1 添加依赖

<dependency>
	<groupId>com.googlecode.soundlibs</groupId>
	<artifactId>mp3spi</artifactId>
	<version>1.9.5.4</version>
</dependency>

<!-- 如果需要解码播放flac文件则引入这个jar包 -->
<dependency>
	<groupId>org.jflac</groupId>
	<artifactId>jflac-codec</artifactId>
	<version>1.5.2</version>
</dependency>

2 快速傅里叶变换

Java FFT 代码来源
Java Complex 代码来源

2.1 FFT.java

package com.xu.music.player.fft;

import java.util.stream.Stream;

public class FFT {

    /**
     * compute the FFT of x[], assuming its length is a power of 2
     *
     * @param x
     * @return
     */
    public static Complex[] fft(Complex[] x) {
        int n = x.length;

        // base case
        if (n == 1) {
            return new Complex[]{x[0]};
        }

        // radix 2 Cooley-Tukey FFT
        if (n % 2 != 0) {
            throw new RuntimeException("N is not a power of 2");
        }

        // fft of even terms
        Complex[] even = new Complex[n / 2];
        for (int k = 0; k < n / 2; k++) {
            even[k] = x[2 * k];
        }
        Complex[] q = fft(even);

        // fft of odd terms
        Complex[] odd = even; // reuse the array
        for (int k = 0; k < n / 2; k++) {
            odd[k] = x[2 * k + 1];
        }
        Complex[] r = fft(odd);

        // combine
        Complex[] y = new Complex[n];
        for (int k = 0; k < n / 2; k++) {
            double kth = -2 * k * Math.PI / n;
            Complex wk = new Complex(Math.cos(kth), Math.sin(kth));
            y[k] = q[k].plus(wk.times(r[k]));
            y[k + n / 2] = q[k].minus(wk.times(r[k]));
        }
        return y;
    }

    /**
     * compute the inverse FFT of x[], assuming its length is a power of 2
     *
     * @param x
     * @return
     */
    public static Complex[] ifft(Complex[] x) {
        int n = x.length;
        Complex[] y = new Complex[n];

        // take conjugate
        for (int i = 0; i < n; i++) {
            y[i] = x[i].conjugate();
        }

        // compute forward FFT
        y = fft(y);

        // take conjugate again
        for (int i = 0; i < n; i++) {
            y[i] = y[i].conjugate();
        }

        // divide by N
        for (int i = 0; i < n; i++) {
            y[i] = y[i].scale(1.0 / n);
        }

        return y;

    }

    /**
     * compute the circular convolution of x and y
     *
     * @param x
     * @param y
     * @return
     */
    public static Complex[] cconvolve(Complex[] x, Complex[] y) {

        // should probably pad x and y with 0s so that they have same length and are powers of 2
        if (x.length != y.length) {
            throw new RuntimeException("Dimensions don't agree");
        }

        int n = x.length;

        // compute FFT of each sequence，求值
        Complex[] a = fft(x);
        Complex[] b = fft(y);

        // point-wise multiply，点值乘法
        Complex[] c = new Complex[n];
        for (int i = 0; i < n; i++) {
            c[i] = a[i].times(b[i]);
        }

        // compute inverse FFT，插值
        return ifft(c);
    }

    /**
     * compute the linear convolution of x and y
     *
     * @param x
     * @param y
     * @return
     */
    public static Complex[] convolve(Complex[] x, Complex[] y) {
        Complex zero = new Complex(0, 0);
        // 2n次数界，高阶系数为0.
        Complex[] a = new Complex[2 * x.length];
        for (int i = 0; i < x.length; i++) {
            a[i] = x[i];
        }
        for (int i = x.length; i < 2 * x.length; i++) {
            a[i] = zero;
        }

        Complex[] b = new Complex[2 * y.length];
        for (int i = 0; i < y.length; i++) {
            b[i] = y[i];
        }
        for (int i = y.length; i < 2 * y.length; i++) {
            b[i] = zero;
        }

        return cconvolve(a, b);
    }

    /**
     * Complex[] to double array for MusicPlayer
     *
     * @param x
     * @return
     */
    public static Double[] array(Complex[] x) {//for MusicPlayer
        int len = x.length;//修正幅过小 输出幅值 * 2 / length * 50
        return Stream.of(x).map(a -> a.abs() * 2 / len * 50).toArray(Double[]::new);
    }

    /**
     * display an array of Complex numbers to standard output
     *
     * @param x
     * @param title
     */
    public static void show(Double[] x, String... title) {
        for (String s : title) {
            System.out.print(s);
        }
        System.out.println();
        System.out.println("-------------------");
        for (int i = 0, len = x.length; i < len; i++) {
            System.out.println(x[i]);
        }
        System.out.println();
    }

    /**
     * display an array of Complex numbers to standard output
     *
     * @param x
     * @param title
     */
    public static void show(Complex[] x, String title) {
        System.out.println(title);
        System.out.println("-------------------");
        for (int i = 0, len = x.length; i < len; i++) {
            // 输出幅值需要 * 2 / length
            System.out.println(x[i].abs() * 2 / len);
        }
        System.out.println();
    }

    /**
     * 将数组数据重组成2的幂次方输出
     *
     * @param data
     * @return
     */
    public static Double[] pow2DoubleArr(Double[] data) {

        // 创建新数组
        Double[] newData = null;

        int dataLength = data.length;

        int sumNum = 2;
        while (sumNum < dataLength) {
            sumNum = sumNum * 2;
        }
        int addLength = sumNum - dataLength;

        if (addLength != 0) {
            newData = new Double[sumNum];
            System.arraycopy(data, 0, newData, 0, dataLength);
            for (int i = dataLength; i < sumNum; i++) {
                newData[i] = 0d;
            }
        } else {
            newData = data;
        }

        return newData;
    }

    /**
     * 去偏移量
     *
     * @param originalArr 原数组
     * @return 目标数组
     */
    public static Double[] deskew(Double[] originalArr) {
        // 过滤不正确的参数
        if (originalArr == null || originalArr.length <= 0) {
            return null;
        }

        // 定义目标数组
        Double[] resArr = new Double[originalArr.length];

        // 求数组总和
        Double sum = 0D;
        for (int i = 0; i < originalArr.length; i++) {
            sum += originalArr[i];
        }

        // 求数组平均值
        Double aver = sum / originalArr.length;

        // 去除偏移值
        for (int i = 0; i < originalArr.length; i++) {
            resArr[i] = originalArr[i] - aver;
        }

        return resArr;
    }

}

2.2 Complex.java

package com.xu.music.player.fft;

import java.util.Objects;

public class Complex {

    private final double re; // the real part
    private final double im; // the imaginary part

    // create a new object with the given real and imaginary parts
    public Complex(double real, double imag) {
        re = real;
        im = imag;
    }

    // a static version of plus
    public static Complex plus(Complex a, Complex b) {
        double real = a.re + b.re;
        double imag = a.im + b.im;
        Complex sum = new Complex(real, imag);
        return sum;
    }

    // sample client for testing
    public static void main(String[] args) {
        Complex a = new Complex(3.0, 4.0);
        Complex b = new Complex(-3.0, 4.0);

        System.out.println("a            = " + a);
        System.out.println("b            = " + b);
        System.out.println("Re(a)        = " + a.re());
        System.out.println("Im(a)        = " + a.im());
        System.out.println("b + a        = " + b.plus(a));
        System.out.println("a - b        = " + a.minus(b));
        System.out.println("a * b        = " + a.times(b));
        System.out.println("b * a        = " + b.times(a));
        System.out.println("a / b        = " + a.divides(b));
        System.out.println("(a / b) * b  = " + a.divides(b).times(b));
        System.out.println("conj(a)      = " + a.conjugate());
        System.out.println("|a|          = " + a.abs());
        System.out.println("tan(a)       = " + a.tan());
    }

    // return a string representation of the invoking Complex object
    @Override
    public String toString() {
        if (im == 0) {
            return re + "";
        }
        if (re == 0) {
            return im + "i";
        }
        if (im < 0) {
            return re + " - " + (-im) + "i";
        }
        return re + " + " + im + "i";
    }

    // return abs/modulus/magnitude
    public double abs() {
        return Math.hypot(re, im);
    }

    // return angle/phase/argument, normalized to be between -pi and pi
    public double phase() {
        return Math.atan2(im, re);
    }

    // return a new Complex object whose value is (this + b)
    public Complex plus(Complex b) {
        Complex a = this; // invoking object
        double real = a.re + b.re;
        double imag = a.im + b.im;
        return new Complex(real, imag);
    }

    // return a new Complex object whose value is (this - b)
    public Complex minus(Complex b) {
        Complex a = this;
        double real = a.re - b.re;
        double imag = a.im - b.im;
        return new Complex(real, imag);
    }

    // return a new Complex object whose value is (this * b)
    public Complex times(Complex b) {
        Complex a = this;
        double real = a.re * b.re - a.im * b.im;
        double imag = a.re * b.im + a.im * b.re;
        return new Complex(real, imag);
    }

    // return a new object whose value is (this * alpha)
    public Complex scale(double alpha) {
        return new Complex(alpha * re, alpha * im);
    }

    // return a new Complex object whose value is the conjugate of this
    public Complex conjugate() {
        return new Complex(re, -im);
    }

    // return a new Complex object whose value is the reciprocal of this
    public Complex reciprocal() {
        double scale = re * re + im * im;
        return new Complex(re / scale, -im / scale);
    }

    // return the real or imaginary part
    public double re() {
        return re;
    }

    public double im() {
        return im;
    }

    // return a / b
    public Complex divides(Complex b) {
        Complex a = this;
        return a.times(b.reciprocal());
    }

    // return a new Complex object whose value is the complex exponential of
    // this
    public Complex exp() {
        return new Complex(Math.exp(re) * Math.cos(im), Math.exp(re) * Math.sin(im));
    }

    // return a new Complex object whose value is the complex sine of this
    public Complex sin() {
        return new Complex(Math.sin(re) * Math.cosh(im), Math.cos(re) * Math.sinh(im));
    }

    // return a new Complex object whose value is the complex cosine of this
    public Complex cos() {
        return new Complex(Math.cos(re) * Math.cosh(im), -Math.sin(re) * Math.sinh(im));
    }

    // return a new Complex object whose value is the complex tangent of this
    public Complex tan() {
        return sin().divides(cos());
    }

    // See Section 3.3.
    @Override
    public boolean equals(Object x) {
        if (x == null) {
            return false;
        }
        if (this.getClass() != x.getClass()) {
            return false;
        }
        Complex that = (Complex) x;
        return (this.re == that.re) && (this.im == that.im);
    }

    // See Section 3.3.
    @Override
    public int hashCode() {
        return Objects.hash(re, im);
    }
}

3 音频播放

3.1 Player.java

package com.xu.music.player.player;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioFormat.Encoding;
import javax.sound.sampled.AudioInputStream;

import java.io.File;
import java.net.URL;

/**
 * Java 音频播放
 *
 * @author hyacinth
 * @date 2019年10月31日19:06:39
 */
public interface Player {

    /**
     * Java Music 加载音频
     *
     * @param url 音频文件url
     * @throws Exception 异常
     * @date 2019年10月31日19:06:39
     */
    void load(URL url) throws Exception;

    /**
     * Java Music 加载音频
     *
     * @param file 音频文件
     * @throws Exception 异常
     * @date 2019年10月31日19:06:39
     */
    void load(File file) throws Exception;

    /**
     * Java Music 加载音频
     *
     * @param path 文件路径
     * @throws Exception 异常
     * @date 2019年10月31日19:06:39
     */
    void load(String path) throws Exception;

    /**
     * Java Music 加载音频
     *
     * @param stream 音频文件输入流
     * @throws Exception 异常
     * @date 2019年10月31日19:06:39
     */
    void load(AudioInputStream stream) throws Exception;

    /**
     * Java Music 加载音频
     *
     * @param encoding Encoding
     * @param stream   AudioInputStream
     * @throws Exception 异常
     * @date 2019年10月31日19:06:39
     */
    void load(Encoding encoding, AudioInputStream stream) throws Exception;

    /**
     * Java Music 加载音频
     *
     * @param format AudioFormat
     * @param stream AudioInputStream
     * @throws Exception 异常
     * @date 2019年10月31日19:06:39
     */
    void load(AudioFormat format, AudioInputStream stream) throws Exception;

    /**
     * Java Music 暂停播放
     *
     * @date 2019年10月31日19:06:39
     */
    void pause();

    /**
     * Java Music 继续播放
     *
     * @date 2019年10月31日19:06:39
     */
    void resume();

    /**
     * Java Music 开始播放
     *
     * @throws Exception 异常
     * @date 2019年10月31日19:06:39
     */
    void play() throws Exception;

    /**
     * Java Music 结束播放
     *
     * @description: Java Music 结束播放
     * @date 2019年10月31日19:06:39
     */
    void stop();

}

3.1 XPlayer.java

package com.xu.music.player.player;

import cn.hutool.core.io.IoUtil;
import cn.hutool.core.text.CharSequenceUtil;
import javazoom.spi.mpeg.sampled.file.MpegAudioFileReader;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.DataLine;
import javax.sound.sampled.SourceDataLine;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.LinkedList;

/**
 * Java 音频播放
 *
 * @author hyacinth
 * @date 2019年10月31日19:06:39
 */
public class XPlayer implements Player {

    private static SourceDataLine data = null;

    private static AudioInputStream audio = null;

    public static volatile LinkedList<Double> deque = new LinkedList<>();

    public void put(Double v) {
        synchronized (deque) {
            deque.add(Math.abs(v));
            if (deque.size() > 90) {
                deque.removeFirst();
            }
        }
    }

    private XPlayer() {

    }

    public static XPlayer createPlayer() {
        return XPlayer.SingletonHolder.player;
    }

    private static class SingletonHolder {
        private static final XPlayer player = new XPlayer();
    }

    @Override
    public void load(URL url) throws Exception {
        load(AudioSystem.getAudioInputStream(url));
    }

    @Override
    public void load(File file) throws Exception {
        String name = file.getName();
        if (CharSequenceUtil.endWithIgnoreCase(name, ".mp3")) {
            AudioInputStream stream = new MpegAudioFileReader().getAudioInputStream(file);

            AudioFormat format = stream.getFormat();
            format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED, format.getSampleRate(), 16, format.getChannels(),
                    format.getChannels() * 2, format.getSampleRate(), false);

            stream = AudioSystem.getAudioInputStream(format, stream);
            load(stream);
        } else if (CharSequenceUtil.endWithIgnoreCase(name, ".flac")) {
            AudioInputStream stream = AudioSystem.getAudioInputStream(file);

            AudioFormat format = stream.getFormat();
            format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED, format.getSampleRate(), 16, format.getChannels(),
                    format.getChannels() * 2, format.getSampleRate(), false);

            stream = AudioSystem.getAudioInputStream(format, stream);

            load(stream);
        } else {
            load(AudioSystem.getAudioInputStream(file));
        }
    }

    @Override
    public void load(String path) throws Exception {
        load(new File(path));
    }

    @Override
    public void load(AudioInputStream stream) throws Exception {
        DataLine.Info info = new DataLine.Info(SourceDataLine.class, stream.getFormat(), AudioSystem.NOT_SPECIFIED);
        data = (SourceDataLine) AudioSystem.getLine(info);
        data.open(stream.getFormat());
        audio = stream;
    }

    @Override
    public void load(AudioFormat.Encoding encoding, AudioInputStream stream) throws Exception {
        load(AudioSystem.getAudioInputStream(encoding, stream));
    }

    @Override
    public void load(AudioFormat format, AudioInputStream stream) throws Exception {
        load(AudioSystem.getAudioInputStream(format, stream));
    }

    @Override
    public void pause() {

    }

    @Override
    public void resume() {

    }

    @Override
    public void play() throws IOException {
        if (null == audio || null == data) {
            return;
        }
        data.start();
        byte[] buf = new byte[4];
        int channels = audio.getFormat().getChannels();
        float rate = audio.getFormat().getSampleRate();
        while (audio.read(buf) != -1) {
            if (channels == 2) {//立体声
                if (rate == 16) {
                    put((double) ((buf[1] << 8) | buf[0]));//左声道
                    //put((double) ((buf[3] << 8) | buf[2]));//右声道
                } else {
                    put((double) buf[1]);//左声道
                    put((double) buf[3]);//左声道
                    //put((double) buf[2]);//右声道
                    //put((double) buf[4]);//右声道
                }
            } else {//单声道
                if (rate == 16) {
                    put((double) ((buf[1] << 8) | buf[0]));
                    put((double) ((buf[3] << 8) | buf[2]));
                } else {
                    put((double) buf[0]);
                    put((double) buf[1]);
                    put((double) buf[2]);
                    put((double) buf[3]);
                }
            }
            data.write(buf, 0, 4);
        }
    }

    @Override
    public void stop() {
        if (null == audio || null == data) {
            return;
        }
        IoUtil.close(audio);
        data.stop();
        IoUtil.close(data);
    }

}

4 Java SWT 显示频谱

package com.xu.music.player.test;

import cn.hutool.core.collection.CollUtil;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

import java.io.File;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;

import com.xu.music.player.fft.Complex;
import com.xu.music.player.fft.FFT;
import com.xu.music.player.player.Player;
import com.xu.music.player.player.XPlayer;

/**
 * SWT Composite 绘画
 *
 * @date 2024年2月2日19点27分
 * @since V1.0.0.0
 */
public class SwtDraw {

    private Shell shell = null;

    private Display display = null;

    private Composite composite = null;

    private final Random random = new Random();

    private final List<Integer> spectrum = new LinkedList<>();

    public static void main(String[] args) {
        SwtDraw test = new SwtDraw();
        test.open();
    }

    /**
     * 测试播放
     */
    public void play() {
        try {
            Player player = XPlayer.createPlayer();
            player.load(new File("D:\\Kugou\\梦涵 - 加减乘除.mp3"));
            new Thread(() -> {
                try {
                    player.play();
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            }).start();
        } catch (Exception e) {

        }
    }

    /**
     * 打开 SWT 界面
     *
     * @date 2024年2月2日19点27分
     * @since V1.0.0.0
     */
    public void open() {
        display = Display.getDefault();
        createContents();
        shell.open();
        shell.layout();
        play();
        task();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
    }

    /**
     * 设置 SWT Shell内容
     *
     * @date 2024年2月2日19点27分
     * @since V1.0.0.0
     */
    protected void createContents() {
        shell = new Shell(display);
        shell.setSize(900, 500);
        shell.setLayout(new FillLayout(SWT.HORIZONTAL));

        // 创建一个Composite
        composite = new Composite(shell, SWT.NONE);

        // 添加绘图监听器
        composite.addPaintListener(listener -> {
            GC gc = listener.gc;

            int width = listener.width;
            int height = listener.height;
            int length = width / 25;

            if (spectrum.size() >= length) {
                for (int i = 0; i < length; i++) {
                    draw(gc, i * 25, height, 25, spectrum.get(i));
                }
            }

        });

    }

    /**
     * 模拟 需要绘画的数据 任务
     *
     * @date 2024年2月2日19点27分
     * @since V1.0.0.0
     */
    public void task() {
        Timer timer = new Timer(true);
        timer.scheduleAtFixedRate(new TimerTask() {
            @Override
            public void run() {
                display.asyncExec(() -> {
                    if (!composite.isDisposed()) {
                        // 在这里调用你更新数据的方法
                        updateData();
                        // 重绘
                        composite.redraw();
                    }
                });
            }
        }, 0, 100);
    }

    /**
     * 模拟 更新绘画的数据
     *
     * @date 2024年2月2日19点27分
     * @since V1.0.0.0
     */
    public void updateData() {
        spectrum.clear();
        if (CollUtil.isEmpty(XPlayer.deque)) {
            return;
        }

        Complex[] x = new Complex[XPlayer.deque.size()];
        for (int i = 0; i < x.length; i++) {
            try {
                x[i] = new Complex(XPlayer.deque.get(i), 0);
            } catch (Exception e) {
                x[i] = new Complex(0, 0);
            }
        }

        Double[] value = FFT.array(x);
        for (double v : value) {
            spectrum.add((int) v);
        }

    }

    /**
     * Composite 绘画
     *
     * @param gc     GC
     * @param x      x坐标
     * @param y      y坐标
     * @param width  宽度
     * @param height 高度
     * @date 2024年2月2日19点27分
     * @since V1.0.0.0
     */
    private void draw(GC gc, int x, int y, int width, int height) {
        // 设置条形的颜色
        Color color = new Color(display, random.nextInt(255), random.nextInt(255), random.nextInt(255));
        gc.setBackground(color);
        // 绘制条形
        Rectangle draw = new Rectangle(x, y, width, -height);
        gc.fillRectangle(draw);
        // 释放颜色资源
        color. Dispose();
    }

}

5 结果