Ribbon负载均衡及Feign消费者调用服务
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。
初步应用
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
<!--ribbon相关依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
application.yml加
server:
port:
context-path: / eureka:
client:
service-url:
defaultZone: http://eureka2001.jt.com:2001/eureka/,http://eureka2002.jt.com:2002/eureka/,http://eureka2003.jt.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.jt.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
这里还有一个，要修改下StudentConsumerController的PRE_HOST，改成指定的微服务应用名称；
当然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：
server:
port:
context-path: /
spring:
application:
name: microservice-student
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/xm1?useUnicode=true&characterEncoding=utf8
username: root
password:
jpa:
hibernate:
ddl-auto: update
show-sql: true eureka:
instance:
hostname: localhost #eureka客户端主机实例名称
appname: microservice-student #客户端服务名
instance-id: microservice-student: #客户端实例名称
prefer-ip-address: true #显示IP
client:
service-url:
defaultZone: http://localhost:2001/eureka #把服务注册到eureka注册中心 info:
groupId: com.jt.testSpringcloud
artifactId: microservice-student-provider-
version: 1.0-SNAPSHOT
userName: http://jt.com
phone:
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.jt.microservicestudentconsumer80.controller; import com.jt.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<Student> 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;
}
}
}
上面配置好后，我们可以测试下；
先启动三个eureka，然后再启动服务提供者，再启动服务消费者；
Ribbon负载均衡
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；
新建项目microservice-student-provider-1002，microservice-student-provider-1003
pom.xml，application.yml，以及java类都复制一份，启动类名称对应的改下；
yml配置文件有两处要对应的改下，port端口改下，以及服务实例名称改下；
相关代码如下
相关pom
<?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.</modelVersion>
<parent>
<groupId>com.jt</groupId>
<artifactId>microservice</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<artifactId>microservice-student-provider</artifactId> <properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<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-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
</dependency>
<!-- 修改后立即生效，热部署 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
<dependency>
<groupId>com.jt</groupId>
<artifactId>microservice-common</artifactId>
<version>0.0.-SNAPSHOT</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-netflix-eureka-client</artifactId>
<version>1.4..RELEASE</version>
<scope>compile</scope>
</dependency>
<!--添加注册中心Eureka相关配置-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<!-- actuator监控引入 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build> </project>
Yml文件
---
server:
port:
context-path: /
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/xm1?useUnicode=true&characterEncoding=utf8
username: root
password:
jpa:
hibernate:
ddl-auto: update
show-sql: true
application:
name: microservice-student
profiles: provider- eureka:
instance:
hostname: localhost
appname: microservice-student
instance-id: microservice-student:
prefer-ip-address: true
client:
service-url:
defaultZone: http://eureka2001.jt.com:2001/eureka/,http://eureka2002.jt.com:2002/eureka/,http://eureka2003.jt.com:2003/eureka/ info:
groupId: com.jt.testSpringcloud
artifactId: microservice-student-provider-
version: 1.0-SNAPSHOT
userName: http://jt.com
phone: ---
server:
port:
context-path: /
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/xm1?useUnicode=true&characterEncoding=utf8
username: root
password:
jpa:
hibernate:
ddl-auto: update
show-sql: true
application:
name: microservice-student
profiles: provider- eureka:
instance:
hostname: localhost
appname: microservice-student
instance-id: microservice-student:
prefer-ip-address: true
client:
service-url:
defaultZone: http://eureka2001.jt.com:2001/eureka/,http://eureka2002.jt.com:2002/eureka/,http://eureka2003.jt.com:2003/eureka/ info:
groupId: com.jt.testSpringcloud
artifactId: microservice-student-provider-
version: 1.0-SNAPSHOT
userName: http://jt.com
phone: ---
server:
port:
context-path: /
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/xm1?useUnicode=true&characterEncoding=utf8
username: root
password:
jpa:
hibernate:
ddl-auto: update
show-sql: true
application:
name: microservice-student
profiles: provider- eureka:
instance:
hostname: localhost
appname: microservice-student
instance-id: microservice-student:
prefer-ip-address: true
client:
service-url:
defaultZone: http://eureka2001.jt.com:2001/eureka/,http://eureka2002.jt.com:2002/eureka/,http://eureka2003.jt.com:2003/eureka/ info:
groupId: com.jt.testSpringcloud
artifactId: microservice-student-provider-
version: 1.0-SNAPSHOT
userName: http://jt.com
phone:
启动类
package com.jt.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.jt.*.*")
@EnableEurekaClient
@SpringBootApplication
public class MicroserviceStudentProviderApplication { public static void main(String[] args) {
SpringApplication.run(MicroserviceStudentProviderApplication.class, args);
} }
StudentProviderController.java
package com.jt.microservicestudentprovider.controller; import com.jt.microservicecommon.entity.Student;
import com.jt.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<Student> 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";
}
}
StudentConsumerController.java消费端
package com.jt.microservicestudentconsumer80.controller; import com.jt.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<Student> 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);
}
}
如果是这样的一般没有问题
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
1、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；
修改 microservice-common
pom.xml引入Feign依赖：
<!--引入Feign依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
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；
建StudentClientService接口；
package com.jt.microservicecommon.service; import com.jt.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")
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<Student> 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();
}
2、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
<?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.</modelVersion>
<parent>
<groupId>com.jt</groupId>
<artifactId>microservice</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<artifactId>microservice-student-consumer-feign-</artifactId> <properties>
<java.version>1.8</java.version>
</properties> <dependencies> <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<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-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</dependency>
<!-- 修改后立即生效，热部署 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
<dependency>
<groupId>com.jt</groupId>
<artifactId>microservice-common</artifactId>
<version>0.0.-SNAPSHOT</version>
<scope>compile</scope>
</dependency>
<!--ribbon相关依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency> <!--引入Feign依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
</dependencies> <build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build> </project>
SpringCloudConfig.java
package com.jt.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();
}
}
Yml文件
server:
port:
context-path: /
eureka:
client:
service-url:
defaultZone: http://eureka2001.jt.com:2001/eureka/,http://eureka2002.jt.com:2002/eureka/,http://eureka2003.jt.com:2003/eureka/
register-with-eureka: false
package com.jt.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.jt.*.*")
@SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
public class MicroserviceStudentConsumerFeign80Application { public static void main(String[] args) {
SpringApplication.run(MicroserviceStudentConsumerFeign80Application.class, args);
} }
package com.jt.microservicestudentconsumerfeign80.controller; import com.jt.microservicecommon.entity.Student;
import com.jt.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<Student> 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();
}
}
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