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。