Question

In my spring boot Application i have a scheduler which calls an API to generate token which expires in 15 min. Time of scheduler is also 15 min. please find below sample:

    public class TokenGeneration {
    private static String token = null;

    @Scheduled(15 minutes)
    public String fetchToken() {
        // api call which return token
        HttpEntity<model> response = restTemplate.exchange(uri, POST, entity, model.class);
        token = response.getBody().getAccessToken();
    }
 }

I stored token value in static variable from a non static method so that i can use this token variable wherever i want to use token value. is this right approach ? if not plz let me know how i can achieve this.

Do i need to make TokenGeneration class singleton so that only one instance of this class is made throught application?

Also i want to create an interceptor or filter in which i can set Authorization headers and token value so that each request will populate authorization header automatically, i don't want to set authorization header in each request like this :

HttpHeaders headers = new HttpHeaders();
    headers.set(CpsConstant.AUTHORIZATION, CpsConstant.BEARER + token);

So i tried with this custom interceptor :

 public class RestTemplateInterceptor implements ClientHttpRequestInterceptor{

@Override
public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {

     String token = TokenGeneration.token;
     request.getHeaders().add("Authorization", "Bearer " + token);    
     return execution.execute(request, body);
}

will add this interceptor in restTemplate in config file.

So is this right approach for both token generation as well as setting headers for each request or any improvements need to be done in this approach ? Me thinking of calling token generation method in interceptor in case of token is null like :

if(token == null){
//call token generation fetchToken method 
}

Answer 1

这是正确的方法
如果未指定，Spring默认范围始终为单例
可以使用拦截器，但是如果您想在没有令牌的情况下调用API怎么办？

最好的方法是使用两个单独的方法使用单独的类发送带有令牌和不带有令牌的请求

@Component
public class RestClient {

@Autowired
RestTemplate restTemplate;

public HttpHeaders getRequestHeaderBearer() {

HttpHeaders headers = new HttpHeaders();

headers.setContentType(MediaType.APPLICATION_JSON);
headers.add(HeaderParameters.AUTHORIZATION, HeaderParameters.BEARER + 
TokenGeneration.token);

return headers;

}

public HttpHeaders getRequestHeader() {

HttpHeaders headers = new HttpHeaders();

headers.setContentType(MediaType.APPLICATION_JSON);

return headers;

}

public <T> ResponseEntity<T> restExchangeBearer(String url, HttpMethod httpMethod,
    Class<T> classObj) {

return restTemplate.exchange(url, httpMethod,
    new HttpEntity<>("parameters", this.getRequestHeaderBearer()), classObj);

}

public <T> ResponseEntity<T> restExchange(String url, HttpMethod httpMethod,
    Class<T> classObj) {

return restTemplate.exchange(url, httpMethod,
    new HttpEntity<>("parameters", this.getRequestHeader()), classObj);

}
}

Spring Boot : Token authentication(bearer) in request headers in rest api when token also comes from calling another api

1 个答案: