FusionAuth Java Client

Java Client Library

The Java client library allows you to integrate FusionAuth with your Java application.

Source Code:

Maven Dependency

<dependency>
  <groupId>io.fusionauth</groupId>
  <artifactId>fusionauth-java-client</artifactId>
  <version>1.1.0</version>
</dependency>

When building your application, utilize the version that corresponds to the version of FusionAuth your running. View all available versions on https://search.maven.org

Using the FusionAuth and consuming the ClientResponse

The Java client has two styles of use, the first return a ClientResponse object. This object contains everything that occurred while communicating with the FusionAuth server. If the communication with the server encountered a network issue, the ClientResponse.exception might contain an IOException.

The following code assumes FusionAuth is running on http://localhost:9011 and uses an API key 6b87a398-39f2-4692-927b-13188a81a9a3, you will need to supply your own API key, and if you are not running FusionAuth locally, your host parameter may be different.

Here is an example of using the retrieveUserByEmail method to retrieve a User by an email address.

import com.inversoft.error.Errors;
import io.fusionauth.client.FusionAuthClient;
import io.fusionauth.domain.User;
import io.fusionauth.domain.api.UserResponse;
import com.inversoft.rest.ClientResponse;

public class Example {
  private final FusionAuthClient client;

  public Example() {
    client = new FusionAuthClient("6b87a398-39f2-4692-927b-13188a81a9a3", "http://localhost:9011");
  }

  public User getUserByEmail(String email) {
    ClientResponse<UserResponse, Errors> response = client.retrieveUserByEmail(email);
    if (response.wasSuccessful()) {
      return response.successResponse.user;
    } else if (response.errorResponse != null) {
      // Error Handling
      Errors errors = response.errorResponse;
    } else if (response.exception != null) {
      // Exception Handling
      Exception exception = response.exception;
    }

    return null;
  }
}

Using the Lambda Delegate

The Java Client may also be used along with our Lambda delegate that provides exception handling and allows you to write code assuming a happy path. Here is the same example from above using the lambda delegate:

import com.inversoft.error.Errors;
import io.fusionauth.client.LambdaDelegate;
import io.fusionauth.client.FusionAuthClient;
import io.fusionauth.domain.User;
import com.inversoft.rest.ClientResponse;

public class Example {
  private final String apiKey = "6b87a398-39f2-4692-927b-13188a81a9a3";

  private final String fusionauthURL = "http://localhost:9011";

  private final FusionAuthClient client;

  private final LambdaDelegate delegate;

  public Example(String apiKey, String fusionauthURL) {
    this.client = new FusionAuthClient(apiKey, fusionauthURL);
    this.delegate = new LambdaDelegate(this.client, (r) -> r.successResponse, this::handleError);
  }

  public User getUserByEmail(String email) {
    return delegate.execute(c -> c.retrieveUserByEmail("user@example.com")).user;
  }

  private <T, U> void handleError(ClientResponse<T, U> clientResponse) {
    if (clientResponse.exception != null) {
      // Handle the exception
      ...
    } else if (clientResponse.errorResponse != null && clientResponse.errorResponse instanceof Errors) {
      // Handle errors
      ...
    }
  }
}

As you can see, using the lambda delegate requires less code to handle the success response and the error handling code can be re-used.