Spring Cloud Gateway: Introduction, Architecture, Setup and Demo

1. Gateway Overview

Spring Cloud Gateway serves as the entry point for traffic in a microservice system, offering routing, authentication, and rate‑limiting capabilities. It replaces Netflix Zuul as the second‑generation gateway framework in the Spring Cloud ecosystem.

2. Gateway Principles

Requests first reach the API gateway, which discovers service instances via a registration center (e.g., Nacos) and routes them to the appropriate microservice.

Spring Cloud Gateway architecture diagram.

3. Creating the Gateway Module

Use the Spring Initializr to generate a new module, select the "Gateway" dependency, and add the module to the multi‑module project.

4. Adding the Dependency

<module>passjava-gateway</module>

5. Configuring the Gateway

Import the common module that already includes the Nacos client, then add the @EnableDiscoveryClient annotation to the main application class.

@RefreshScope
@EnableDiscoveryClient
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class PassjavaGatewayApplication {
    public static void main(String[] args) {
        SpringApplication.run(PassjavaGatewayApplication.class, args);
    }
}

6. Gateway Demo (application.yml)

spring:
  cloud:
    gateway:
      routes:
        - id: route_qq
          uri: http://www.qq.com
          predicates:
            - Query=url,qq
        - id: route_baidu
          uri: http://www.baidu.com
          predicates:
            - Query=url,baidu

The first rule forwards requests containing url=qq to QQ, and the second forwards url=baidu to Baidu.

7. Code Repository

All source code is available at https://github.com/Jackson0714/PassJava-Platform .