微服務調用Ribbon負載均衡及Feign的使用

文章目錄

微服務調用Ribbon

什麼是Ribbon？我們來了解一下
Ribbon是Netflix發佈的負載均衡器，它有助於控制HTTP和TCP的客戶端的行爲。爲Ribbon配置服務提供者地址後，Ribbon就可基於某種負載均衡算法，自動地幫助服務消費者去請求。Ribbon默認爲我們提供了很多負載均衡算法，例如輪詢、隨機等。當然，我們也可爲Ribbon實現自定義的負載均衡算法。
在Spring Cloud中，當Ribbon與Eureka配合使用時，Ribbon可自動從Eureka Server獲取服務提供者地址列表，並基於負載均衡算法，請求其中一個服務提供者實例。展示了Ribbon與Eureka配合使用時的架構

修改microservice-student-consumer-80的部分

pom.xml

<!--ribbon相關依賴-->
        <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中加上Eureka的配置

消費者不需要註冊到eureka,所以register-with-eureka: false

eureka:
  client:
    service-url:
      defaultZone: http://eureka2001.tzj.com:2001/eureka/,http://eureka2002.tzj.com:2002/eureka/,http://eureka2003.tzj.com:2003/eureka/
    register-with-eureka: false

SpringCloudConfig配置類中加上註解

package com.tzj.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負載均衡
    @Bean
    public RestTemplate getRestTemplate(){
        return new RestTemplate();
    }
}

在啓動類加

@EnableEurekaClient

修改StudentConsumerController

我們的微服務應用名稱是 microservice-student
MICROSERVICE-STUDENT爲Eureka註冊中心的應用名稱

MICROSERVICE-STUDENT 要大寫！！！因爲在eureka的控制中心顯示的是大寫的

    private final static String SERVER_IP_PORT = "http://MICROSERVICE-STUDENT";

測試

Ribbon負載均衡

前面搭建了初步例子，但是還沒實現真正負載均衡，我們這裏要先搞三個服務提供者集羣，然後才能演示負載均衡，以及負載均衡策略
Ribbon負載均衡的作用就是減輕服務器壓力，若1000個請求同時在一個服務器上，那樣服務器壓力會很重，利用集羣，分佈在三個服務器上，這樣就減輕了壓力，另外也解決了當一個服務器出現故障

microservice-student-provider
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>4.0.0</modelVersion>
    <parent>
        <groupId>com.tzj</groupId>
        <artifactId>springcloud1</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <artifactId>microservice-student-provider</artifactId>

    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>com.tzj</groupId>
            <artifactId>microservice-common</artifactId>
        </dependency>
        <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>
        <!--  修改後立即生效，熱部署  -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>springloaded</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
        <dependency>
            <groupId>com.tzj</groupId>
            <artifactId>microservice-common</artifactId>
            <version>1.0-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>

        <!--添加註冊中心Eureka相關配置-->
        <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監控引入 -->
        <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: 1001
  context-path: /
spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mysql?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.tzj.com:2001/eureka/,http://eureka2002.tzj.com:2002/eureka/,http://eureka2003.tzj.com:2003/eureka/

info:
  groupId: com.tzj.springcloud1
  artifactId: microservice-student-provider-1001
  version: 1.0-SNAPSHOT
  userName: http://tzj.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/mysql?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.tzj.com:2001/eureka/,http://eureka2002.tzj.com:2002/eureka/,http://eureka2003.tzj.com:2003/eureka/

info:
  groupId: com.tzj.springcloud1
  artifactId: microservice-student-provider-1002
  version: 1.0-SNAPSHOT
  userName: http://tzj.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/mysql?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.tzj.com:2001/eureka/,http://eureka2002.tzj.com:2002/eureka/,http://eureka2003.tzj.com:2003/eureka/

info:
  groupId: com.tzj.springcloud1
  artifactId: microservice-student-provider-1003
  version: 1.0-SNAPSHOT
  userName: http://tzj.com
  phone: 123456

將之前microservice-student-provider-1001項目中的controller，service，repository三個包複製過來

啓動類MicroserviceStudentProviderApplication

package com.tzj.microservicestudentprovider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@EntityScan("com.tzj.*.*")
@EnableEurekaClient
@SpringBootApplication
public class MicroserviceStudentProviderApplication {

    public static void main(String[] args) {
        SpringApplication.run(MicroserviceStudentProviderApplication.class, args);
    }
}

microservice-student-provider的StudentProviderController

@Value("${server.port}")
private String port;

@RequestMapping("/ribbon")
public String ribbon(){
    return "工號【"+port+"】正在爲您服務";
}

microservice-student-consumer-80的StudentConsumerController

@RequestMapping("/ribbon")
public String ribbon(){
    return restTemplate.getForObject(SERVER_IP_PORT + "/student/ribbon", String.class);

頁面請求可以看到，我們每次刷新請求都會換一個端口

但是當我們有一個服務器宕機了，當輪迴到這個服務器時，它不會自動幫我們跳過（好像有新版本已經解決這個問題了），而是會出現404，所以這就需要我們更改它的默認算法
我們在服務消費端（microservice-student-consumer-80）SpringCloudConfig中加一個配置即可

Feign簡介及應用

簡介

Feign是一個聲明式的Web Service客戶端，它使得編寫Web Serivce客戶端變得更加簡單。我們只需要使用Feign來創建一個接口並用註解來配置它既可完成。它具備可插拔的註解支持，包括Feign註解和JAX-RS註解。Feign也支持可插拔的編碼器和解碼器。Spring Cloud爲Feign增加了對Spring MVC註解的支持，還整合了Ribbon和Eureka來提供均衡負載的HTTP客戶端實現。

這段話看起來比較懵逼，這裏說下實際使用，前面Ribbon調用服務提供者，我們通過restTemplate調用，缺點是，多個地方調用，同一個請求要寫多次，不方便統一維護，這時候Feign來了，就直接把請求統一搞一個service作爲FeignClient，然後其他調用Controller需要用到的，直接注入service，直接調用service方法即可；同時Feign整合了Ribbon和Eureka，所以要配置負載均衡的話，直接配置Ribbon即可，無其他特殊地方；當然Fiegn也整合了服務容錯保護，斷路器Hystrix，後面再說

microservice-common的pom.xml引入Feign依賴：

<!--引入Feign依賴-->
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-feign</artifactId>
</dependency>

StudentClientService

package com.tzj.microservicecommon.service;

import com.tzj.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接口客戶端
 * @author Administrator
 *
 */
@FeignClient(value="MICROSERVICE-STUDENT")
public interface StudentClientService {
 
    /**
     * 根據id查詢學生信息
     * @param id
     * @return
     */
    @GetMapping(value="/student/get/{id}")
    public Student get(@PathVariable("id") Integer id);
     
    /**
     * 查詢學生信息
     * @return
     */
    @GetMapping(value="/student/list")
    public List<Student> list();
     
    /**
     * 添加或者修改學生信息
     * @param student
     * @return
     */
    @PostMapping(value="/student/save")
    public boolean save(Student student);
     
    /**
     * 根據id刪除學生信息
     * @return
     */
    @GetMapping(value="/student/delete/{id}")
    public boolean delete(@PathVariable("id") Integer id);

    @RequestMapping("/student/ribbon")
    public String ribbon();
}

新建消費者項目（microservice-student-consumer-feign-80）

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>4.0.0</modelVersion>
    <parent>
        <groupId>com.tzj</groupId>
        <artifactId>springcloud1</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <artifactId>microservice-student-consumer-feign-80</artifactId>

    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>com.tzj</groupId>
            <artifactId>microservice-common</artifactId>
        </dependency>
        <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>
        <!--  修改後立即生效，熱部署  -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>springloaded</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
        <dependency>
            <groupId>com.tzj</groupId>
            <artifactId>microservice-common</artifactId>
            <version>1.0-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>

        <!--ribbon相關依賴-->
        <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依賴-->
        <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

package com.tzj.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負載均衡
    @Bean
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }

    /**
     * 自定義調用規則（服務提供者掉線後不再調用，解決輪詢問題）
     * @return
     */
    @Bean
    public IRule myRule(){
        return new RetryRule();
//        return new RandomRule();
    }
}

yml文件

server:
  port: 80
  context-path: /
eureka:
  client:
    service-url:
      defaultZone: http://eureka2001.tzj.com:2001/eureka/,http://eureka2002.tzj.com:2002/eureka/,http://eureka2003.tzj.com:2003/eureka/
    register-with-eureka: false

**啓動類MicroserviceStudentConsumerFeign80Application **

package com.tzj.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.tzj.*.*")
@SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
public class MicroserviceStudentConsumerFeign80Application {

    public static void main(String[] args) {
        SpringApplication.run(MicroserviceStudentConsumerFeign80Application.class, args);
    }
}

StudentConsumerController

package com.tzj.microservicestudentconsumerfeign80.controller;

import com.tzj.microservicecommon.entity.Student;
import com.tzj.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();
    }
}

這樣就算我們生產者集羣有一個服務器宕機了，當Ribbon在輪迴的時候就會自動跳過它這個服務器了，其他的繼續運行

微服務調用Ribbon負載均衡及Feign的使用

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微服務調用Ribbon

Ribbon負載均衡

Feign簡介及應用

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