Java中Lambda表达式中“-＞“

                                 Java中Lambda表达式中"->" 

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));}

这就是Java8的lambda表达式。也即匿名函数。

上面那一段可以看成如下:

EventQueue.invokeLater(new Runnable() {public void run() {JFrame frame = new ImageViewerFrame();frame.setTitle("ImageViewer");frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.setVisible(true);}});

下面一段可以看成:

只不过java自动帮你翻译了一下。