第212集Nginx代理Tomcat负载均衡架构实战：反向代理、会话保持、故障转移的企业级解决方案

/**
 * Redis会话管理器
 * 实现分布式会话管理
 */
@Component
public class RedisSessionManager {
    private final RedisTemplate<String, Object> redisTemplate;
    private final String sessionPrefix = "session:";
    private final int sessionTimeout = 1800; // 30分钟
    
    public RedisSessionManager(RedisTemplate<String, Object> redisTemplate) {
        this.redisTemplate = redisTemplate;
    }
    
    /**
     * 创建会话
     */
    public String createSession(String userId, Map<String, Object> attributes) {
        String sessionId = UUID.randomUUID().toString();
        String sessionKey = sessionPrefix + sessionId;
        
        // 存储会话数据
        Map<String, Object> sessionData = new HashMap<>();
        sessionData.put("userId", userId);
        sessionData.put("createTime", System.currentTimeMillis());
        sessionData.put("lastAccessTime", System.currentTimeMillis());
        sessionData.putAll(attributes);
        
        redisTemplate.opsForHash().putAll(sessionKey, sessionData);
        redisTemplate.expire(sessionKey, Duration.ofSeconds(sessionTimeout));
        
        return sessionId;
    }
    
    /**
     * 获取会话
     */
    public Map<String, Object> getSession(String sessionId) {
        String sessionKey = sessionPrefix + sessionId;
        Map<Object, Object> sessionData = redisTemplate.opsForHash().entries(sessionKey);
        
        if (sessionData.isEmpty()) {
            return null;
        }
        
        // 更新最后访问时间
        redisTemplate.opsForHash().put(sessionKey, "lastAccessTime", System.currentTimeMillis());
        redisTemplate.expire(sessionKey, Duration.ofSeconds(sessionTimeout));
        
        // 转换类型
        Map<String, Object> result = new HashMap<>();
        sessionData.forEach((k, v) -> result.put(k.toString(), v));
        
        return result;
    }
    
    /**
     * 更新会话属性
     */
    public void updateSessionAttribute(String sessionId, String key, Object value) {
        String sessionKey = sessionPrefix + sessionId;
        redisTemplate.opsForHash().put(sessionKey, key, value);
        redisTemplate.expire(sessionKey, Duration.ofSeconds(sessionTimeout));
    }
    
    /**
     * 删除会话
     */
    public void deleteSession(String sessionId) {
        String sessionKey = sessionPrefix + sessionId;
        redisTemplate.delete(sessionKey);
    }
    
    /**
     * 检查会话是否存在
     */
    public boolean sessionExists(String sessionId) {
        String sessionKey = sessionPrefix + sessionId;
        return redisTemplate.hasKey(sessionKey);
    }
    
    /**
     * 获取会话过期时间
     */
    public long getSessionTTL(String sessionId) {
        String sessionKey = sessionPrefix + sessionId;
        return redisTemplate.getExpire(sessionKey);
    }
}

/**
 * 会话拦截器
 */
@Component
public class SessionInterceptor implements HandlerInterceptor {
    private final RedisSessionManager sessionManager;
    
    public SessionInterceptor(RedisSessionManager sessionManager) {
        this.sessionManager = sessionManager;
    }
    
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        String sessionId = getSessionId(request);
        
        if (sessionId != null) {
            Map<String, Object> session = sessionManager.getSession(sessionId);
            if (session != null) {
                // 将会话数据存储到请求属性中
                request.setAttribute("session", session);
                return true;
            } else {
                // 会话不存在，清除Cookie
                clearSessionCookie(response);
            }
        }
        
        return true;
    }
    
    private String getSessionId(HttpServletRequest request) {
        Cookie[] cookies = request.getCookies();
        if (cookies != null) {
            for (Cookie cookie : cookies) {
                if ("JSESSIONID".equals(cookie.getName())) {
                    return cookie.getValue();
                }
            }
        }
        return null;
    }
    
    private void clearSessionCookie(HttpServletResponse response) {
        Cookie cookie = new Cookie("JSESSIONID", "");
        cookie.setMaxAge(0);
        cookie.setPath("/");
        response.addCookie(cookie);
    }
}

/**
 * 会话同步管理器
 * 实现多Tomcat实例间的会话同步
 */
@Component
public class SessionSyncManager {
    private final RedisTemplate<String, Object> redisTemplate;
    private final String syncChannel = "session_sync";
    private final RedisMessageListenerContainer messageContainer;
    
    public SessionSyncManager(RedisTemplate<String, Object> redisTemplate,
                             RedisMessageListenerContainer messageContainer) {
        this.redisTemplate = redisTemplate;
        this.messageContainer = messageContainer;
        
        // 订阅会话同步消息
        messageContainer.addMessageListener(new SessionSyncListener(), new PatternTopic(syncChannel + ":*"));
    }
    
    /**
     * 同步会话到其他实例
     */
    public void syncSession(String sessionId, String action, Map<String, Object> sessionData) {
        SessionSyncMessage message = new SessionSyncMessage();
        message.setSessionId(sessionId);
        message.setAction(action);
        message.setSessionData(sessionData);
        message.setTimestamp(System.currentTimeMillis());
        message.setInstanceId(getInstanceId());
        
        // 发布同步消息
        String channel = syncChannel + ":" + action;
        redisTemplate.convertAndSend(channel, message);
    }
    
    /**
     * 会话同步消息监听器
     */
    private class SessionSyncListener implements MessageListener {
        @Override
        public void onMessage(Message message, byte[] pattern) {
            try {
                SessionSyncMessage syncMessage = (SessionSyncMessage) message.getBody();
                
                // 忽略自己发送的消息
                if (getInstanceId().equals(syncMessage.getInstanceId())) {
                    return;
                }
                
                // 处理同步消息
                handleSessionSync(syncMessage);
                
            } catch (Exception e) {
                log.error("处理会话同步消息失败", e);
            }
        }
    }
    
    /**
     * 处理会话同步
     */
    private void handleSessionSync(SessionSyncMessage message) {
        String action = message.getAction();
        String sessionId = message.getSessionId();
        
        switch (action) {
            case "create":
            case "update":
                // 更新本地会话缓存
                updateLocalSession(sessionId, message.getSessionData());
                break;
            case "delete":
                // 删除本地会话缓存
                removeLocalSession(sessionId);
                break;
            case "expire":
                // 标记会话过期
                markSessionExpired(sessionId);
                break;
        }
    }
    
    private void updateLocalSession(String sessionId, Map<String, Object> sessionData) {
        // 更新本地会话缓存
    }
    
    private void removeLocalSession(String sessionId) {
        // 删除本地会话缓存
    }
    
    private void markSessionExpired(String sessionId) {
        // 标记会话过期
    }
    
    private String getInstanceId() {
        return InetAddress.getLocalHost().getHostName() + ":" + 
               ManagementFactory.getRuntimeMXBean().getName();
    }
}

/**
 * 会话同步消息
 */
class SessionSyncMessage {
    private String sessionId;
    private String action;
    private Map<String, Object> sessionData;
    private long timestamp;
    private String instanceId;
    
    // getters and setters
    public String getSessionId() { return sessionId; }
    public void setSessionId(String sessionId) { this.sessionId = sessionId; }
    public String getAction() { return action; }
    public void setAction(String action) { this.action = action; }
    public Map<String, Object> getSessionData() { return sessionData; }
    public void setSessionData(Map<String, Object> sessionData) { this.sessionData = sessionData; }
    public long getTimestamp() { return timestamp; }
    public void setTimestamp(long timestamp) { this.timestamp = timestamp; }
    public String getInstanceId() { return instanceId; }
    public void setInstanceId(String instanceId) { this.instanceId = instanceId; }
}

/**
 * Tomcat健康检查控制器
 * 提供应用健康状态检查
 */
@RestController
@RequestMapping("/health")
public class HealthCheckController {
    private final HealthIndicator healthIndicator;
    private final DatabaseHealthChecker databaseHealthChecker;
    private final RedisHealthChecker redisHealthChecker;
    
    public HealthCheckController(HealthIndicator healthIndicator,
                                DatabaseHealthChecker databaseHealthChecker,
                                RedisHealthChecker redisHealthChecker) {
        this.healthIndicator = healthIndicator;
        this.databaseHealthChecker = databaseHealthChecker;
        this.redisHealthChecker = redisHealthChecker;
    }
    
    /**
     * 基础健康检查
     */
    @GetMapping
    public ResponseEntity<Map<String, Object>> health() {
        Map<String, Object> health = new HashMap<>();
        health.put("status", "UP");
        health.put("timestamp", System.currentTimeMillis());
        health.put("instance", getInstanceInfo());
        
        return ResponseEntity.ok(health);
    }
    
    /**
     * 详细健康检查
     */
    @GetMapping("/detailed")
    public ResponseEntity<Map<String, Object>> detailedHealth() {
        Map<String, Object> health = new HashMap<>();
        Map<String, Object> checks = new HashMap<>();
        
        // 检查数据库
        HealthStatus dbStatus = databaseHealthChecker.check();
        checks.put("database", dbStatus);
        
        // 检查Redis
        HealthStatus redisStatus = redisHealthChecker.check();
        checks.put("redis", redisStatus);
        
        // 检查JVM
        HealthStatus jvmStatus = healthIndicator.getJvmHealth();
        checks.put("jvm", jvmStatus);
        
        // 检查磁盘空间
        HealthStatus diskStatus = healthIndicator.getDiskHealth();
        checks.put("disk", diskStatus);
        
        health.put("status", determineOverallStatus(checks));
        health.put("checks", checks);
        health.put("timestamp", System.currentTimeMillis());
        
        return ResponseEntity.ok(health);
    }
    
    /**
     * 就绪检查
     */
    @GetMapping("/ready")
    public ResponseEntity<Map<String, Object>> readiness() {
        Map<String, Object> readiness = new HashMap<>();
        
        // 检查关键组件
        boolean dbReady = databaseHealthChecker.isReady();
        boolean redisReady = redisHealthChecker.isReady();
        
        if (dbReady && redisReady) {
            readiness.put("status", "READY");
            return ResponseEntity.ok(readiness);
        } else {
            readiness.put("status", "NOT_READY");
            readiness.put("reason", "Dependencies not ready");
            return ResponseEntity.status(HttpStatus.SERVICE_UNAVAILABLE).body(readiness);
        }
    }
    
    /**
     * 存活检查
     */
    @GetMapping("/live")
    public ResponseEntity<Map<String, Object>> liveness() {
        Map<String, Object> liveness = new HashMap<>();
        liveness.put("status", "ALIVE");
        liveness.put("timestamp", System.currentTimeMillis());
        
        return ResponseEntity.ok(liveness);
    }
    
    private String determineOverallStatus(Map<String, Object> checks) {
        for (Object check : checks.values()) {
            if (check instanceof HealthStatus) {
                HealthStatus status = (HealthStatus) check;
                if (!"UP".equals(status.getStatus())) {
                    return "DOWN";
                }
            }
        }
        return "UP";
    }
    
    private Map<String, Object> getInstanceInfo() {
        Map<String, Object> info = new HashMap<>();
        info.put("hostname", getHostname());
        info.put("port", getServerPort());
        info.put("pid", getProcessId());
        return info;
    }
    
    private String getHostname() {
        try {
            return InetAddress.getLocalHost().getHostName();
        } catch (Exception e) {
            return "unknown";
        }
    }
    
    private int getServerPort() {
        return 8080; // 从配置中获取
    }
    
    private long getProcessId() {
        return ProcessHandle.current().pid();
    }
}

/**
 * 健康状态
 */
class HealthStatus {
    private String status;
    private Map<String, Object> details;
    private long timestamp;
    
    public HealthStatus(String status) {
        this.status = status;
        this.details = new HashMap<>();
        this.timestamp = System.currentTimeMillis();
    }
    
    public HealthStatus(String status, Map<String, Object> details) {
        this.status = status;
        this.details = details != null ? details : new HashMap<>();
        this.timestamp = System.currentTimeMillis();
    }
    
    // getters and setters
    public String getStatus() { return status; }
    public void setStatus(String status) { this.status = status; }
    public Map<String, Object> getDetails() { return details; }
    public void setDetails(Map<String, Object> details) { this.details = details; }
    public long getTimestamp() { return timestamp; }
    public void setTimestamp(long timestamp) { this.timestamp = timestamp; }
}

/**
 * 数据库健康检查器
 */
@Component
public class DatabaseHealthChecker {
    private final DataSource dataSource;
    
    public DatabaseHealthChecker(DataSource dataSource) {
        this.dataSource = dataSource;
    }
    
    public HealthStatus check() {
        try (Connection connection = dataSource.getConnection()) {
            // 执行简单查询
            try (PreparedStatement stmt = connection.prepareStatement("SELECT 1")) {
                try (ResultSet rs = stmt.executeQuery()) {
                    if (rs.next()) {
                        Map<String, Object> details = new HashMap<>();
                        details.put("responseTime", System.currentTimeMillis());
                        return new HealthStatus("UP", details);
                    }
                }
            }
        } catch (Exception e) {
            Map<String, Object> details = new HashMap<>();
            details.put("error", e.getMessage());
            return new HealthStatus("DOWN", details);
        }
        
        return new HealthStatus("DOWN");
    }
    
    public boolean isReady() {
        return "UP".equals(check().getStatus());
    }
}

/**
 * Redis健康检查器
 */
@Component
public class RedisHealthChecker {
    private final RedisTemplate<String, Object> redisTemplate;
    
    public RedisHealthChecker(RedisTemplate<String, Object> redisTemplate) {
        this.redisTemplate = redisTemplate;
    }
    
    public HealthStatus check() {
        try {
            long startTime = System.currentTimeMillis();
            String result = redisTemplate.opsForValue().get("health:check").toString();
            long responseTime = System.currentTimeMillis() - startTime;
            
            Map<String, Object> details = new HashMap<>();
            details.put("responseTime", responseTime);
            details.put("result", result);
            
            return new HealthStatus("UP", details);
        } catch (Exception e) {
            Map<String, Object> details = new HashMap<>();
            details.put("error", e.getMessage());
            return new HealthStatus("DOWN", details);
        }
    }
    
    public boolean isReady() {
        return "UP".equals(check().getStatus());
    }
}

/**
 * 健康指示器
 */
@Component
public class HealthIndicator {
    
    public HealthStatus getJvmHealth() {
        Runtime runtime = Runtime.getRuntime();
        long totalMemory = runtime.totalMemory();
        long freeMemory = runtime.freeMemory();
        long usedMemory = totalMemory - freeMemory;
        long maxMemory = runtime.maxMemory();
        
        double memoryUsage = (double) usedMemory / maxMemory;
        
        Map<String, Object> details = new HashMap<>();
        details.put("totalMemory", totalMemory);
        details.put("usedMemory", usedMemory);
        details.put("freeMemory", freeMemory);
        details.put("maxMemory", maxMemory);
        details.put("memoryUsage", memoryUsage);
        
        String status = memoryUsage > 0.9 ? "DOWN" : "UP";
        return new HealthStatus(status, details);
    }
    
    public HealthStatus getDiskHealth() {
        File root = new File("/");
        long totalSpace = root.getTotalSpace();
        long freeSpace = root.getFreeSpace();
        long usedSpace = totalSpace - freeSpace;
        
        double diskUsage = (double) usedSpace / totalSpace;
        
        Map<String, Object> details = new HashMap<>();
        details.put("totalSpace", totalSpace);
        details.put("usedSpace", usedSpace);
        details.put("freeSpace", freeSpace);
        details.put("diskUsage", diskUsage);
        
        String status = diskUsage > 0.9 ? "DOWN" : "UP";
        return new HealthStatus(status, details);
    }
}

/**
 * 企业级Web负载均衡管理器
 * 集成Nginx和Tomcat的完整解决方案
 */
@Component
public class EnterpriseWebLoadBalancer {
    private final NginxConfigManager nginxConfigManager;
    private final TomcatClusterManager tomcatClusterManager;
    private final SessionManager sessionManager;
    private final HealthCheckManager healthCheckManager;
    private final MonitoringManager monitoringManager;
    
    public EnterpriseWebLoadBalancer(NginxConfigManager nginxConfigManager,
                                   TomcatClusterManager tomcatClusterManager,
                                   SessionManager sessionManager,
                                   HealthCheckManager healthCheckManager,
                                   MonitoringManager monitoringManager) {
        this.nginxConfigManager = nginxConfigManager;
        this.tomcatClusterManager = tomcatClusterManager;
        this.sessionManager = sessionManager;
        this.healthCheckManager = healthCheckManager;
        this.monitoringManager = monitoringManager;
        
        // 初始化架构
        initializeArchitecture();
    }
    
    /**
     * 初始化架构
     */
    private void initializeArchitecture() {
        // 启动健康检查
        healthCheckManager.startHealthChecks();
        
        // 启动监控
        monitoringManager.startMonitoring();
        
        // 配置负载均衡策略
        configureLoadBalancingStrategies();
        
        // 配置会话管理
        configureSessionManagement();
    }
    
    /**
     * 配置负载均衡策略
     */
    private void configureLoadBalancingStrategies() {
        Map<String, LoadBalancingStrategy> strategies = new HashMap<>();
        strategies.put("round_robin", new RoundRobinStrategy());
        strategies.put("least_conn", new LeastConnectionStrategy());
        strategies.put("ip_hash", new IpHashStrategy());
        strategies.put("weighted", new WeightedStrategy());
        
        // 应用策略
        for (LoadBalancingStrategy strategy : strategies.values()) {
            strategy.configure();
        }
    }
    
    /**
     * 配置会话管理
     */
    private void configureSessionManagement() {
        SessionConfiguration config = new SessionConfiguration();
        config.setSessionTimeout(1800); // 30分钟
        config.setSessionStore("redis");
        config.setSessionSync(true);
        config.setStickySession(false);
        
        sessionManager.configure(config);
    }
    
    /**
     * 添加Tomcat实例
     */
    public void addTomcatInstance(TomcatInstance instance) {
        tomcatClusterManager.addInstance(instance);
        nginxConfigManager.addUpstreamServer(instance);
        
        // 启动健康检查
        healthCheckManager.addHealthCheck(instance);
        
        // 重新加载Nginx配置
        nginxConfigManager.reloadConfiguration();
    }
    
    /**
     * 移除Tomcat实例
     */
    public void removeTomcatInstance(String instanceId) {
        tomcatClusterManager.removeInstance(instanceId);
        nginxConfigManager.removeUpstreamServer(instanceId);
        
        // 停止健康检查
        healthCheckManager.removeHealthCheck(instanceId);
        
        // 重新加载Nginx配置
        nginxConfigManager.reloadConfiguration();
    }
    
    /**
     * 更新负载均衡策略
     */
    public void updateLoadBalancingStrategy(String strategy) {
        nginxConfigManager.updateLoadBalancingStrategy(strategy);
        nginxConfigManager.reloadConfiguration();
    }
    
    /**
     * 获取负载均衡状态
     */
    public LoadBalancerStatus getStatus() {
        LoadBalancerStatus status = new LoadBalancerStatus();
        
        // 收集Tomcat实例状态
        status.setTomcatInstances(tomcatClusterManager.getInstances());
        
        // 收集Nginx状态
        status.setNginxStatus(nginxConfigManager.getStatus());
        
        // 收集健康检查状态
        status.setHealthStatus(healthCheckManager.getStatus());
        
        // 收集性能指标
        status.setPerformanceMetrics(monitoringManager.getMetrics());
        
        return status;
    }
    
    /**
     * 执行故障转移
     */
    public void performFailover(String failedInstanceId) {
        // 标记实例为故障
        tomcatClusterManager.markInstanceFailed(failedInstanceId);
        
        // 从Nginx配置中移除故障实例
        nginxConfigManager.removeUpstreamServer(failedInstanceId);
        
        // 重新加载Nginx配置
        nginxConfigManager.reloadConfiguration();
        
        // 记录故障转移事件
        monitoringManager.recordFailoverEvent(failedInstanceId);
    }
    
    /**
     * 执行故障恢复
     */
    public void performFailover(String instanceId) {
        // 验证实例健康状态
        if (healthCheckManager.isHealthy(instanceId)) {
            // 恢复实例
            tomcatClusterManager.markInstanceHealthy(instanceId);
            
            // 重新添加到Nginx配置
            TomcatInstance instance = tomcatClusterManager.getInstance(instanceId);
            nginxConfigManager.addUpstreamServer(instance);
            
            // 重新加载Nginx配置
            nginxConfigManager.reloadConfiguration();
            
            // 记录恢复事件
            monitoringManager.recordRecoveryEvent(instanceId);
        }
    }
}

/**
 * Tomcat实例
 */
class TomcatInstance {
    private String id;
    private String host;
    private int port;
    private int weight;
    private String status;
    private Map<String, Object> metadata;
    
    public TomcatInstance(String id, String host, int port) {
        this.id = id;
        this.host = host;
        this.port = port;
        this.weight = 1;
        this.status = "UP";
        this.metadata = new HashMap<>();
    }
    
    // getters and setters
    public String getId() { return id; }
    public void setId(String id) { this.id = id; }
    public String getHost() { return host; }
    public void setHost(String host) { this.host = host; }
    public int getPort() { return port; }
    public void setPort(int port) { this.port = port; }
    public int getWeight() { return weight; }
    public void setWeight(int weight) { this.weight = weight; }
    public String getStatus() { return status; }
    public void setStatus(String status) { this.status = status; }
    public Map<String, Object> getMetadata() { return metadata; }
    public void setMetadata(Map<String, Object> metadata) { this.metadata = metadata; }
}

/**
 * 负载均衡状态
 */
class LoadBalancerStatus {
    private List<TomcatInstance> tomcatInstances;
    private NginxStatus nginxStatus;
    private HealthStatus healthStatus;
    private PerformanceMetrics performanceMetrics;
    
    // getters and setters
    public List<TomcatInstance> getTomcatInstances() { return tomcatInstances; }
    public void setTomcatInstances(List<TomcatInstance> tomcatInstances) { this.tomcatInstances = tomcatInstances; }
    public NginxStatus getNginxStatus() { return nginxStatus; }
    public void setNginxStatus(NginxStatus nginxStatus) { this.nginxStatus = nginxStatus; }
    public HealthStatus getHealthStatus() { return healthStatus; }
    public void setHealthStatus(HealthStatus healthStatus) { this.healthStatus = healthStatus; }
    public PerformanceMetrics getPerformanceMetrics() { return performanceMetrics; }
    public void setPerformanceMetrics(PerformanceMetrics performanceMetrics) { this.performanceMetrics = performanceMetrics; }
}

/**
 * Nginx状态
 */
class NginxStatus {
    private String status;
    private int activeConnections;
    private int totalRequests;
    private Map<String, Object> upstreamStatus;
    
    // getters and setters
    public String getStatus() { return status; }
    public void setStatus(String status) { this.status = status; }
    public int getActiveConnections() { return activeConnections; }
    public void setActiveConnections(int activeConnections) { this.activeConnections = activeConnections; }
    public int getTotalRequests() { return totalRequests; }
    public void setTotalRequests(int totalRequests) { this.totalRequests = totalRequests; }
    public Map<String, Object> getUpstreamStatus() { return upstreamStatus; }
    public void setUpstreamStatus(Map<String, Object> upstreamStatus) { this.upstreamStatus = upstreamStatus; }
}

/**
 * 性能指标
 */
class PerformanceMetrics {
    private double averageResponseTime;
    private int requestsPerSecond;
    private double errorRate;
    private int activeConnections;
    private Map<String, Object> additionalMetrics;
    
    // getters and setters
    public double getAverageResponseTime() { return averageResponseTime; }
    public void setAverageResponseTime(double averageResponseTime) { this.averageResponseTime = averageResponseTime; }
    public int getRequestsPerSecond() { return requestsPerSecond; }
    public void setRequestsPerSecond(int requestsPerSecond) { this.requestsPerSecond = requestsPerSecond; }
    public double getErrorRate() { return errorRate; }
    public void setErrorRate(double errorRate) { this.errorRate = errorRate; }
    public int getActiveConnections() { return activeConnections; }
    public void setActiveConnections(int activeConnections) { this.activeConnections = activeConnections; }
    public Map<String, Object> getAdditionalMetrics() { return additionalMetrics; }
    public void setAdditionalMetrics(Map<String, Object> additionalMetrics) { this.additionalMetrics = additionalMetrics; }
}

/**
 * 负载均衡策略接口
 */
interface LoadBalancingStrategy {
    void configure();
    void optimize();
}

/**
 * 轮询策略
 */
class RoundRobinStrategy implements LoadBalancingStrategy {
    @Override
    public void configure() {
        // 配置轮询策略
    }
    
    @Override
    public void optimize() {
        // 优化轮询策略
    }
}

/**
 * 最少连接策略
 */
class LeastConnectionStrategy implements LoadBalancingStrategy {
    @Override
    public void configure() {
        // 配置最少连接策略
    }
    
    @Override
    public void optimize() {
        // 优化最少连接策略
    }
}

/**
 * IP哈希策略
 */
class IpHashStrategy implements LoadBalancingStrategy {
    @Override
    public void configure() {
        // 配置IP哈希策略
    }
    
    @Override
    public void optimize() {
        // 优化IP哈希策略
    }
}

/**
 * 加权策略
 */
class WeightedStrategy implements LoadBalancingStrategy {
    @Override
    public void configure() {
        // 配置加权策略
    }
    
    @Override
    public void optimize() {
        // 优化加权策略
    }
}