Spring-Cloud-Eureka-Client

最新推荐文章于 2022-04-08 16:46:07 发布

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本文详细介绍了如何配置Spring Cloud Eureka客户端，包括一个仅提供服务的模块和一个同时提供服务并调用其他服务的模块。提供了POM配置、application.yml设置以及启动类代码。服务消费方式包括Feign和Ribbon，其中Feign通过接口调用，Ribbon使用@LoadBalanced的RestTemplate。还讨论了Ribbon的负载均衡策略，如轮询、随机等，并展示了如何自定义策略。

Spring-Cloud-Eureka-Client

1.Eureka-server就是一个注册中心，其他的Eureka-Client都是一个个的微服务，彼此间相互调用。
2.服务的提供仅仅需要引用spring-cloud-starter-netflix-eureka-client
3.服务的消费方式
1)：feign,一个通过本地接口的形式来进行调用服务的,其中Feign中默认引入了Ribbon，以接口的形式进行调用服务,看起来简洁,而且Feign中还可以增加熔断器,来进行服务的熔断和降级,防止服务调用中的服务的雪崩
需要引用spring-cloud-starter-netflix-eureka-client和spring-cloud-starter-openfeign，
spring-cloud-starter-netflix-eureka-client讲此模块注册到Eureka-server
spring-cloud-starter-openfeign,调用远程的服务
2):ribbon,一个基于Http端的负载均衡,通过在Configuration中配置RestTemplate来进行调用,可以自定义负载均衡的方式,需要在配置Bean:RestTemplate时加上@LoadBalanced

一个仅仅提供服务的模块（不调用其他的服务）

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-clould-Official</artifactId>
        <groupId>com.wx</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>Eureka-Client</artifactId>

    <dependencies>
        <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>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>

</project>

功效备注：

spring-cloud-starter-netflix-eureka-client

声明这是一个eureka客户端，要注册到eureka的服务之一

spring-boot-starter-web

使用@RestController等等注解，搭建MVC系统

spring-boot-starter-actuator

服务健康检查

application.yml


eureka:
  client:
    serviceUrl:
      defaultZone: http://192.168.88.1:8761/eureka/
    healthcheck:
      enabled: true
#   By default, the EurekaClient bean is refreshable, meaning the Eureka client properties can be changed and refreshed. When a refresh occurs clients will be unregistered from the Eureka server and there might be a brief moment of time where all instance of a given service are not available. One way to eliminate this from happening is to disable the ability to refresh Eureka clients. To do this set eureka.client.refresh.enable=false.
    refresh:
      enable: false
  instance:
    instanceId: ${spring.application.name}:${vcap.application.instance_id:${spring.application.instance_id:${random.value}}}
    leaseRenewalIntervalInSeconds: 30
server:
  port: 9001

spring:
  application:
    name: client01

EurekaCliApplication01.java（启动类）

package com.wx.client01;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;

@SpringBootApplication
//EnableEurekaClient可省略
//@EnableEurekaClient
public class EurekaCliApplication01 {

    public static void main(String[] args) {
        new SpringApplicationBuilder(EurekaCliApplication01.class).web(true).run(args);
    }
}

提供的服务

package com.wx.client01.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/hello")
public class HelloController {

    @RequestMapping("/sayhi")
    public String sayHi(@RequestParam(value = "name" ,defaultValue = "Lin") String name){
        return "Hi,"+name;
    }
}

一个既可以提供服务，又可以调用其他服务的模块

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-clould-Official</artifactId>
        <groupId>com.wx</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>Eureka-Client-02</artifactId>
    <dependencies>
        <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>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
    </dependencies>

</project>

application.yml

server:
  port: 9002

eureka:
  client:
    serviceUrl:
      defaultZone: http://192.168.88.1:8761/eureka/
    healthcheck:
      enabled: true
#   By default, the EurekaClient bean is refreshable, meaning the Eureka client properties can be changed and refreshed. When a refresh occurs clients will be unregistered from the Eureka server and there might be a brief moment of time where all instance of a given service are not available. One way to eliminate this from happening is to disable the ability to refresh Eureka clients. To do this set eureka.client.refresh.enable=false.
    refresh:
      enable: false
  instance:
    instanceId: ${spring.application.name}:${vcap.application.instance_id:${spring.application.instance_id:${random.value}}}
    leaseRenewalIntervalInSeconds: 30

spring:
  application:
    name: client01

启动类

package com.wx.client01;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
//EnableEurekaClient可省略
//@EnableEurekaClient
@EnableFeignClients
public class EurekaCliApplication02 {

    public static void main(String[] args) {
        new SpringApplicationBuilder(EurekaCliApplication02.class).web(true).run(args);
    }
}

MVC view

package com.wx.client01.controller;

import com.wx.client01.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
//import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/hello")
public class HelloController {
    @Autowired
    private HelloService helloService;

    @RequestMapping("/sayhi")
    public String sayHi(@RequestParam(value = "name" ,defaultValue = "opopopop") String name){

        return helloService.sayHi(name);
    }
}

feign 调用远程服务

package com.wx.client01.service;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

@Service
@FeignClient(value = "client01",name = "client01")
public interface HelloService {

    @RequestMapping(value = "/hello/sayhi")
    public String sayHi(@RequestParam("name") String name);

}

Ribbon调用

1.@LoadBalanced配置RestTemplate（没有@LoadBalanced会报错找不到主机）

package com.wx.client02.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 RestTemplateConfig {

    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }

}

2.调用

package com.wx.client02.controller;

import com.wx.client02.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/hello")
public class HelloController {

    @Autowired
    private RestTemplate restTemplate;

    @RequestMapping("/sayRest/{name}")
    public String sayRest(@PathVariable("name") String name){
        String serviceRest = restTemplate.getForObject("http://client01/hello/sayhi?name=" + name, String.class);
        return serviceRest;
    }
}

3.Ribbon 自带的负载均衡策略

RoundRobinRule：轮询。
RandomRule：随机。
AvailabilityFilteringRule：先过滤掉由于多次访问故障而处于断路器跳闸状态的服务，以及并发连接数超过阈值的服务，剩下的服务，使用轮询策略。
WeightedResponseTimeRule：根据平均响应时间计算所有服务的权重，响应越快的服务权重越高，越容易被选中。一开始启动时，统计信息不足的情况下，使用轮询。
RetryRule：先轮询，如果获取失败则在指定时间内重试，重新轮询可用的服务。
BestAvailableRule：先过滤掉由于多次访问故障而处于断路器跳闸状态的服务，然后选择一个并发量最小的服务。
ZoneAvoidanceRule：复合判断 server 所在区域的性能和 server 的可用性选择服务器

使用方法 new 相应的策略即可

package com.wx.client02.config;

import com.netflix.loadbalancer.RandomRule;
import com.netflix.loadbalancer.RoundRobinRule;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.SmartInitializingSingleton;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.client.loadbalancer.LoadBalancerAutoConfiguration;
import org.springframework.cloud.client.loadbalancer.RestTemplateCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

import java.util.List;

@Configuration
public class RestTemplateConfig {

    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
    @Bean
    public RoundRobinRule randomRule(){
        return new RoundRobinRule();
    }


}