thread_add_read和thread_add_write是什么意思

`thread_add_read`和`thread_add_write`是指在多线程编程中对文件描述符进行读写监听的函数。

`thread_add_read`函数用于向多线程程序中添加一个文件描述符，以便在该文件描述符上可以进行读取操作。当该文件描述符上发生读取事件时，多线程程序会调用相应的回调函数进行处理。

`thread_add_write`函数用于向多线程程序中添加一个文件描述符，以便在该文件描述符上可以进行写入操作。当该文件描述符上发生写入事件时，多线程程序会调用相应的回调函数进行处理。

这两个函数通常与多路复用技术（如select、poll、epoll等）结合使用，以实现高效的网络编程。

相关问题

java钢琴_Java swing实现支持录音等功能的钢琴程序

Java Swing是一种基于Java语言的图形用户界面(GUI)工具包。使用Java Swing，可以轻松地创建各种GUI应用程序，包括钢琴程序。以下是一个简单的Java Swing钢琴程序示例，支持录音等功能。

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.sound.midi.*;
import javax.swing.*;

public class Piano extends JFrame implements ActionListener {
    private static final long serialVersionUID = 1L;

    private JButton[] whiteKeys = new JButton[7];
    private JButton[] blackKeys = new JButton[5];
    private JButton recordButton;
    private JButton playButton;
    private JButton stopButton;
    private boolean isRecording = false;
    private boolean isPlaying = false;
    private Sequence sequence;
    private Sequencer sequencer;
    private Track track;
    private int currentTick;
    private ByteArrayOutputStream byteArrayOutputStream;
    private AudioFormat audioFormat;
    private TargetDataLine targetDataLine;
    private AudioInputStream audioInputStream;
    private byte[] audioData;

    public Piano() {
        setTitle("Java Piano");
        setSize(800, 300);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        setLayout(new BorderLayout());

        JPanel keyboardPanel = new JPanel();
        keyboardPanel.setLayout(new GridLayout(1, 0));

        // Add white keys
        String[] whiteNotes = {"C", "D", "E", "F", "G", "A", "B"};
        for (int i = 0; i < 7; i++) {
            whiteKeys[i] = new JButton(whiteNotes[i]);
            whiteKeys[i].setPreferredSize(new Dimension(80, 200));
            whiteKeys[i].addActionListener(this);
            keyboardPanel.add(whiteKeys[i]);
        }

        // Add black keys
        String[] blackNotes = {"C#", "D#", "", "F#", "G#", "A#"};
        for (int i = 0; i < 6; i++) {
            if (i != 2) {
                blackKeys[i] = new JButton(blackNotes[i]);
                blackKeys[i].setPreferredSize(new Dimension(50, 120));
                blackKeys[i].setBackground(Color.BLACK);
                blackKeys[i].setOpaque(true);
                blackKeys[i].addActionListener(this);
                keyboardPanel.add(blackKeys[i]);
            }
        }

        // Add record, play, and stop buttons
        JPanel controlPanel = new JPanel();
        controlPanel.setLayout(new FlowLayout());

        recordButton = new JButton("Record");
        recordButton.addActionListener(this);
        controlPanel.add(recordButton);

        playButton = new JButton("Play");
        playButton.addActionListener(this);
        controlPanel.add(playButton);

        stopButton = new JButton("Stop");
        stopButton.addActionListener(this);
        controlPanel.add(stopButton);

        add(keyboardPanel, BorderLayout.CENTER);
        add(controlPanel, BorderLayout.SOUTH);

        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == recordButton) {
            if (!isRecording) {
                isRecording = true;
                recordButton.setText("Stop Recording");
                startRecording();
            } else {
                isRecording = false;
                recordButton.setText("Record");
                stopRecording();
            }
        } else if (e.getSource() == playButton) {
            if (!isPlaying) {
                isPlaying = true;
                playButton.setText("Stop Playing");
                startPlaying();
            } else {
                isPlaying = false;
                playButton.setText("Play");
                stopPlaying();
            }
        } else {
            JButton button = (JButton) e.getSource();
            String note = button.getText();
            playSound(note);
            if (isRecording) {
                addNoteToSequence(note);
            }
        }
    }

    private void startRecording() {
        try {
            audioFormat = getAudioFormat();
            DataLine.Info dataLineInfo = new DataLine.Info(TargetDataLine.class, audioFormat);
            targetDataLine = (TargetDataLine) AudioSystem.getLine(dataLineInfo);
            targetDataLine.open(audioFormat);
            targetDataLine.start();

            byteArrayOutputStream = new ByteArrayOutputStream();
            audioData = new byte[1024];

            new Thread(new Runnable() {
                public void run() {
                    while (isRecording) {
                        int numBytesRead = targetDataLine.read(audioData, 0, audioData.length);
                        byteArrayOutputStream.write(audioData, 0, numBytesRead);
                    }
                }
            }).start();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private void stopRecording() {
        try {
            targetDataLine.stop();
            targetDataLine.close();
            byteArrayOutputStream.close();

            byte[] byteArray = byteArrayOutputStream.toByteArray();
            ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArray);
            audioInputStream = new AudioInputStream(byteArrayInputStream, audioFormat, byteArray.length / audioFormat.getFrameSize());

            // Convert audio data to MIDI sequence
            AudioToMidiConverter converter = new AudioToMidiConverter();
            sequence = converter.convert(audioInputStream);

            // Create new track to add notes to
            sequencer = MidiSystem.getSequencer();
            sequencer.open();
            sequence.deleteTrack(sequence.getTracks()[0]);
            track = sequence.createTrack();
            currentTick = 0;
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private void startPlaying() {
        try {
            sequencer.setSequence(sequence);
            sequencer.start();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private void stopPlaying() {
        sequencer.stop();
        sequencer.close();
    }

    private void addNoteToSequence(String note) {
        try {
            int velocity = 127;
            int duration = 100;
            int pitch = getMidiPitch(note);
            ShortMessage messageOn = new ShortMessage(ShortMessage.NOTE_ON, 0, pitch, velocity);
            track.add(new MidiEvent(messageOn, currentTick));
            currentTick += duration;
            ShortMessage messageOff = new ShortMessage(ShortMessage.NOTE_OFF, 0, pitch, velocity);
            track.add(new MidiEvent(messageOff, currentTick));
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private void playSound(String note) {
        try {
            Synthesizer synthesizer = MidiSystem.getSynthesizer();
            synthesizer.open();
            MidiChannel[] channels = synthesizer.getChannels();
            int velocity = 127;
            int pitch = getMidiPitch(note);
            channels[0].noteOn(pitch, velocity);
            Thread.sleep(100);
            channels[0].noteOff(pitch, velocity);
            synthesizer.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private int getMidiPitch(String note) {
        String[] notes = {"C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"};
        int[] pitches = {60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71};
        for (int i = 0; i < notes.length; i++) {
            if (note.equals(notes[i])) {
                return pitches[i];
            }
        }
        return 0;
    }

    private AudioFormat getAudioFormat() {
        float sampleRate = 44100.0F;
        int sampleSizeInBits = 16;
        int channels = 1;
        boolean signed = true;
        boolean bigEndian = false;
        return new AudioFormat(sampleRate, sampleSizeInBits, channels, signed, bigEndian);
    }

    public static void main(String[] args) {
        new Piano();
    }
}

这个程序使用Java Swing创建了一个钢琴界面，包括白键和黑键。它还包括三个按钮：录音，播放和停止。当用户按下一个键时，程序将播放相应的音符，并且如果正在录音，则将该音符添加到MIDI序列中。当用户按下录音按钮时，程序开始录制音频，并将其转换为MIDI序列。当用户按下播放按钮时，程序将播放MIDI序列中的音符。

rtthread用gpio模拟iic

在RT-Thread中，可以通过GPIO模拟I2C总线，实现对I2C设备的通信。具体实现步骤如下：

1. 定义GPIO引脚

在RT-Thread的board.h文件中定义I2C使用的GPIO引脚，例如：

#define I2C_SCL_PIN     GET_PIN(A, 5)
#define I2C_SDA_PIN     GET_PIN(A, 6)

2. 初始化GPIO引脚

在I2C驱动的初始化函数中，初始化GPIO引脚，例如：

rt_pin_mode(I2C_SCL_PIN, PIN_MODE_OUTPUT_OD);
rt_pin_mode(I2C_SDA_PIN, PIN_MODE_OUTPUT_OD);

3. 实现I2C读写函数

实现I2C的读写函数，基于GPIO模拟I2C总线，例如：

static rt_uint8_t i2c_sda_read(void)
{
    return rt_pin_read(I2C_SDA_PIN);
}

static rt_uint8_t i2c_scl_read(void)
{
    return rt_pin_read(I2C_SCL_PIN);
}

static void i2c_sda_set(rt_uint8_t state)
{
    rt_pin_write(I2C_SDA_PIN, state);
}

static void i2c_scl_set(rt_uint8_t state)
{
    rt_pin_write(I2C_SCL_PIN, state);
}

static void i2c_gpio_delay(rt_uint32_t us)
{
    rt_hw_us_delay(us);
}

static struct rt_i2c_bus_device i2c_bus;
static const struct rt_i2c_bit_ops i2c_bit_ops =
{
    i2c_sda_read, i2c_sda_set,
    i2c_scl_read, i2c_scl_set,
    i2c_gpio_delay,
};

4. 注册I2C设备

在I2C驱动的初始化函数中，注册I2C设备并绑定读写函数，例如：

rt_i2c_bit_add_bus(&i2c_bus, "i2c", &i2c_bit_ops);

rt_device_i2c_register("i2c0", &i2c_bus, NULL);

至此，通过GPIO模拟I2C总线的驱动就完成了。在使用时，可以通过RT-Thread的I2C API来访问I2C设备。