大多正式一点的Java源代码，在头部都设有头注释信息，其中包含一些版权声明等信息。例如JDK的源码一般如下：
/*
* @(#)Object.java 1.61 03/01/23
*
* Copyright 2003 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.lang;
public class Object { .....}
如果我们有个小工具能把我们项目里所有目录下的Java代码统一设置头注释就好了；比如当版本信息等改变时，只要重新运行一下即可一次性更新。下面我们就来亲自写一个。
思路很简单：
建立一个窗口，用户可以设置一个目录、编写头注释信息；
查找目录下所有子文件，如果是Java文件则处理之，如果是目录则递归处理；
处理Java文件时，打开后，找到package语句或者第一个import语句，作为注释的插入点，插入注释；
将增加了头注释的文件内容写回文件。
本例中判断头注释插入点的逻辑比较简单，只是根据package语句或者第一个import语句来判断注释插入点，尚不严谨（比如原有的头注释中可能包含这些关键字），仅供参考。
源码如下：
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class HeaderCommentsGenerator {
private static int count = 0;
public static void main(String[] args) {
final JFrame frame = new JFrame("HeaderCommentsGenerator 1.0 [xiaozhonghua@hotmail.com]");
JPanel contentPane = (JPanel) frame.getContentPane();
JPanel centerPane = new JPanel(new BorderLayout(10, 10));
centerPane.setBorder(BorderFactory.createEmptyBorder(10, 10, 0, 10));
JPanel pathPane = new JPanel(new BorderLayout());
final JTextField txtPath = new JTextField();
txtPath.setText("Please select your file or path.");
pathPane.add(txtPath, BorderLayout.CENTER);
JButton btnSelectPath = new JButton("Browser...");
btnSelectPath.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JFileChooser chooser = new JFileChooser();
chooser.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
int returnVal = chooser.showOpenDialog(frame);
if (returnVal == JFileChooser.APPROVE_OPTION) {
txtPath.setText(chooser.getSelectedFile().getAbsolutePath());
}
}
});
btnSelectPath.setMnemonic('B');
pathPane.add(btnSelectPath, BorderLayout.EAST);
centerPane.add(pathPane, BorderLayout.NORTH);
final JTextArea txtComments = new JTextArea();
txtComments.setText("/*\n" +
" * Copyright 2003-2004 ABC Software, Inc. All rights reserved.\n" +
" */");
centerPane.add(new JScrollPane(txtComments), BorderLayout.CENTER);
contentPane.add(centerPane, BorderLayout.CENTER);
JPanel buttonPane = new JPanel(new FlowLayout(FlowLayout.RIGHT, 10, 10));
JButton btnOK = new JButton("Generate!");
btnOK.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String path = txtPath.getText();
File file = new File(path);
if (!file.exists()) {
JOptionPane.showMessageDialog(frame,
"Path '" + path + "' not exist.",
"Error",
JOptionPane.ERROR_MESSAGE);
} else {
commentFile(file, txtComments.getText());
JOptionPane.showMessageDialog(frame,
"Finish, total " + count + " files are processed.",
"Information",
JOptionPane.INFORMATION_MESSAGE);
}
}
});
btnOK.setMnemonic('G');
JButton btnClose = new JButton("Close");
btnClose.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
btnClose.setMnemonic('C');
buttonPane.add(btnOK);
buttonPane.add(btnClose);
contentPane.add(buttonPane, BorderLayout.SOUTH);
frame.setSize(500, 300);
frame.show();
}
private static void commentFile(File file, String comments) {
if (file != null && file.exists()) {
if (file.isDirectory()) {
String[] children = file.list();
for (int i = 0; i < children.length; i++) {
File child = new File(file.getPath() + System.getProperty("file.separator") + children[i]);
commentFile(child, comments);
}
} else {
if (file.getName().toLowerCase().endsWith(".java")) {
System.out.println(file.getName());
count++;
try {
RandomAccessFile raFile = new RandomAccessFile(file, "rw");
byte[] content = new byte[ (int) raFile.length()];
raFile.readFully(content);
String all = new String(content);
all = all.trim();
while (all.startsWith("\n")) {
all = all.substring(1);
}
if (all.indexOf("package") != -1) {
all = all.substring(all.indexOf("package"));
}
if (all.indexOf("import") != -1) {
all = all.substring(all.indexOf("package"));
}
all = comments + "\n" + all;
raFile.close();
FileWriter writer = new FileWriter(file);
writer.write(all);
writer.close();
}
catch (Exception ex) {
ex.printStackTrace();
}
}
}
}
}
}
希望这个小工具对你有点用处。