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Spring Cloud 速查表

本文档提供 Spring Cloud 常用配置、组件和命令的快速参考。基于 Spring Cloud 2024.0.x (Moorgate) 版本。

版本对应关系​

Release TrainSpring Boot 版本JDK 版本
2024.0.x (Moorgate)3.4.x17+
2023.0.x (Leyton)3.3.x, 3.2.x17+
2022.0.x (Kilburn)3.0.x, 3.1.x17+

Maven 依赖管理​

BOM 依赖管理​

<properties>
    <spring-cloud.version>2024.0.0</spring-cloud.version>
</properties>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

常用依赖​

依赖说明
spring-cloud-starter-netflix-eureka-serverEureka 服务端
spring-cloud-starter-netflix-eureka-clientEureka 客户端
spring-cloud-starter-gatewayAPI 网关
spring-cloud-starter-loadbalancer负载均衡器
spring-cloud-starter-openfeign声明式 HTTP 客户端
spring-cloud-starter-config配置中心客户端
spring-cloud-starter-bootstrapBootstrap 上下文
spring-cloud-circuitbreaker-spring-retry断路器重试

服务注册与发现​

Eureka Server 搭建​

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
server:
  port: 8761

eureka:
  instance:
    hostname: localhost
  client:
    register-with-eureka: false
    fetch-registry: false
  server:
    enable-self-preservation: false
@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {
    public static void main(String[] args) {
        SpringApplication.run(EurekaServerApplication.class, args);
    }
}

Eureka Client 配置​

spring:
  application:
    name: user-service

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
    registry-fetch-interval-seconds: 30
  instance:
    prefer-ip-address: true
    lease-renewal-interval-in-seconds: 10
    lease-expiration-duration-in-seconds: 30
@SpringBootApplication
@EnableEurekaClient  // 或 @EnableDiscoveryClient
public class UserServiceApplication {
    public static void main(String[] args) {
        SpringApplication.run(UserServiceApplication.class, args);
    }
}

Nacos 服务注册​

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
spring:
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
        namespace: dev
        group: DEFAULT_GROUP

负载均衡​

Ribbon 配置​

@Configuration
public class RibbonConfig {
    @Bean
    public IRule ribbonRule() {
        return new RandomRule();  // 随机策略
    }
}

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

Spring Cloud Loadbalancer​

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-loadbalancer</artifactId>
</dependency>
spring:
  cloud:
    loadbalancer:
      configurations: default
      ribbon:
        enabled: false

使用服务名调用​

@Autowired
private RestTemplate restTemplate;

public User getUser(Long id) {
    String url = "http://user-service/user/" + id;
    return restTemplate.getForObject(url, User.class);
}

API 网关​

Spring Cloud Gateway 快速开始​

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>

静态路由配置​

server:
  port: 8080

spring:
  application:
    name: gateway-service
  cloud:
    gateway:
      routes:
        - id: user-service
          uri: http://localhost:8081
          predicates:
            - Path=/user/**
        - id: order-service
          uri: http://localhost:8082
          predicates:
            - Path=/order/**

动态路由（服务发现）​

spring:
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true
          lower-case-service-id: true
      routes:
        - id: user-service
          uri: lb://user-service
          predicates:
            - Path=/user/**

常用 Predicates​

predicates:
  - Path=/user/**          # 路径匹配
  - After=2024-01-01T00:00:00Z  # 时间之后
  - Before=2024-12-31T23:59:59Z # 时间之前
  - Between=2024-01-01T00:00:00Z,2024-12-31T23:59:59Z
  - Method=GET,POST        # 请求方法
  - Header=X-Request-Id, \d+  # 请求头
  - Query=username         # 查询参数
  - Cookie=token,.*        # Cookie
  - Host=**.example.com     # 主机名

常用 Filters​

filters:
  - StripPrefix=1           # 去掉前缀
  - AddRequestHeader=X-Request-Id,12345  # 添加请求头
  - RemoveRequestHeader=X-Token  # 移除请求头
  - AddResponseHeader=X-Response-Time,${executionTime}  # 添加响应头
  - PrefixPath=/api         # 添加前缀
  - RedirectTo=302,https://example.com  # 重定向
  - SetStatus=404           # 设置状态码
  - RequestSize=5000000     # 请求大小限制
  - Retry=3                 # 重试次数

熔断配置​

spring:
  cloud:
    gateway:
      routes:
        - id: user-service
          uri: lb://user-service
          filters:
            - name: CircuitBreaker
              args:
                name: slowCircuitBreaker
                fallbackUri: /fallback/user

服务调用​

OpenFeign 声明式客户端​

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
feign:
  client:
    config:
      default:
        connectTimeout: 5000
        readTimeout: 5000
  circuitbreaker:
    enabled: true
@FeignClient(name = "user-service", fallback = UserFallback.class)
public interface UserClient {
    @GetMapping("/user/{id}")
    User getUser(@PathVariable("id") Long id);
}

@Component
public class UserFallback implements UserClient {
    @Override
    public User getUser(Long id) {
        return new User();
    }
}
@SpringBootApplication
@EnableFeignClients
public class OrderApplication {
    public static void main(String[] args) {
        SpringApplication.run(OrderApplication.class, args);
    }
}

配置中心​

Spring Cloud Config​

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-config</artifactId>
</dependency>
spring:
  application:
    name: user-service
  cloud:
    config:
      uri: http://localhost:8888
      profile: dev
      label: master

Config Server​

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-config-server</artifactId>
</dependency>
server:
  port: 8888

spring:
  application:
    name: config-server
  cloud:
    config:
      server:
        git:
          uri: https://github.com/username/config-repo
          default-label: master
          username: xxx
          password: xxx
@SpringBootApplication
@EnableConfigServer
public class ConfigServerApplication {
    public static void main(String[] args) {
        SpringApplication.run(ConfigServerApplication.class, args);
    }
}

断路器​

Resilience4j 断路器​

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-circuitbreaker-resilience4j</artifactId>
</dependency>
resilience4j:
  circuitbreaker:
    instances:
      userService:
        registerHealthIndicator: true
        slidingWindowSize: 10
        minimumNumberOfCalls: 5
        permittedNumberOfCallsInHalfOpenState: 3
        automaticTransitionFromOpenToHalfOpenEnabled: true
        waitDurationInOpenState: 5s
        failureRateThreshold: 50
  timelimiter:
    instances:
      userService:
        timeoutDuration: 3s
@Service
public class UserService {
    @CircuitBreaker(name = "userService", fallbackMethod = "getUserFallback")
    public User getUser(Long id) {
        return restTemplate.getForObject("http://user-service/user/" + id, User.class);
    }

    private User getUserFallback(Long id, Exception e) {
        return new User();
    }
}

常用注解​

注解说明
@EnableEurekaServer启用 Eureka 服务端
@EnableEurekaClient启用 Eureka 客户端
@EnableDiscoveryClient启用服务发现客户端
@EnableFeignClients启用 Feign 客户端
@FeignClient声明 Feign 客户端
@EnableCircuitBreaker启用断路器
@CircuitBreaker断路器注解
@LoadBalanced负载均衡注解
@EnableConfigServer启用配置中心服务端

常见问题​

1. 无法连接到 Eureka​

eureka:
  instance:
    hostname: localhost
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
    register-with-eureka: true
    fetch-registry: true

2. 网关路由不生效​

spring:
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true  # 必须启用服务发现

3. Feign 调用超时​

feign:
  client:
    config:
      default:
        connectTimeout: 10000
        readTimeout: 10000

4. 负载均衡不生效​

确保使用 @LoadBalanced 注解修饰 RestTemplate，或使用 lb:// 前缀的 URI。

相关链接​