【Spring Cloud 03】Ribbon客户端负载均衡
2021-02-24 10:51:17
新建一个微服务Module，名叫`bar-svc`
pom依赖
```xml
<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>
```
application.yml
```yaml
server:
port: 8002
spring:
application:
name: bar-service
eureka:
instance:
hostname: bar01
instance-id: ${eureka.instance.hostname}:${server.port}
prefer-ip-address: true
client:
register-with-eureka: true
fetch-registry: true
service-url:
defaultZone: http://your-eureka-server-ip:8761/eureka/
```
使用LoadBalanced增强RestTemplate，能解析服务名，并进行负载均衡
```java
package com.example;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
@RestController
public class BarApplication {
public static void main(String[] args) {
SpringApplication.run(BarApplication.class, args);
}
// 对RestTemplate进行增强
@Bean
@LoadBalanced
public RestTemplate restTemplate() {
return new RestTemplate();
}
@Autowired
RestTemplate restTemplate;
@GetMapping("/demo")
public String demo() {
// 调用 FOO-SERVICE 服务的 /version, serviceId不区分大小写,不要端口号
ResponseEntity<String> res = restTemplate.getForEntity("http://FOO-SERVICE/version", String.class);
return "[bar-service] foo.version: " + res.getBody();
}
}
```