SpringCloud的服务注册中心有Eureka、Zookeeper、Consul和Nacos
Eureka(AP)在SpringBoot1.x中比较合适,但是现在是SpringBoot2.x,而且Eureka已经停止更新了,就是不建议在使用了
Zookeeper(CP)是dubbo的注册中心,曾经的Eureka都凉了,万一我用别的注册中心又凉了怎么办,不如用zookeeper
Consul(CP)是Go语言开发的,而Java开发者可能会对不同的语言有偏见。
Nacos是比较推荐的服务注册中心。
Consul下载地址 Downloads | Consul by HashiCorp
下载完解压后是一个consul.exe
查看consul的版本(不用配置环境变量)
consul --version
启动consul
consul agent -dev
在浏览器输入
http://localhost:8500/
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-consul-discovery</artifactId>
<version>2.2.1.RELEASE</version>
</dependency>
代码下载
https://github.com/cbeann/share/tree/master/springcloud-Consul-demo
添加依赖
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-consul-discovery</artifactId>
<version>2.2.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
修改application.yml文件
server:
port: 8001
# 服务别名--consul注册中心名称
spring:
application:
name: provider-8001
cloud:
consul:
host: localhost
port: 8500
discovery:
service-name: ${spring.application.name}
修改主启动类
@EnableDiscoveryClient
编写controller
@RestController
public class HelloController {
@Value("${server.port}")
private String serverPort;
@RequestMapping("/provider/consul")
public String paymentConsul() {
return "springCloud with consul: " + serverPort + "\t" + UUID.randomUUID().toString();
}
}
启动并且自测
http://localhost:8001/provider/consul
添加依赖
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-consul-discovery</artifactId>
<version>2.2.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
修改application.yml文件
server:
port: 80
# 服务别名---consul注册中心名称
spring:
application:
name: consumer-80
cloud:
consul:
host: localhost
port: 8500
discovery:
service-name: ${spring.application.name}
修改主启动类
@EnableDiscoveryClient
添加RestTemplate配置类
@Configuration
public class ApplicationContextConfig {
@Bean
@LoadBalanced
public RestTemplate getRestTemplate(){
return new RestTemplate();
}
}
编写controller
@RestController
public class HelloController {
//调用服务的名称provider-8001
private static final String INVOKE_URL = "http://provider-8001";
@Autowired
private RestTemplate restTemplate;
@GetMapping(value = "/consumer/consul")
public String paymentInfo(){
String result = restTemplate.getForObject(INVOKE_URL + "/provider/consul", String.class);
return result;
}
}
启动自测
http://localhost/consumer/consul
如下图所示,正常情况是绿色对勾是2,这样访问会报 No instances available for provider
解决办法
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>