Java服务治理
AI生成声明: 本文档由AI辅助生成，旨在提供Java服务治理技术的完整指南。
🎯 概述
服务治理是微服务架构中的重要组成部分，包括限流、熔断、降级、负载均衡等功能，保证系统的稳定性和可用性。
📚 核心功能
限流 (Rate Limiting)
限流是控制服务请求速率，防止系统过载。
算法
- 固定窗口: 固定时间窗口内的请求数限制
- 滑动窗口: 滑动时间窗口内的请求数限制
- 令牌桶: 令牌桶算法
- 漏桶: 漏桶算法
Sentinel限流
java
// Sentinel配置
@Configuration
public class SentinelConfig {
@PostConstruct
public void init() {
// 定义限流规则
List<FlowRule> rules = new ArrayList<>();
FlowRule rule = new FlowRule();
rule.setResource("getUser");
rule.setGrade(RuleConstant.FLOW_GRADE_QPS);
rule.setCount(100); // QPS限制为100
rules.add(rule);
FlowRuleManager.loadRules(rules);
}
}
// 使用
@Service
public class UserService {
@SentinelResource(value = "getUser", blockHandler = "handleBlock")
public User getUser(Long id) {
return userRepository.findById(id);
}
public User handleBlock(Long id, BlockException ex) {
// 限流降级处理
return new User();
}
}Resilience4j限流
java
// Resilience4j限流
@Configuration
public class Resilience4jConfig {
@Bean
public RateLimiter userServiceRateLimiter() {
return RateLimiter.of("userService",
RateLimiterConfig.custom()
.limitRefreshPeriod(Duration.ofSeconds(1))
.limitForPeriod(100)
.timeoutDuration(Duration.ofMillis(100))
.build());
}
}
// 使用
@Service
public class UserService {
@Autowired
private RateLimiter rateLimiter;
public User getUser(Long id) {
return rateLimiter.executeSupplier(() -> {
return userRepository.findById(id);
});
}
}熔断 (Circuit Breaker)
熔断是当服务异常率过高时，快速失败，避免级联故障。
Hystrix熔断
java
// Hystrix命令
@Component
public class UserServiceCommand extends HystrixCommand<User> {
private Long userId;
public UserServiceCommand(Long userId) {
super(HystrixCommandGroupKey.Factory.asKey("UserGroup"),
HystrixCommandProperties.Setter()
.withCircuitBreakerRequestVolumeThreshold(10)
.withCircuitBreakerErrorThresholdPercentage(50)
.withCircuitBreakerSleepWindowInMilliseconds(5000));
this.userId = userId;
}
@Override
protected User run() throws Exception {
return userService.getUser(userId);
}
@Override
protected User getFallback() {
return new User(); // 熔断降级
}
}Resilience4j熔断
java
// Resilience4j熔断
@Configuration
public class Resilience4jConfig {
@Bean
public CircuitBreaker userServiceCircuitBreaker() {
return CircuitBreaker.of("userService",
CircuitBreakerConfig.custom()
.failureRateThreshold(50)
.waitDurationInOpenState(Duration.ofMillis(1000))
.slidingWindowSize(10)
.build());
}
}
// 使用
@Service
public class UserService {
@Autowired
private CircuitBreaker circuitBreaker;
public User getUser(Long id) {
return circuitBreaker.executeSupplier(() -> {
return userRepository.findById(id);
});
}
}降级 (Degradation)
降级是在系统压力过大时，暂时关闭非核心功能，保证核心功能可用。
服务降级
java
// 降级策略
@Service
public class UserService {
@HystrixCommand(fallbackMethod = "getUserFallback")
public User getUser(Long id) {
return userRepository.findById(id);
}
public User getUserFallback(Long id) {
// 降级逻辑：返回默认用户
return User.defaultUser();
}
@HystrixCommand(fallbackMethod = "getUserDetailFallback")
public UserDetail getUserDetail(Long id) {
return userDetailRepository.findById(id);
}
public UserDetail getUserDetailFallback(Long id) {
// 降级逻辑：返回简化信息
return UserDetail.simple(id);
}
}功能降级
java
// 功能开关
@Component
public class FeatureToggle {
@Value("${feature.detail.enabled:true}")
private boolean detailEnabled;
public boolean isDetailEnabled() {
return detailEnabled;
}
}
// 使用
@Service
public class UserService {
@Autowired
private FeatureToggle featureToggle;
public UserInfo getUserInfo(Long id) {
User user = getUser(id);
if (featureToggle.isDetailEnabled()) {
UserDetail detail = getUserDetail(id);
return UserInfo.withDetail(user, detail);
} else {
return UserInfo.simple(user);
}
}
}负载均衡
负载均衡是将请求分发到多个服务实例。
Ribbon负载均衡
java
// Ribbon配置
@Configuration
public class RibbonConfig {
@Bean
public IRule ribbonRule() {
return new RoundRobinRule(); // 轮询
// return new RandomRule(); // 随机
// return new WeightedResponseTimeRule(); // 加权响应时间
}
}
// 使用
@Service
public class UserService {
@Autowired
@LoadBalanced
private RestTemplate restTemplate;
public User getUser(Long id) {
return restTemplate.getForObject(
"http://user-service/users/{id}",
User.class,
id
);
}
}Spring Cloud LoadBalancer
java
// LoadBalancer配置
@Configuration
public class LoadBalancerConfig {
@Bean
public ReactorLoadBalancer<ServiceInstance> randomLoadBalancer(
Environment environment,
LoadBalancerClientFactory loadBalancerClientFactory) {
String name = environment.getProperty(LoadBalancerClientFactory.PROPERTY_NAME);
return new RandomLoadBalancer(
loadBalancerClientFactory.getLazyProvider(name, ServiceInstanceListSupplier.class),
name);
}
}🔧 综合方案
Sentinel完整示例
java
// Sentinel完整配置
@Configuration
public class SentinelConfig {
@PostConstruct
public void init() {
// 限流规则
initFlowRules();
// 熔断规则
initCircuitBreakerRules();
// 降级规则
initDegradeRules();
}
private void initFlowRules() {
List<FlowRule> rules = new ArrayList<>();
FlowRule rule = new FlowRule();
rule.setResource("getUser");
rule.setGrade(RuleConstant.FLOW_GRADE_QPS);
rule.setCount(100);
rules.add(rule);
FlowRuleManager.loadRules(rules);
}
private void initCircuitBreakerRules() {
List<CircuitBreakerRule> rules = new ArrayList<>();
CircuitBreakerRule rule = new CircuitBreakerRule();
rule.setResource("getUser");
rule.setGrade(CircuitBreakerStrategy.ERROR_RATIO);
rule.setCount(0.5); // 错误率50%
rule.setTimeWindow(10); // 时间窗口10秒
rules.add(rule);
CircuitBreakerRuleManager.loadRules(rules);
}
private void initDegradeRules() {
List<DegradeRule> rules = new ArrayList<>();
DegradeRule rule = new DegradeRule();
rule.setResource("getUser");
rule.setGrade(RuleConstant.DEGRADE_GRADE_RT);
rule.setCount(1000); // RT阈值1000ms
rule.setTimeWindow(10); // 时间窗口10秒
rules.add(rule);
DegradeRuleManager.loadRules(rules);
}
}💡 最佳实践
- 限流策略: 根据系统容量设置合理的限流阈值
- 熔断配置: 设置合理的熔断阈值和时间窗口
- 降级方案: 设计完善的降级策略
- 监控告警: 监控服务治理指标
- 动态调整: 支持动态调整治理规则
📖 学习资源
💡 下一步
- Spring Cloud - Spring Cloud微服务生态
- Apache Dubbo - Dubbo RPC框架
- 分布式事务解决方案 - Seata、LCN等
最后更新时间: 2025-01-20