克啦！！
Feign简介及应用
简介
声明式服务调用Feign简单介绍下；
Feign是一个声明式的Web Service客户端，它使得编写Web Serivce客户端变得更加简单。我们只需要使用Feign来创建一个接口并用注解来配置它既可完成。它具备可插拔的注解支持，包括Feign注解和JAX-RS注解。Feign也支持可插拔的编码器和解码器。Spring Cloud为Feign增加了对Spring MVC注解的支持，还整合了Ribbon和Eureka来提供均衡负载的HTTP客户端实现。
这段话看起来比较懵逼，这里说下实际使用，前面Ribbon调用服务提供者，我们通过restTemplate调用，缺点是，多个地方调用，同一个请求要写多次，不方便统一维护，这时候Feign来了，就直接把请求统一搞一个service作为FeignClient，然后其他调用Controller需要用到的，直接注入service，直接调用service方法即可；同时Feign整合了Ribbon和Eureka，所以要配置负载均衡的话，直接配置Ribbon即可，无其他特殊地方；当然Fiegn也整合了服务容错保护，断路器Hystrix，后面再说。
应用
修改 microservice-common （项目通用模块）
在common项目里建一个service（实际项目肯定是多个service）作为Feign客户端，用Feign客户端来调用服务器提供者，当然可以配置负载均衡；Feign客户端定义的目的，就是为了方便给其他项目调用
pom.xml引入Feign依赖：
org.springframework.cloud
spring-cloud-starter-feign
我们定义了 FeignClient，同时指定了调用的服务名称MICROSERVICE-STUDENT
common项目修改后，maven clean下 然后install下；
StudentClientService 这个就是要使用到注入的service 层
package com.thf.microservicecommon.service;
import com.thf.microservicecommon.entity.Student;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import java.util.List;
/**
* Student Feign接口客户端
* @author Administrator
*
*/
@FeignClient(value="MICROSERVICE-STUDENT") //被调用方服务名
public interface StudentClientService {
/**
* 根据id查询学生信息
* @param id
* @return
*/
@GetMapping(value="/student/get/{id}")
public Student get(@PathVariable("id") Integer id);
/**
* 查询学生信息
* @return
*/
@GetMapping(value="/student/list")
public List list();
/**
* 添加或者修改学生信息
* @param student
* @return
*/
@PostMapping(value="/student/save")
public boolean save(Student student);
/**
* 根据id删除学生信息
* @return
*/
@GetMapping(value="/student/delete/{id}")
public boolean delete(@PathVariable("id") Integer id);
@RequestMapping("/student/ribbon")
public String ribbon();
}
新建一个Feign消费者项目；
参考microservice-student-consumer-80建一个microservice-student-consumer-feign-80
代码都复制一份，包括pom.xml
pom.xml
4.0.0
com.thf
T226microservice
1.0-SNAPSHOT
microservice-student-consumer-feign-80
1.8
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-test
test
org.springframework.boot
spring-boot-starter-data-jpa
mysql
mysql-connector-java
org.springframework.boot
spring-boot-starter-tomcat
org.springframework
springloaded
org.springframework.boot
spring-boot-devtools
com.thf
microservice-common
1.0-SNAPSHOT
compile
org.springframework.cloud
spring-cloud-starter-eureka
org.springframework.cloud
spring-cloud-starter-ribbon
org.springframework.cloud
spring-cloud-starter-config
org.springframework.cloud
spring-cloud-starter-feign
org.springframework.boot
spring-boot-maven-plugin
注意：这个Feign消费者项目里面，pom.xml要引入Feign依赖
SpringCloudConfig(解决Ribbon轮询问题)
package com.thf.microservicestudentconsumerfeign80.config;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RetryRule;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
@Configuration
public class SpringCloudConfig {
@LoadBalanced // 引入ribbon负载均衡
@Bean
public RestTemplate getRestTemplate(){
return new RestTemplate();
}
/**
* 自定义调用规则（服务提供者掉线后不再调用，解决轮询问题）
* @return
*/
@Bean
public IRule myRule(){
return new RetryRule();
// return new RandomRule();
}
}
StudentConsumerController
package com.thf.microservicestudentconsumerfeign80.controller;
;
import com.thf.microservicecommon.entity.Student;
import com.thf.microservicecommon.service.StudentClientService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;
import java.util.List;
@RestController
@RequestMapping("/student")
public class StudentConsumerController {
@Autowired
private StudentClientService studentClientService;
@Autowired
private RestTemplate restTemplate;
@PostMapping(value = "/save")
private boolean save(Student student) {
return studentClientService.save(student);
}
@GetMapping(value = "/list")
public List list() {
return studentClientService.list();
}
@GetMapping(value = "/get/{id}")
public Student get(@PathVariable("id") Integer id) {
return studentClientService.get(id);
}
@GetMapping(value = "/delete/{id}")
public boolean delete(@PathVariable("id") Integer id) {
try {
studentClientService.delete(id);
return true;
} catch (Exception e) {
return false;
}
}
@RequestMapping("/ribbon")
public String ribbon(){
return studentClientService.ribbon();
}
}
启动类配置：
package com.thf.microservicestudentconsumerfeign80;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
@EnableEurekaClient
@EnableFeignClients(value = "com.thf.*.*")
@SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
public class MicroserviceStudentConsumerFeign80Application {
public static void main(String[] args) {
SpringApplication.run(MicroserviceStudentConsumerFeign80Application.class, args);
}
}
测试
因为现在用Fiegn，所以把restTemplate去掉，改成注入service，调用service方法来实现服务的调用；
调用的时候我们发现同样是实现的负载均衡
这个是你挂掉了一个服务，不会出现访问不而报错
！！！