使用 `startup` 事件声明 `app` 启动前运行的函数：

```Python hl_lines="8"
{!../../docs_src/events/tutorial001.py!}
```

本例中，`startup` 事件处理器函数为项目数据库（只是**字典**）提供了一些初始值。

**FastAPI** 支持多个事件处理器函数。

只有所有 `startup` 事件处理器运行完毕，**FastAPI** 应用才开始接收请求。

## `shutdown` 事件

使用 `shutdown` 事件声明 `app` 关闭时运行的函数：

```Python hl_lines="6"
{!../../docs_src/events/tutorial002.py!}
```

![Events Diagram](../assets/images/events@2x.png)

Here’s a [sample event listener](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEventsNonConcurrent.java) that prints each event with a timestamp.

```java

  }

  fun assertEvent(
    id: String?,
    type: String?,
    data: String,
  ) {
    assertThat(nextEvent()).isEqualTo(Event(id, type, data))
  }

  fun assertOpen(): EventSource {
    val event = nextEvent() as Open
    return event.eventSource
  }

  fun assertClose() {
    nextEvent() as Closed
  }

  fun assertFailure(message: String?) {

        dispatcher.onEvent(event);
        delegate.artifactInstalling(event);
    }

    @Override
    public void artifactResolved(RepositoryEvent event) {
        dispatcher.onEvent(event);
        delegate.artifactResolved(event);
    }

    @Override
    public void artifactResolving(RepositoryEvent event) {
        dispatcher.onEvent(event);
        delegate.artifactResolving(event);
    }

    @Override

    public void projectSkipped(ExecutionEvent event) {
        dispatcher.onEvent(event);
        delegate.projectSkipped(event);
    }

    @Override
    public void projectStarted(ExecutionEvent event) {
        dispatcher.onEvent(event);
        delegate.projectStarted(event);
    }

    @Override
    public void projectSucceeded(ExecutionEvent event) {
        dispatcher.onEvent(event);
        delegate.projectSucceeded(event);

events@2x.png...

# Events testen: Hochfahren – Herunterfahren

Wenn Sie in Ihren Tests Ihre Event-Handler (`startup` und `shutdown`) ausführen wollen, können Sie den `TestClient` mit einer `with`-Anweisung verwenden:

```Python hl_lines="9-12  20-24"
{!../../docs_src/app_testing/tutorial003.py!}

Note that transition event notification is a MinIO extension.

## Explore Further

- [MinIO | Golang Client API Reference](https://min.io/docs/minio/linux/developers/go/API.html)

import org.apache.maven.api.annotations.Nonnull;

/**
 * A listener for session events.
 * TODO: open this to other events like similar to {@code org.apache.maven.eventspy.EventSpy}
 *
 * @since 4.0.0
 */
@Experimental
@FunctionalInterface
@Consumer
public interface Listener {
    void onEvent(@Nonnull Event event);

  }

  @Test
  fun idCleared() {
    consumeEvents(
      """
      |data: first event
      |id: 1
      |
      |data: second event
      |id
      |
      |data: third event
      |
      |
      """.trimMargin(),
    )
    assertThat(callbacks.remove()).isEqualTo(Event("1", null, "first event"))