Quickly Set Up Spring Authorization Server with Zero‑Config

Background

Spring has discontinued maintenance of the Spring Security OAuth project, and the Spring Authorization Server (SAS) now provides a production‑ready OAuth2 authorization server within the Spring ecosystem.

Zero‑Configuration SAS Starter

Add the following Maven dependency to enable the SAS starter with no additional configuration (requires Spring Boot 3.x):

<code>&lt;dependency&gt;
  &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
  &lt;artifactId&gt;spring-boot-starter-oauth2-authorization-server&lt;/artifactId&gt;
&lt;/dependency&gt;</code>

You can also select the starter directly in Spring Initializr.

Authorization Server Usage

Server Setup

Include the SAS starter and the Spring Web starter:

<code>&lt;dependency&gt;
  &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
  &lt;artifactId&gt;spring-boot-starter-oauth2-authorization-server&lt;/artifactId&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
  &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
  &lt;artifactId&gt;spring-boot-starter-web&lt;/artifactId&gt;
&lt;/dependency&gt;</code>

Configuration

Add two client registrations to

application.yml

(or

application.properties

).

<code># Client Credentials Grant
spring.security.oauth2.authorizationserver.client.client-1.registration.client-id=admin-client
spring.security.oauth2.authorizationserver.client.client-1.registration.client-secret={bcrypt}$2a$10$jdJGhzsiIqYFpjJiYWMl/eKDOd8vdyQis2aynmFN0dgJ53XvpzzwC
spring.security.oauth2.authorizationserver.client.client-1.registration.client-authentication-methods=client_secret_basic
spring.security.oauth2.authorizationserver.client.client-1.registration.authorization-grant-types=client_credentials
spring.security.oauth2.authorizationserver.client.client-1.registration.scopes=user.read,user.write

# Authorization Code Grant
spring.security.oauth2.authorizationserver.client.client-2.registration.client-id=admin-client2
spring.security.oauth2.authorizationserver.client.client-2.registration.client-secret={noop}secret
spring.security.oauth2.authorizationserver.client.client-2.registration.client-authentication-methods=client_secret_basic
spring.security.oauth2.authorizationserver.client.client-2.registration.authorization-grant-types=authorization_code,refresh_token
spring.security.oauth2.authorizationserver.client.client-2.registration.redirect-uris[0]=https://pig4cloud.com
spring.security.oauth2.authorizationserver.client.client-2.registration.scopes=user.read,user.write</code>

Test Calls

1️⃣ Client Credentials Token

POST

/oauth2/token

with body:

<code>grant_type: client_credentials
scope: user.read</code>

2️⃣ Authorization Code Token

Obtain the code via

http://localhost:8080/oauth2/authorize?client_id=admin-client2&response_type=code&redirect_uri=https://pig4cloud.com

, then POST

/oauth2/token

with body:

<code>grant_type: authorization_code
scope: user.read
code: &lt;authorization_code_here&gt;
redirect_uri: https://pig4cloud.com</code>

3️⃣ Refresh Token

<code>grant_type: refresh_token
refresh_token: &lt;refresh_token_here&gt;</code>

4️⃣ Introspection Endpoint

<code>token: &lt;access_token_here&gt;</code>

5️⃣ Revoke Token

<code>token: &lt;token_to_revoke&gt;</code>

Resource Server Usage

Setup

Add the resource‑server and web starters:

<code>&lt;dependency&gt;
  &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
  &lt;artifactId&gt;spring-boot-starter-oauth2-resource-server&lt;/artifactId&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
  &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
  &lt;artifactId&gt;spring-boot-starter-web&lt;/artifactId&gt;
&lt;/dependency&gt;</code>

Configuration

Specify the issuer URI of the authorization server:

<code>spring.security.oauth2.resourceserver.jwt.issuer-uri=http://127.0.0.1:8080</code>

Business Code Test

<code>@GetMapping
public String principal(Principal principal) {
    return principal.getName();
}</code>

Test with curl:

<code>curl --location --request GET 'http://127.0.0.1:8081/' \
--header 'Authorization: Bearer XXX'</code>

References

[1] PIG Microservice Development Platform – https://github.com/pig-mesh/pig