https://github.com/gabrielbb/jwt-java-utility

JSON Web Token Utility Class example implemented in Java using the library "JJWT"
https://github.com/gabrielbb/jwt-java-utility

Last synced: 14 days ago
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JSON Web Token Utility Class example implemented in Java using the library "JJWT"

• Host: GitHub
• URL: https://github.com/gabrielbb/jwt-java-utility
• Owner: GabrielBB
• Created: 2018-03-14T01:48:38.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-03-15T17:23:24.000Z (over 6 years ago)
• Last Synced: 2024-10-11T04:03:50.994Z (28 days ago)
• Language: Java
• Homepage:
• Size: 7.81 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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# jwt-java-utility

## JSON Web Token Utility Class example implemented in Java using the library JJWT

### Requirements:

Add the library JJWT as a dependency in your project:

Maven:

```xml

    io.jsonwebtoken

    jjwt

    0.9.0

```

Gradle:

```groovy

dependencies {

    compile 'io.jsonwebtoken:jjwt:0.9.0'

}

```

### The Models

Let's see the two model classes used in this example.

#### User.java

```java

public class User {

    private String name;

    private Role role;

}

```

#### Role.java

```java

public class Role {

    private int id;

    private String description;

}

```

### The Utility Class

```java

package com.github.gabrielbb;

import com.github.gabrielbb.models.Role;

import com.github.gabrielbb.models.User;

import io.jsonwebtoken.Claims;

import io.jsonwebtoken.Jwts;

import io.jsonwebtoken.SignatureAlgorithm;

import java.util.Date;

import java.util.concurrent.TimeUnit;

/**

 * Created by Gabriel Basilio Brito on 3/13/2018.

 */

public class JWTUtility {

    private final static int EXPIRATION_HOURS = 1;

    private final byte[] signatureKeyBytes;

    public JWTUtility(String signatureKey) { // Pass your signature key to make an instance. Use a random secret string

        this.signatureKeyBytes = signatureKey.getBytes();

    }

    public String getToken(User user) {

        Date now = new Date();

        return Jwts.builder()

                .setSubject(user.getId()) // Subject is the unique identifier, this is usually an user ID or unique username

                .signWith(SignatureAlgorithm.HS512, signatureKeyBytes)

                .claim("role", user.getRole().getDescription()) // Add more claims according to your model class

                .setIssuedAt(now)

                .setExpiration(getExpirationTime(now))

                .compact();

    }

    public User getUser(String token) throws SignatureException {

        Claims claims = Jwts.parser()

        .setSigningKey(signatureKeyBytes)

        .parseClaimsJws(token)

        .getBody();

        Role role = new Role();

        role.setDescription(claims.get("role").toString());

        

        /* 

        You can insert a List as a claim if you need to, just cast it while getting it back. For Example:

        List permissions = (List) claims.get("permissions");

        */

        User user = new User();

        user.setId(claims.getSubject());

        user.setRole(role);

        return user;

    }

    private Date getExpirationTime(Date now) {

        Long expireInMillis = TimeUnit.HOURS.toMillis(EXPIRATION_HOURS);

        return new Date(expireInMillis + now.getTime());

    }

}

```

### Testing it

Testing this is very easy. You can check the unit testing in the code and run it. 

We just have to instance User and generate a token from it. With your generated token, try to get back an User object and validate it has the same values in the properties.