JwtCustomizer.java

package example;

import org.springframework.security.oauth2.core.OAuth2TokenType;
import org.springframework.security.oauth2.server.authorization.JwtEncodingContext;
import org.springframework.security.oauth2.server.authorization.OAuth2TokenCustomizer;
import org.springframework.stereotype.Component;

@Component
public class JwtCustomizer implements OAuth2TokenCustomizer<JwtEncodingContext> {

    @Override
    public void customize(JwtEncodingContext context) {
        if (OAuth2TokenType.ACCESS_TOKEN.equals(context.getTokenType())) {
            context.getClaims().claim("key", "value");
        }
    }
}