Detailed instructions on how to configure Gateway in a Spring Cloud project

In Spring Cloud, you can use Spring Cloud Gateway as an API gateway. Here are detailed instructions on how to configure Gateway in a Spring Cloud project:

1. Add dependencies

pom.xmlAdd dependencies to the file spring-cloud-starter-gateway:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>

At the same time, make sure your project has added Spring Cloud dependency management:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

${spring-cloud.version}Is the Spring Cloud version you are using, for example: 2020.0.3.

2. Configure Gateway

Configure Gateway routing rules in or application.ymlfiles . application.propertiesHere's a simple example:

spring:
  cloud:
    gateway:
      routes:
      - id: user-service
        uri:://localhost:8081
        predicates:
        - Path=/user-service/**
        filters:
        - RewritePath=/user-service/(?<path>.*), /$\{
    
    path}

In this example, we configure a user-serviceroute named . When the request path /user-service/begins with , Gateway forwards the request to http://localhost:8081. At the same time, we use RewritePaththe filter to remove the prefix in the request path /user-service.

3. Enable Gateway

Add annotations to the Spring Boot main class @EnableDiscoveryClientto enable service discovery (if you are using service registration and discovery components, such as Eureka):

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
public class GatewayApplication {
    
    
    public static void main(String[] args) {
    
    
        SpringApplication.run(GatewayApplication.class, args);
    }
}

4. Configure service discovery (optional)

If you use a service registration and discovery component, such as Eureka, you can configure Gateway to use service discovery to automatically route requests. First, pom.xmladd spring-cloud-starter-netflix-eureka-clientdependencies to the file:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

Then, configure the Eureka client and Gateway routing rules in the application.ymlor file:application.properties

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

spring:
  cloud:
    gateway:
      routes:
      - id: user-service
        uri: lb://user-service
        predicates:
        - Path=/user-service/**
        filters:
        - RewritePath=/user-service/(?<path>.*), /$\{
    
    path}

In this example, we configure the route urias lb://user-serviceto indicate that the load balancer (LoadBalancer) is used to forward the request to user-servicethe service instance named.

That's it for the detailed instructions for configuring Gateway in a Spring Cloud project. You can adjust Gateway settings and routing rules according to your needs.