answer:`org.java_websocket.client.WebSocketClient` 类中获取 WebSocket 缓冲区对象的方法是通过订阅 `org.java_websocket.WebSocket` 对象的 `onMessage` 方法来获取。当 WebSocket 接收到消息时，`WebSocket` 对象会将数据包作为 `ByteBuffer` 对象传递给 `onMessage` 方法。我们可以将其赋值给一个实例变量，以在稍后的代码中使用。 下面是一个示例代码，它展示了如何通过订阅 `onMessage` 事件来获取 WebSocket 缓冲区： ```java import java.net.URI; import java.nio.ByteBuffer; import org.java_websocket.client.WebSocketClient; import org.java_websocket.handshake.ServerHandshake; public class WebSocketClientDemo { public static void main(String[] args) { try { WebSocketClient client = new WebSocketClient(new URI("ws://localhost:8080")) { private ByteBuffer buffer; @Override public void onOpen(ServerHandshake handshakedata) { System.out.println("WebSocket opened"); } @Override public void onMessage(ByteBuffer buffer) { System.out.println("WebSocket received message"); this.buffer = buffer; } @Override public void onError(Exception ex) { ex.printStackTrace(); } @Override public void onClose(int code, String reason, boolean remote) { System.out.println("WebSocket closed"); } }; client.connect(); } catch (Throwable t) { t.printStackTrace(); } } } ``` 在上述代码中，我们以 `ByteBuffer` 的形式保存 WebSocket 缓冲区，即在 `onMessage` 方法中接收到数据包后，将其赋值给 `this.buffer` 变量。在稍后的代码中，我们可以从 `this.buffer` 变量中读取数据。 需要注意的是，如果需要频繁读取 WebSocket 缓冲区中的数据，我们建议在读取之前再额

answer:L1和L2架构图都是嵌入式系统中常用的架构图。 L1架构图指的是单层软件架构图，其中有一个中央处理器（CPU）和一些外设，如内存、外部存储器、通信接口等。该架构图简单明了，适合于小型嵌入式系统。 L2架构图又称为多层软件架构图，其中有多层软件，如应用程序、操作系统、驱动程序等。该架构图适用于大型嵌入式系统，它能够简化软件结构，提高系统的可维护性和可扩展性。

answer:Star delta and soft starter are two different types of electrical connections used in motor control applications. Star Delta: The star delta connection is a starter method that is used for controlling three-phase AC motors. The main aim of using the star delta connection is to reduce the starting current of the motor, which helps protect the motor against voltage drops, overheating, and damage. This electrical connection technique is called star delta because the motor is connected initially in the 'star' configuration during the starting phase and later switched to 'delta' during the running phase. The star-delta starter also has several other benefits, such as reduced equipment cost, increased motor speed control, and low voltage drops across the motor and cables. Soft starter: A soft starter is an electronic device that is used to control the starting and stopping of an AC electric motor with reduced voltage. The primary aim of using the soft starter is to reduce the impact of high inrush current when a motor starts, which can lead to damage to the equipment and power grid. The soft starter uses a voltage ramp to gradually increase the voltage supplied to the motor, enabling it to start smoothly and safely. This electrical connection technique also has additional advantages, such as eliminating mechanical shocks, reducing energy consumption, and increasing motor life span. In summary, the primary difference between star delta and soft starter electrical connections is that the star-delta connection is primarily used for reducing the starting current of three-phase AC motors, while a soft starter is used to ensure smooth and safe starting without inrush current.

answer:B. {-7, -6, -5, -4}