Java Swing 多線程加載圖片（保證順序一致）

大二的時候做的課程設計，圖片管理器，當時遇到圖片很多的文件夾，加載順序非常慢。雖然嘗試用多個Thread加載圖片，卻無法保證圖片按順序加載。直到今天學會了使用Callable接口和Future接口，於是心血來潮實現了這個功能。

廢話不多說，看代碼。

多線程加載圖片（核心）：

 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; } //線程池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; } }); //並發加載圖片，並使用Future保存加載結果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); } //等待所有並發加載返回結果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 進行排序List<JLabel> sortedList = images.stream().sorted().collect(Collectors.toList()); return sortedList; } //繼承JLabel並實現Comparable接口，從而對JLabel進行排序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生成縮略圖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; } }}

Swing界面：

 package com.lin.imagemgr;import java.awt.BorderLayout;import java.awt.Dimension;import java.awt.FlowLayout;import java.util.List;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.JScrollPane;import javax.swing.JTextField;public class MainFrame extends JFrame{ private static final long serialVersionUID = 1L; private JTextField pathField; private JButton showBtn; private JPanel contentPanel; public void init() { JPanel topPanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 5, 0)); topPanel.setPreferredSize(new Dimension(800, 40)); pathField = new JTextField(50); showBtn = new JButton("顯示圖片"); topPanel.add(pathField); topPanel.add(showBtn); getContentPane().add(BorderLayout.NORTH, topPanel); contentPanel = new JPanel(); contentPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5)); contentPanel.setPreferredSize(new Dimension(750, 1800)); JScrollPane jsp = new JScrollPane(contentPanel); getContentPane().add(BorderLayout.CENTER, jsp); showBtn.addActionListener((e) -> { try { loadImages(); } catch (Exception ex) { ex.printStackTrace(); } }); setSize(800, 650); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setLocationRelativeTo(null); setVisible(true); } public void loadImages() { contentPanel.removeAll(); String path = pathField.getText(); long start = System.currentTimeMillis(); List<JLabel> images = ImageMgr.getInstance().loadImages(path); for (JLabel label :images) { contentPanel.add(label); } contentPanel.updateUI(); long end = System.currentTimeMillis(); System.out.println("加載需要" + (end - start) + "毫秒！"); } public static void main(String[] args) { new MainFrame().init(); }}

運行結果

在我的電腦上，加載92張圖片並渲染到界面上，總共花了1568毫秒。大家可以找一個圖片很多的文件夾，嘗試加載大量圖片的情況。

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。