Netflix/feign
Feign
Feign 是一个声明式的 Java HTTP 客户端，可自动生成 Web 服务客户端。它允许开发人员使用接口和注解定义 REST API 端点，无需编写手动请求和响应的样板代码。
该项目使用动态代理将方法调用映射到 HTTP 请求模板。它具有可插拔的编码器和解码器流水线，可将 Java 对象转换为请求体，并将响应体转换回类型安全的对象。
该库涵盖了广泛的集成功能，包括用于头部管理的请求拦截、用于弹性服务消费的基于策略的重试逻辑，以及用于 URI 的模板扩展。它还提供了记录 HTTP 流量日志和收集客户端性能指标的工具。
Features
- Declarative API Clients - Allows the definition of network endpoints using a declarative interface style with annotations.
- Pluggable Transformation Pipelines - Provides a pluggable pipeline of interchangeable encoders and decoders for transforming network payloads.
- API Request Automation - Automates the transformation of Java objects into formatted HTTP request bodies and query parameters.
- API Client Generators - Automates the generation of HTTP client implementations by mapping Java method calls to request templates.
- Microservices Communications - Standardizes synchronous communication between distributed microservices using a declarative client approach.
- HTTP Client Libraries - Serves as a comprehensive Java library for performing synchronous and asynchronous HTTP requests.
- HTTP Client Wrappers - Wraps complex HTTP communication into type-safe Java interfaces to eliminate request boilerplate.
- Client Services - Implements network clients that provide type-safe responses and automated request handling.
- Response Body Decoders - Transforms HTTP response payloads into type-safe Java objects using a pluggable decoding system.
- Dynamic Proxies - Uses runtime dynamic proxies to intercept interface calls and dispatch them as HTTP requests.
- Interface-to-Endpoint Mappings - Maps Java method signatures and annotations directly to HTTP endpoints to automate request construction.
- REST Clients - Implements an interface-based approach to define and execute requests against RESTful APIs.
- Query Parameter Encoders - Automatically formats maps and objects into valid query strings for dynamic request URL construction.
- Multipart Form Encoding - Serializes request payloads into multipart/form-data or url-encoded formats for web service transmission.
- Request Header Configuration - Provides comprehensive tools for defining static and dynamic HTTP request headers via annotations and interceptors.
- Retry Policies - Implements configurable retry policies to automatically re-execute failed network requests based on specific exceptions.
- HTTP Request Interceptors - Includes middleware components to intercept and modify outgoing requests for global header injection and authentication.
- API Error Handling Patterns - Processes non-success HTTP responses through a custom decoder to wrap failures into type-safe exceptions.
- Interceptor Sequences - Processes outgoing requests through an ordered sequence of interceptors to modify metadata or inject headers.
- Retry Strategies - Determines whether to re-execute failed network operations based on configurable policies and exception types.
- Resilience Retry Patterns - Implements configurable retry policies and failure handling to ensure resilient web service consumption.
- URI Template Expanders - Resolves placeholders in URIs and headers using standard template expansion rules and method parameters.
- External API Integrations - Facilitates integration with external REST services using custom interceptors and error handling.
- Request Body Attachers - Converts Java objects into HTTP request bodies using configurable encoders and template expansion.
- REST框架 - 声明式HTTP客户端连接器。
