JustAuth: A Simple Java Library for Third‑Party OAuth Login Integration

Hello everyone, I am Chen~

JustAuth, as you can see, is a third‑party authorization login utility library that frees us from cumbersome SDKs and makes login so easy !

JustAuth integrates dozens of domestic and overseas platforms such as GitHub, Gitee, Alipay, Sina Weibo, WeChat, Google, Facebook, Twitter, StackOverflow, etc.

Features

Rich OAuth platforms: Integrated dozens of third‑party platforms for rapid access.

Custom state: Supports custom state and cache strategies, allowing developers to choose any cache plugin.

Custom OAuth: Provides a unified interface to connect any OAuth site, making it easy to adapt your own OAuth service.

Custom HTTP: HTTP tool interface lets developers select the HTTP client that fits their project.

Custom Scope: Supports custom scopes to suit more business scenarios beyond simple login.

Simple code standards: Strictly follows Alibaba Java coding guidelines, with clear structure and simple logic.

Quick Start (using QQ as an example)

Apply for a developer account

If this is your first time, apply for a developer on the "QQ Connect Platform", create an application after approval, and copy three pieces of information: App ID, App Key, and the website callback domain.

Integrate JustAuth

Add the dependency:

<dependency>
    <groupId>me.zhyd.oauth</groupId>
    <artifactId>JustAuth</artifactId>
    <version>{latest-version}</version>
</dependency>

Create a request and add the three pieces of information from the first step:

AuthRequest authRequest = new AuthQqRequest(AuthConfig.builder()
    .clientId("App ID")
    .clientSecret("App Key")
    .redirectUri("Website callback domain")
    .build());

Generate the authorization URL:

// This link can be redirected in the backend or returned to the front end for redirection
String authorizeUrl = authRequest.authorize(AuthStateUtils.createState());

Or generate a static authorization page:

AuthRequest authRequest = AuthRequestBuilder.builder()
    .source("github")
    .authConfig(AuthConfig.builder()
        .clientId("clientId")
        .clientSecret("clientSecret")
        .redirectUri("redirectUri")
        .build())
    .build();
// Generate authorization page
authRequest.authorize("state");
// After login, a code (auth_code for Alipay) and state are returned; since version 1.8.0, AuthCallback can be used as the callback parameter
// Note: JustAuth keeps the state for 3 minutes by default; it will be cleared automatically after expiration.
authRequest.login(callback);

Or generate a dynamic authorization page:

AuthRequest authRequest = AuthRequestBuilder.builder()
    .source("gitee")
    .authConfig((source) -> {
        // Dynamically obtain AuthConfig based on source
        // Config can be fetched from SQL, files, etc.
        return AuthConfig.builder()
            .clientId("clientId")
            .clientSecret("clientSecret")
            .redirectUri("redirectUri")
            .build();
    })
    .build();
Assert.assertTrue(authRequest instanceof AuthGiteeRequest);
System.out.println(authRequest.authorize(AuthStateUtils.createState()));

The JustAuth team continues to add support for more platforms; interested readers can follow the project.

Open‑source address

https://github.com/justauth/JustAuth

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