可以在客户端代码中手动验证event bus是否存在，避免发布消息到不存在的event bus。具体代码可以参考以下示例：

AwsEventBus eventBus = awsEventBridgeClient.describeEventBus(new DescribeEventBusRequest().withName(eventBusName)).getEventBus();
if (eventBus == null) {
    throw new RuntimeException("Event bus does not exist");
}
PutEventsRequestEntry event = new PutEventsRequestEntry()
    .withSource("my-app")
    .withDetailType("my-detail-type")
    .withDetail("{\"key1\":\"value1\",\"key2\":\"value2\"}");
PutEventsResult result = awsEventBridgeClient.putEvents(new PutEventsRequest()
    .withEntries(event)
    .withEventBusName(eventBusName));