Java Swing 多线程加载图片（保证顺序一致）

package com.lin.imagemgr;import java.awt.Dimension;import java.awt.image.BufferedImage;import java.io.File;import java.io.FilenameFilter;import java.io.IOException;import java.util.ArrayList;import java.util.List;import java.util.concurrent.ExecutionException;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.Future;import java.util.stream.Collectors;import javax.swing.ImageIcon;import javax.swing.JLabel;import net.coobird.thumbnailator.Thumbnails;public class ImageMgr { private static ImageMgr instance = new ImageMgr(); private ImageMgr() {} public static ImageMgr getInstance() {  return instance; } //线程池 private ExecutorService executor = Executors.newFixedThreadPool(8); public List<JLabel> loadImages(String path) {  List<JLabel> images = new ArrayList<>();  File file = new File(path);  if (!file.isDirectory()) {   throw new RuntimeException("need directory!");  }  File[] files = file.listFiles(new FilenameFilter() {   @Override   public boolean accept(File dir, String name) {    //thumbnail只支持jpg??    if (name.endsWith(".jpg")) {     return true;    }    return false;   }  });  //并发加载图片，并使用Future保存加载结果  List<Future<MyLabel>> futures = new ArrayList<>();  for (final File f : files) {   Future<MyLabel> future = executor.submit(() -> {    return new MyLabel(f.getName(), f.getAbsolutePath());   });   futures.add(future);  }  //等待所有并发加载返回结果  try {   for (Future<MyLabel> future : futures) {    MyLabel icon = future.get();    images.add(icon);   }  } catch (InterruptedException e) {   e.printStackTrace();  } catch (ExecutionException e) {   e.printStackTrace();  }  //Java8使用stream API 进行排序  List<JLabel> sortedList = images.stream().sorted().collect(Collectors.toList());  return sortedList; } //继承JLabel并实现Comparable接口，从而对JLabel进行排序 private static class MyLabel extends JLabel implements Comparable<MyLabel>{  private static final long serialVersionUID = 1L;  private String fileName;  public MyLabel(String fileName, String fullPath) {   this.fileName = fileName;   //使用thumbnailator生成缩略图   try {    BufferedImage bufferedImage = Thumbnails.of(fullPath)     .size(100, 120)    .asBufferedImage();    setIcon(new ImageIcon(bufferedImage));    setPreferredSize(new Dimension(100, 120));   } catch (IOException e) {    e.printStackTrace();   }  }  @Override  public int compareTo(MyLabel o) {   int result = this.fileName.compareTo(o.fileName);   return result;  } }}