# Spring Cloud Gateway

Paul Tomoiu

●

Examples,

Spring,

Cloud,

Gateway

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Published 2023-07-07

This tutorial explains how to build a very simple Spring Cloud Gateway. This tutorial contains an example as well.

A gateway is a computer (software) that sits between different networks or applications. The gateway converts information, data or other communications from one protocol or format to another. Practically the gateway, receive a request and can transform it in any manner (for redirecting, security reason, adding/removing information from the body or from the header).

With Spring Boot, a simple Spring Cloud Gateway application is done by downloading a simple application from spring initializr. We need to add Gateway dependency as in the image below:

After that we need to add the routing information. This can be done in a Java class or in the config file.

In my example I will add the following into the application.yaml file:

server:
  port: 8080

logging:
  level:
    root: info
    no.embriq.api.gateway: debug

spring:
  cloud:
    gateway:
      routes:
        - id: "route name #1"
          uri: "http://www.hotmail.com"
          predicates:
            - Path=/hotmail

That's all. When a request hits the predicate (http://localhost/hotmail), the request is forwarded to uri (http://www.hotmail.com).

The same thing can be done using RouteLocator Bean.

You can see some example here as well.

With Spring Cloud Gateway you can modify a request as you wish. This could be done in a classical manner, but spring-cloud-starter-gateway dependency helps you a lot on this.