哈哈。。引用a276202460的发言，感谢的是冰封。。

哦 也感谢大家

呵呵，没代码呀？
把你的转换核心代码贴上来我们大家批判一下～哈哈哈哈

支持

好的啊 没问题 大家一定要指点哦 不要光“顶”

package swing;

import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.SystemColor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
import javax.swing.UIManager;
public class Temp extends JFrame {
    private ButtonGroup buttonGroup = new ButtonGroup();
    private static Temp frame;
    
    public static void main(String args[]) {
        frame = new Temp();
        frame.setTitle(\"大小写转换工具\");
        frame.setVisible(true);
    }
    public Temp() {
        getContentPane().setLayout(null);
        setBounds(100, 100, 500, 375);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        final JPanel panel = new JPanel();
        panel.setBackground(SystemColor.activeCaptionBorder);
        panel.setLayout(null);
        panel.setBounds(64, 59, 371, 272);
        getContentPane().add(panel);
        final JLabel label = new JLabel();
        label.setBounds(22, 48, 71, 15);
        label.setText(\"来源路径：\");
        panel.add(label);
        final JLabel label_1 = new JLabel();
        label_1.setText(\"目标路径：\");
        label_1.setBounds(22, 98, 71, 15);
        panel.add(label_1);
        final JTextField textField = new JTextField();
        textField.setBounds(99, 45, 161, 21);
        panel.add(textField);
        final JTextField textField_1 = new JTextField();
        textField_1.setBounds(99, 95, 161, 21);
        panel.add(textField_1);
        final JButton button = new JButton();
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                JFileChooser chooser = new JFileChooser();
                int returnVal = chooser.showOpenDialog(button);
                if(returnVal == chooser.APPROVE_OPTION){
                    File file = chooser.getSelectedFile();
                    textField.setText(file.getAbsolutePath());
                }
                
            }
        });
        button.setText(\"选择\");
        button.setBounds(266, 44, 99, 23);
        panel.add(button);
        final JButton button_1 = new JButton();
        button_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                JFileChooser chooser = new JFileChooser();
                int returnVal = chooser.showSaveDialog(button);
                if(returnVal == chooser.APPROVE_OPTION){
                    File file = chooser.getSelectedFile();
                    textField_1.setText(file.getAbsolutePath());
                }
                
            }
        });
        button_1.setText(\"选择\");
        button_1.setBounds(266, 94, 99, 23);
        panel.add(button_1);
        final JRadioButton radioButton = new JRadioButton();
        radioButton.setSelected(true);
        radioButton.setBackground(SystemColor.activeCaptionBorder);
        buttonGroup.add(radioButton);
        radioButton.setText(\"小写转大写\");
        radioButton.setBounds(48, 143, 121, 23);
        panel.add(radioButton);
        final JRadioButton radioButton_1 = new JRadioButton();
        radioButton_1.setBackground(SystemColor.activeCaptionBorder);
        buttonGroup.add(radioButton_1);
        radioButton_1.setText(\"大写转小写\");
        radioButton_1.setBounds(225, 143, 121, 23);
        panel.add(radioButton_1);
        final JButton button_2 = new JButton();
        button_2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String path1 = textField.getText();
                String path2 = textField_1.getText();
                try {
                    if(radioButton.isSelected()){
                        TransitionToUpper(path1, path2);
                        ShowDialog(\"转换成功！\",\"成功\");
                    }else if(radioButton_1.isSelected()){
                        TransitionToLower(path1, path2);
                        ShowDialog(\"转换成功！\",\"成功\");
                    }
                } catch (IOException e1) {
                    ShowDialog(\"转换失败！\",\"失败\");
                }
            }
            
            private void ShowDialog(String str1,String str2) {
                final JDialog dialog = new JDialog(frame, str2);
                dialog.setSize(180, 80);
                JLabel label = new JLabel(str1);
                dialog.setLayout(new FlowLayout());
                dialog.add(label);
                dialog.setLocation(420, 250);
                dialog.setVisible(true);
            }
            
        });
        
        button_2.setText(\"转换开始\");
        button_2.setBounds(132, 211, 99, 23);
        panel.add(button_2);
        final JLabel label_2 = new JLabel();
        label_2.setFont(new Font(\"\", Font.BOLD, 26));
        label_2.setText(\"大小写转换\");
        label_2.setBounds(174, 23, 144, 30);
        getContentPane().add(label_2);
        getContentPane().setBackground(SystemColor.activeCaptionBorder);
    }
    public void TransitionToUpper(String path1, String path2) throws IOException {
        String tmp = null;
        BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(path1)));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(path2)));
        while ((tmp = br.readLine()) != null) {
            String tmp1 = tmp.toUpperCase();
            bw.write(tmp1 + \"\n\");
            bw.flush();
        }
        br.close();
        bw.close();
    }
    
    public void TransitionToLower(String path1, String path2) throws IOException {
        String tmp = null;
        BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(path1)));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(path2)));
        while ((tmp = br.readLine()) != null) {
            String tmp1 = tmp.toLowerCase();
            bw.write(tmp1 + \"\n\");
            bw.flush();
        }
        br.close();
        bw.close();
    }
}

我顶

楼上的注意了！

需要更正的地方

一、动态变量调用静态方法／变量产生歧义
if (returnVal == chooser.APPROVE_OPTION) {
File file = chooser.getSelectedFile();
textField.setText(file.getAbsolutePath());
}

因为 chooser.APPROVE_OPTION;是一个静态的变量，所以最好不要用动态的变量去获取它，以避免歧义，让别人阅读代码时误认为是普通的方法/变量。

更改为：

if (returnVal == JFileChooser.APPROVE_OPTION) {
File file = chooser.getSelectedFile();
textField.setText(file.getAbsolutePath());
}

以下其他地方同理...


二、变量命名混乱
label_1、button_1、button_2大量无意义的变量名充斥其中，根本看不明白那个是那个

三、布局方式混乱
radioButton_1.setBounds(225, 143, 121, 23);
既然Java有布局管理，就不应该要你来操这个心。否则你会丧失JAVA的SWING编程最大的优势：控件随着窗体的改变而改变。不相信你拉拉你的窗体看看就知道了。

还有其他的，你先能改正这些再说吧

还有就是GUI中的MVC设计模式
具体可以看看我的这个帖子
http://bbs.bc-cn.net/viewthread.php?tid=164297&extra=&page=10#291555