package com.longneo.downloader;import java.awt.*;import java.awt.event.*;import java.io.FileOutputStream;import java.io.InputStream;import java.net.URL;import java.net.URLConnection;import javax.swing.*;public class Downloader {		private Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();		private final JFrame fm = new JFrame();	private final JPanel panel = new JPanel();    private final JLabel label1 = new JLabel("网络资源的下载 ");    private final JLabel label2 = new JLabel("网络资源地址：");    private final Al al = new Al();        JButton StartButton = new JButton("开始下载");    JButton resetButton = new JButton("清空");    JButton exitButton = new JButton("退出");    JTextField urlField = new JTextField(20);	public void init(){		panel.setLayout(new FlowLayout());        label1.setFont(new Font("雅黑", Font.BOLD, 15));        panel.add(label1);        panel.add(label2);        panel.add(urlField);        panel.add(StartButton);        panel.add(resetButton);        panel.add(exitButton);                fm.setContentPane(panel);                StartButton.addActionListener(al);        resetButton.addActionListener(al);        exitButton.addActionListener(al);                fm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        fm.setSize(400, 200);        fm.setResizable(true);        fm.setLocation((screenSize.width-fm.getWidth())/2,(screenSize.height-fm.getHeight())/2);        fm.setVisible(true);	}		public class Al implements ActionListener{				@Override	    public void actionPerformed(ActionEvent e){	        if(e.getSource() == StartButton){	            if("".equals(urlField.getText())){	                JOptionPane.showMessageDialog(fm, "请输入资源地址");	                return;	            }	            String url = urlField.getText();	            try{	                download(url);	            }catch(Exception e1){	                JOptionPane.showMessageDialog(fm, "地址有误，请检查，谢谢！");	                e1.printStackTrace();	            }	        }else if(e.getSource() == resetButton){	            urlField.setText("");	        }else{	            System.exit(0);	        }	    }	}		public void download(String address) throws Exception{        URL url = new URL(address);        URLConnection urlcon = url.openConnection();        urlcon.connect();        InputStream in = urlcon.getInputStream();        String filePath = url.getFile();        int pos = filePath.lastIndexOf("/");        String fileName = filePath.substring(pos + 1);        FileOutputStream out = new FileOutputStream("F:\\" + fileName);        byte[] bytes = new byte[1024];        int len = in.read();        while(len != -1){            out.write(bytes, 0, len);            len = in.read();        }        out.close();        in.close();        JOptionPane.showMessageDialog(fm, "下载完毕");    }	}