# Einstellungen und Umgebungsvariablen { #settings-and-environment-variables }

In vielen Fällen benötigt Ihre Anwendung möglicherweise einige externe Einstellungen oder Konfigurationen, zum Beispiel geheime Schlüssel, Datenbank-Anmeldeinformationen, Anmeldeinformationen für E-Mail-Dienste, usw.

Die meisten dieser Einstellungen sind variabel (können sich ändern), wie z. B. Datenbank-URLs. Und vieles könnten schützenswerte, geheime Daten sein.

Mais vous pouvez indiquer à **FastAPI** de la traiter comme une variable de body en utilisant `Body` :

{* ../../docs_src/body_multiple_params/tutorial003_an_py310.py hl[23] *}

Dans ce cas, **FastAPI** s'attendra à un body semblable à :

```JSON
{
    "item": {

 * on the same [call] to process the next event.
 *
 * By forcing the list of listeners to change after every event, we can detect if buggy code caches
 * a stale [EventListener] in a field or local variable.
 */
class EventListenerRelay(
  val call: Call,
  val eventRecorder: EventRecorder,
) {
  private val eventListenerAdapter =
    EventListenerAdapter()
      .apply {
        listeners += ::onEvent

/// tip | Consejo

Para entender las variables de entorno, puedes leer [Variables de Entorno](../environment-variables.md){.internal-link target=_blank}.

///

## Tipos y validación { #types-and-validation }

     * Sets the currently active session. Some legacy components are basically stateful and their API is missing
     * parameters that would be required to delegate to a stateless component. Saving the session (in a thread-local
     * variable) is our best effort to record any state that is required to enable proper delegation.
     *
     * @param session The currently active session, may be {@code null}.
     */
    void setSession(MavenSession session);

@REM specific language governing permissions and limitations
@REM under the License.

@REM -----------------------------------------------------------------------------
@REM Apache Maven Encrypt Script
@REM
@REM Environment Variable Prerequisites
@REM
@REM   JAVA_HOME           (Optional) Points to a Java installation.
@REM   MAVEN_BATCH_ECHO    (Optional) Set to 'on' to enable the echoing of the batch commands.

:skipRcPre

@setlocal

set ERROR_CODE=0

@REM To isolate internal variables from possible post scripts, we use another setlocal
@setlocal

@REM ==== START VALIDATION ====
if not "%JAVA_HOME%" == "" goto OkJHome

echo. >&2
echo Error: JAVA_HOME not found in your environment. >&2
echo Please set the JAVA_HOME variable in your environment to match the >&2
echo location of your Java installation. >&2
echo. >&2

  /** Adds the given pair of values to the dataset. */
  public void add(double x, double y) {
    // We extend the recursive expression for the one-variable case at Art of Computer Programming
    // vol. 2, Knuth, 4.2.2, (16) to the two-variable case. We have two value series x_i and y_i.
    // We define the arithmetic means X_n = 1/n \sum_{i=1}^n x_i, and Y_n = 1/n \sum_{i=1}^n y_i.

func (ct ColumnType) AutoIncrement() (isAutoIncrement bool, ok bool) {
	return ct.AutoIncrementValue.Bool, ct.AutoIncrementValue.Valid
}

// Length returns the column type length for variable length column types
func (ct ColumnType) Length() (length int64, ok bool) {
	if ct.LengthValue.Valid {
		return ct.LengthValue.Int64, true
	}
	return ct.SQLColumnType.Length()
}

    public void addReplyTo(String replyTo, String personal) {
        doAddReplyTo(replyTo, personal);
    }

    // -----------------------------------------------------
    //                                  Application Variable
    //                                  --------------------
    /**
     * Set the value of hostname, used in parameter comment. <br>