JWT Utils

A Java utility library for handling JWT (JSON Web Token) operations. This library provides a simple and secure way to generate, validate, and parse JWT tokens.

Features

• Generate JWT tokens with custom claims
• Validate JWT tokens
• Extract claims from tokens
• Built-in support for subject and expiration claims
• Secure key generation using HMAC-SHA256

Requirements

• Java 11 or higher
• Maven

Installation

Add the following dependencies to your pom.xml:

<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt-api</artifactId>
    <version>0.11.5</version>
</dependency>
<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt-impl</artifactId>
    <version>0.11.5</version>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt-jackson</artifactId>
    <version>0.11.5</version>
    <scope>runtime</scope>
</dependency>

Usage

Basic Token Generation

// Initialize JwtUtils with a secret key and token validity duration
JwtUtils jwtUtils = new JwtUtils("your-256-bit-secret", 3600000); // 1 hour validity

// Generate a token
String token = jwtUtils.generateToken("userId123");

// Validate token
boolean isValid = jwtUtils.validateToken(token);

// Get subject from token
String subject = jwtUtils.getSubject(token);

Token with Custom Claims

Map<String, Object> claims = new HashMap<>();
claims.put("role", "ADMIN");
claims.put("email", "user@example.com");

String token = jwtUtils.generateToken("userId123", claims);

// Later, extract claims
Claims allClaims = jwtUtils.getAllClaims(token);
String role = allClaims.get("role", String.class);

Security Considerations

1. Use a strong secret key (at least 256 bits)
2. Keep your secret key secure and never expose it
3. Set appropriate token expiration times
4. Validate tokens before trusting their contents

Contributing

Feel free to submit issues and enhancement requests!