Spring Cloud Gateway

Step 1 : Create Gateway Service

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.4.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>com.GatewayService</groupId>
    <artifactId>GatewayService</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>GatewayService</name>
    <description>Spring Cloud Gateway Service</description>

    <properties>
        <java.version>17</java.version>
        <spring-cloud.version>2024.0.1</spring-cloud.version>
    </properties>

    <dependencies>
        <!-- Spring Cloud Gateway (Reactive) -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>

        <!-- Testing -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <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>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

application.properties

server.port=8111
spring.application.name=gateway-service

spring.cloud.gateway.routes[0].id=basic-service
spring.cloud.gateway.routes[0].uri=http://localhost:8081
spring.cloud.gateway.routes[0].predicates[0]=Path=/api/**
spring.cloud.gateway.routes[0].filters[0]=StripPrefix=1

Step 2 – Create one simple microservice

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.6.7</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.javatrainingschool</groupId>
	<artifactId>spring-boot-project</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>spring-boot-project</name>
	<description>Demo project for Spring Boot</description>
	<properties>
		<java.version>1.8</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

RestController class

package com.javatrainingschool;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/basic")
public class BasicController {
	
	@RequestMapping("/home")
	public String home() {
		return "This is home.";
	}
	
	@GetMapping("/welcome")
	public String welcome() {
		return "Welcome to this simple microservice";
	}

}

application.properties file

spring.application.name = mySampleService
server.port = 8081

Step 2 – Run and test the microservice through gateway

Hit the following url – http://localhost:8111/basic/home