Custom Authentication Via JSON login request in Spring Security

CustomUsernamePasswordAuthenticationFilter.java

@Slf4j
public class CustomUsernamePasswordAuthenticationFilter extends UsernamePasswordAuthenticationFilter {

	@Override
	public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response)
			throws AuthenticationException {
		if (!request.getMethod().equals("POST")) {
			throw new AuthenticationServiceException(
					"Authentication method not supported: " + request.getMethod());
		}
		if (request.getHeader("Content-Type").equals(MediaType.APPLICATION_JSON.toString())) {

			LoginRequest loginRequest = this.getLoginRequest(request);

			UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken(loginRequest.getUsername()
					, loginRequest.getPassword());

			setDetails(request, authRequest);

			return this.getAuthenticationManager().authenticate(authRequest);
		}

		return super.attemptAuthentication(request, response);
	}

	private LoginRequest getLoginRequest(HttpServletRequest request) {
		BufferedReader reader = null;
		LoginRequest loginRequest = null;
		try {
			reader = request.getReader();
			Gson gson = new Gson();
			loginRequest = gson.fromJson(reader, LoginRequest.class);
		} catch (IOException ex) {
			log.error("CustomUsernamePasswordAuthenticationFilter#getLoginRequest", ex);
		} finally {
			try {
				reader.close();
			} catch (IOException ex) {
				log.error("CustomUsernamePasswordAuthenticationFilter#getLoginRequest", ex);
			}
		}

		if (loginRequest == null) {
			loginRequest = new LoginRequest();
		}

		return loginRequest;
	}

	@Data
	private static class LoginRequest {

		String username;
		String password;

	}
}