User getUser(Long id);

List listUsers(UserQuery query);

void updateUser(User user);
}

# 定义数据模型
@Data
public class User implements Serializable {
private Long id;
private String name;
private Integer age;
private String email;
}

@Data
public class UserQuery implements Serializable {
private String name;
private Integer minAge;
private Integer maxAge;
}

@Autowired
private UserRepository userRepository;

@Override
public String sayHello(String name) {
return “Hello, ” + name + “! Welcome to Dubbo.”;
}

@Override
public User getUser(Long id) {
return userRepository.findById(id);
}

@Override
public List listUsers(UserQuery query) {
return userRepository.findByQuery(query);
}

@Override
public void updateUser(User user) {
userRepository.update(user);
}
}

# 启动类
@SpringBootApplication
@EnableDubbo
public class FgeduProviderApplication {
public static void main(String[] args) {
SpringApplication.run(FgeduProviderApplication.class, args);
}
}

@DubboReference(
version = “1.0.0”,
timeout = 5000,
retries = 2,
loadbalance = “roundrobin”,
mock = “com.fgedu.service.mock.FgeduServiceMock”
)
private FgeduService fgeduService;

@GetMapping(“/hello”)
public String hello(@RequestParam String name) {
return fgeduService.sayHello(name);
}

@GetMapping(“/user/{id}”)
public User getUser(@PathVariable Long id) {
return fgeduService.getUser(id);
}

@GetMapping(“/users”)
public List listUsers(UserQuery query) {
return fgeduService.listUsers(query);
}
}

# Mock降级实现
public class FgeduServiceMock implements FgeduService {
@Override
public String sayHello(String name) {
return “Mock: Hello, ” + name;
}

@Override
public User getUser(Long id) {
User user = new User();
user.setId(id);
user.setName(“Mock User”);
return user;
}
}

# Failfast Cluster
# 快速失败，只发起一次调用
@DubboService(cluster = “failfast”)

# Failsafe Cluster
# 失败安全，出现异常直接忽略
@DubboService(cluster = “failsafe”)

# Failback Cluster
# 失败自动恢复，后台记录失败请求定时重发
@DubboService(cluster = “failback”)

# Forking Cluster
# 并行调用多个服务器，一个成功即返回
@DubboService(cluster = “forking”, forks = 3)

# Broadcast Cluster
# 广播调用所有提供者，逐个调用
@DubboService(cluster = “broadcast”)

# RoundRobin LoadBalance
# 轮询，按公约后的权重设置轮询比率
@DubboService(loadbalance = “roundrobin”)

# LeastActive LoadBalance
# 最少活跃调用数，使慢的提供者收到更少请求
@DubboService(loadbalance = “leastactive”)

# ConsistentHash LoadBalance
# 一致性Hash，相同参数的请求总是发到同一提供者
@DubboService(loadbalance = “consistenthash”, arguments = {0})

# 配置示例
@DubboService(
version = “1.0.0”,
cluster = “failover”,
loadbalance = “roundrobin”,
retries = 2,
timeout = 5000
)
public class FgeduServiceImpl implements FgeduService {
// …
}

# 服务注册到指定注册中心
@DubboService(registry = {“nacos1”, “nacos2”})

# 服务订阅指定注册中心
@DubboReference(registry = “nacos1”)