在《JAVA核心编程》中，有一段这样的代码

import javax.swing.*; import java.awt.*; import java.io.File; public class ImageViewer { public static void main(String[] args){ EventQueue.invokeLater(() -> { JFrame frame = new ImageViewerFrame(); frame.setTitle("ImageViewer"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); }); } } class ImageViewerFrame extends JFrame{ private JLabel label; private JFileChooser chooser; private static final int DEFAULT_WIDTH = 300; private static final int DEFAULT_HEIGHT = 400; public ImageViewerFrame(){ setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT); label = new JLabel(); add(label); chooser = new JFileChooser(); chooser.setCurrentDirectory(new File(".")); JMenuBar menuBar = new JMenuBar(); setJMenuBar(menuBar); JMenu menu = new JMenu(); menuBar.add(menu); JMenuItem openItem = new JMenuItem("open"); menu.add(openItem); openItem.addActionListener(Event -> { int result = chooser.showOpenDialog(null); if (result == JFileChooser.APPROVE_OPTION){ String name = chooser.getSelectedFile().getPath(); label.setIcon(new ImageIcon(name)); } }); JMenuItem exitItem = new JMenuItem("exit"); menu.add(exitItem); exitItem.addActionListener(Event -> System.exit(0)); } }

可以看到两处这样的代码

() -> { JFrame frame = new ImageViewerFrame(); frame.setTitle("ImageViewer"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); }

Event -> { int result = chooser.showOpenDialog(null); if (result == JFileChooser.APPROVE_OPTION){ String name = chooser.getSelectedFile().getPath(); label.setIcon(new ImageIcon(name)); }

不知道->这个符号是什么意思，百度了一下，也没有查到