02-OpenFeign-微服务接入
1、依赖
由于是spring cloud项目,注意spring-boot、cloud、alibaba的版本兼容性
1.1、父级依赖
<properties>
<java.version>1.8</java.version>
<spring-boot.version>2.7.18</spring-boot.version>
<spring.cloud.version>2021.0.1</spring.cloud.version>
<spring.cloud.alibaba.version>2021.0.1.0</spring.cloud.alibaba.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-alibaba-dependencies</artifactId>
<version>${spring.cloud.alibaba.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring.cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<!-- SpringBoot 依赖配置 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>${spring-boot.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
1.2、子服务依赖
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<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</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-loadbalancer</artifactId>
</dependency>
</dependencies>
以下全部为调用方配置
2、配置项
启动项配置文件 需要在 bootstrap.yml添加如下内容:
server:
port: 8090
servlet:
context-path: /
spring:
application:
#nacos 注册时的服务名
name: open
profiles:
active: seata
cloud:
nacos:
discovery:
# nacos的服务地址,nacos-server中IP地址:端口号
server-addr: 192.168.20.113:8848
# 保持与下游服务一样的域
namespace: cedb1f46-d9ae-43b1-99db-39b245152543
group: DEFAULT_GROUP
openfeign的负载均衡策略:
- round-robin:轮询
- least-conne¢tion:最小连接数
- consistent-hashing:一致性HASH
或指定URL
@FeignClient(url = "127.0.0.1:9001",name = "async-feign",contextId = "identity")
2.2、添加注解@EnableFeignClients开启openFeign功能
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class OpenFeignConsumer9006Application{
public static void main(String[] args) {
SpringApplication.run(OpenFeignConsumer9006Application.class, args);
}
}
2.3、新建openFeign接口
value作为调用方服务名,可以用final static 常量代替
// 下游服务注册到nacos的服务名
@FeignClient(value = "user-service")
public interface OpenFeignUserService {
// 完整的调用地址,如果下游存在/contextPath 则需要补充
@GetMapping("/user/save")
String insert() ;
}
3、调用错误问题
1、503[Load balancer does not contain an instance for the service ...]
因为SpringCloud Feign在Hoxton.M2 RELEASED版本之后抛弃了Ribbon,
使用了spring-cloud-loadbalancer,所以我们这里还需要引入spring-cloud-loadbalancer的依赖,否则就会报错