Spring boot读书笔记一REST API

REST API Definition
REST = Representational State Transfer

A REST API is a web service that uses HTTP methods to perform operations on resources, following specific architectural principles.

Core Concepts
Resource-Based: Everything is treated as a resource with a unique URL

/users/123        (a specific user)
/products         (collection of products)
/orders/456       (a specific order)

HTTP Methods:

• GET - Retrieve data
• POST - Create new resource
• PUT - Update entire resource
• PATCH - Update part of resource
• DELETE - Remove resource

Simple REST API Example

@RestController
@RequestMapping("/api/config")
public class ConfigRestController {
    
    @Autowired
    private AppProperties appProperties;
    
    // GET /api/config - Retrieve configuration
    @GetMapping
    public AppProperties getConfig() {
        return appProperties;
    }
    
    // GET /api/config/security - Get security settings
    @GetMapping("/security")
    public AppProperties.Security getSecurity() {
        return appProperties.getSecurity();
    }
}

HTTP Request/Response Flow
Request:

• GET /api/config HTTP/1.1
• Host: localhost:8080
• Accept: application/json
  Response:

{
  "name": "MyApp",
  "ip": "192.168.1.1",
  "port": 8080,
  "security": {
    "enabled": true,
    "token": "abc123",
    "roles": ["admin", "user"]
  }
}

Key Characteristics

• Stateless: Each request contains all needed information
• Cacheable: Responses can be cached for performance
• Uniform Interface: Consistent way to interact with resources
• JSON/XML: Data exchanged in standard formats

Real-World Usage
Mobile Apps: Fetch user data, submit forms
Web Applications: AJAX calls to load/update data
Microservices: Services communicate via REST APIs
Third-party Integration: Connect with external systems

The AppProperties class would be perfect for a REST API that manages application configuration - clients could retrieve or update configuration settings through HTTP requests.