Request-Response Model

Request-Response Lifecycle in Spring Boot

DispatcherServlet

The heart of Spring MVC, routes incoming HTTP requests to appropriate controllers.

Handler Mapping

Maps URL patterns (@RequestMapping, @GetMapping) to controller methods.

Controller Layer

@RestController for RESTful endpoints
@RequestBody/@ResponseBody for JSON serialization/deserialization

Service Layer

@Service annotation for business logic
@Transactional for transaction management

Repository Layer

Spring Data JPA for ORM mapping
@Repository for data access layer

Inter-Service Communication in Microservices

Synchronous Communication

OpenFeign client for service-to-service HTTP calls
Load balancing with Ribbon/Spring Cloud LoadBalancer

Asynchronous Communication

Spring Cloud Stream for message-driven architecture
RabbitMQ/Apache Kafka integration

Event-Driven Architecture

Domain events for loose coupling
Event sourcing pattern for eventual consistency

Timeout & Retry

@Retryable annotation for automatic retry
Circuit breaker pattern for fault tolerance

Performance Considerations

Connection Pooling

HikariCP for database connection pooling
Apache HttpClient for HTTP connection pooling

Caching

Spring Cache abstraction (@Cacheable) with Redis/Hazelcast integration

Async Processing

@Async annotation for non-blocking operations
CompletableFuture for async programming

API Gateway Pattern

Spring Cloud Gateway

Route definitions
Predicates
Filters

Rate Limiting

Redis-based rate limiting
Token bucket algorithm

Circuit Breaking

Resilience4j integration
Fallback mechanisms

Request/Response Transformation

Header manipulation
Body transformation

Security

JWT validation
OAuth2 integration
API key management

Load Balancing Strategies

Client-side Load Balancing

Spring Cloud LoadBalancer
Ribbon

Server-side Load Balancing

Nginx
HAProxy
AWS ALB

Health Checks

Spring Boot Actuator
Custom health indicators

Service Discovery Integration

Eureka
Consul
Kubernetes service discovery

Request Lifecycle Example

Performance Optimization

Request Optimization

Keep-alive connections
HTTP/2 multiplexing
Request batching
Compression (gzip)

Response Optimization

Response caching
Pagination
Field filtering
Data compression

Error Handling

Circuit breaker pattern
Retry mechanisms
Graceful degradation
Fallback responses

Monitoring & Observability

Request Tracing

Distributed tracing
Correlation IDs
Request timing
Error tracking

Metrics Collection

Request count
Response time
Error rate
Throughput

Logging Strategy

Structured logging
Log aggregation
Request/response logging
Security events