Java技巧：java实现文件监控技巧分享

java本身不能直接监听系统的文件操作事件，不过可以先编写C/C++调用操作系统的API监听文件，再通过jni调用的方式实现。限于本人的C/C++水平有限，没有用C/C++实现该接口，而且已有开源组件JNotify实现了这个功能，本文例子使用JNotify。

public class MainFrame extends JFrame ...{

    private JPanel contentPane;
    private JTextField textField;
    private JTextArea textArea;

    public static void main(String[] args) ...{
        EventQueue.invokeLater(new Runnable() ...{
            public void run() ...{
                try ...{
                    MainFrame frame = new MainFrame();
                    frame.setVisible(true);
                } catch (Exception e) ...{
                    e.printStackTrace();
                }
            }
        });
    }

    public MainFrame() ...{
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 543, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JLabel label = new JLabel("监控路径：");
        label.setBounds(33, 20, 65, 15);
        contentPane.add(label);

        textField = new JTextField("D:/");
        textField.setBounds(90, 16, 219, 21);
        contentPane.add(textField);
        textField.setColumns(10);

        JButton button = new JButton("开始监控");
        button.addActionListener(new ActionListener() ...{
            public void actionPerformed(ActionEvent e) ...{
                try ...{
                    addWatch();
                } catch (Exception ex) ...{
                    ex.printStackTrace();
                }
            }
        });
        button.setBounds(319, 16, 93, 23);
        contentPane.add(button);

        textArea = new JTextArea();
        JScrollPane scrollPane = new JScrollPane(textArea);
        scrollPane.setBounds(33, 45, 480, 207);
        contentPane.add(scrollPane);
    }

    public void addWatch() throws Exception ...{
        String path = textField.getText();
        int mask = JNotify.FILE_CREATED | JNotify.FILE_DELETED
                | JNotify.FILE_MODIFIED | JNotify.FILE_RENAMED;
        boolean watchSubtree = true;
        //添加文件监听
        int watchID = JNotify.addWatch(path, mask, watchSubtree, new Listener());
    }

    class Listener implements JNotifyListener ...{
        public void fileRenamed(int wd, String rootPath, String oldName,
                String newName) ...{
            textArea.append("文件：" + rootPath + " : " + oldName + " 重命名为： "
                    + newName + "/n");
        }

        public void fileModified(int wd, String rootPath, String name) ...{
            textArea.append("文件修改 " + rootPath + " : " + name + "/n");
        }

        public void fileDeleted(int wd, String rootPath, String name) ...{
            textArea.append("删除文件： " + rootPath + " : " + name + "/n");
        }

        public void fileCreated(int wd, String rootPath, String name) ...{
            textArea.append("新建文件: " + rootPath + " : " + name + "/n");
        }
    }
}
 　　运行效果：在D盘新建一个文件和修改文件名操作。