首先规划一个项目，功能需求如下图：
服务端分为账号和支付两个服务，客户端需要调用账号服务的登录接口和支付服务的查询余额接口，同时为了简化客户端处理，登录成功后账号服务会调用查询余额接口一同返回余额信息。
在技术选型上，尽可能使用Alibaba的组件，主要选择如下：
- 使用Nacos作为配置中心
- 使用Nacos作为注册中心，实现服务注册和发现
- 使用Feign作为服务调用组件
- 使用Ribbon实现服务调用的负载均衡
- 使用Sentinel实现限流和熔断, 并结合Nacos实现动态配置
- 使用Spring Cloud Gateway作为API网关
架构设计如下图：
一、动态配置
创建一个SpringBoot应用payment-service
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
application.yml
spring:
profiles:
active: dev
server:
port: 8082
sleep: 0
创建一个pojo类：Balance.java
public class Balance {
private int id;
private int diamond;
private int ticket;
private String message;
public Balance() {
}
public Balance(int id, int diamond, int ticket) {
this(id, diamond, ticket, "OK");
}
public Balance(int id, int diamond, int ticket, String message) {
this.id = id;
this.diamond = diamond;
this.ticket = ticket;
this.message = message;
}
//Setter/Getter略
}
创建Controller
@RestController
public class PaymentController {
@Value("${sleep:0}")
private int sleep;
final static Map<Integer, Balance> balanceMap = new HashMap() {{
put(1, new Balance(1, 10, 1000));
put(2, new Balance(2, 0, 10000));
put(3, new Balance(3, 100, 0));
}
};
@RequestMapping("/pay/balance")
public Balance getBalance(Integer id) {
System.out.println("request: /pay/balance?id=" + id + ", sleep: " + sleep);
if(sleep > 0) {
try {
Thread.sleep(sleep);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
if(id != null && balanceMap.containsKey(id)) {
return balanceMap.get(id);
}
return new Balance(0, 0, 0);
}
}
启动应用并测试
后台显示request: /pay/balance?id=1, sleep: 0
引入Nacos实现sleep参数动态配置
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Greenwich.SR1</spring-cloud.version>
<alibaba.version>0.9.0.RELEASE</alibaba.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
<version>${alibaba.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
添加bootstrap.yml，其中 server-addr即Nacos监听IP和端口
spring:
application:
name: payment-service
cloud:
nacos:
config:
server-addr: 127.0.0.1:8848
在Controller 上添加 @RefreshScope注解
@RestController
@RefreshScope
public class PaymentController {
打开Nacos管理后台创建配置payment-service-dev.properties，修改sleep=5000
点击发布
重启payment-service，可以看到启动窗口中显示
b.c.PropertySourceBootstrapConfiguration : Located property source: CompositePropertySource {name='NACOS', propertySources=[NacosPropertySource {name='payment-service-dev.properties'}, NacosPropertySource {name='payment-service.properties'}]}
刷新http://localhost:8082/pay/balance?id=1可以看到响应延迟5秒，同时控制台显示
request: /pay/balance?id=1, sleep: 5000
证明Nacos上的配置已经生效并覆盖了本地配置。
二、注册中心
1 添加注册依赖
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
<version>${alibaba.version}</version>
</dependency>
2 配置Nacos发现服务地址，修改后的bootstrap.yml如下
spring:
application:
name: payment-service
cloud:
nacos:
config:
server-addr: 127.0.0.1:8848
discovery:
server-addr: 127.0.0.1:8848
3 在启动类上添加注解@EnableDiscoveryClient
@SpringBootApplication
@EnableDiscoveryClient
public class PaymentServiceApplication {
控制台中输出
nacos registry, payment-service 192.168.75.1:8082 register finished
进入Nacos管理后台，在服务列表中已经可以看到payment-service服务(服务名为spring.application.name)
至此，服务Provider的工作完成，下面来写Consumer。
Consumer为账号服务，提供注册、登录等，其中部分接口需要调用payment-service服务获得余额信息合并后返回给客户端。
新建名称为account-service的SpringBoot应用，依赖、配置文件与payment-service基本相同，仅修改以下两项：
spring.application.name=account-service server.port=8081
业务代码：
User.java
public class User {
private int id;
private String name;
private Balance balance;
public User(int id, String name) {
this.id = id;
this.name = name;
}
public User() {
}
}
AccountController.java
@RestController
public class AccountController {
final static Map<Integer, User> userMap = new HashMap() {{
put(1, new User(1, "张三"));
put(2, new User(2, "李四"));
put(3, new User(3, "王五"));
}
};
@RequestMapping("/acc/user")
public User getUser(@RequestParam Integer id) {
if(id != null && userMap.containsKey(id)) {
User user = userMap.get(id);
return user;
}
return new User(0, "");
}
}
接下来添加调用payment-service服务的代码。添加相关依赖，如下：
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
在主类上开启Feign功能
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class AccountServiceApplication {
添加BalanceService接口
@FeignClient(name = "payment-service", fallback = BalanceServiceFallback.class)
public interface BalanceService {
@RequestMapping(value = "/pay/balance", method = RequestMethod.GET)
Balance getBalance(@RequestParam("id") Integer id);
}
添加BalanceServiceFallback.java
@Component
public class BalanceServiceFallback implements BalanceService {
@Override
public Balance getBalance(Integer id) {
return new Balance(0, 0, 0, "降级");
}
}
在account-service中添加依赖
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
<version>${alibaba.version}</version>
</dependency>
在bootstrap.yml中启用
feign:
sentinel:
enabled: true
修改sleep=5000并测试
降级成功。
代码地址：https://pan.baidu.com/s/1sMd7fJpQWUYnN4M67PBGEg
提取码：0gf0