小编Joh*_*ohn的帖子

我正在制作一个桌面应用程序,它有一个JFileChooser(ShowSaveDialog)函数..当我试图保存一个示例文本文件时,程序没有得到我选择的扩展文件..我正在尝试使用if else或switch语句和我无法弄清楚如果选择pdf,word或txt扩展名作为文件扩展名,我将使用什么命令来获取条件的字符串/ Int值...

public class Save {
    static boolean flag = false;
    public static void main(String[] args) throws IOException, SQLException {
        JFileChooser saveFile = new JFileChooser();
        saveFile.setDialogTitle("Save as"); 

        FileNameExtensionFilter File_ext_txt =
            new FileNameExtensionFilter("Text Documents(*.txt)", "txt");
        FileNameExtensionFilter File_ext_pdf =
            new FileNameExtensionFilter("PDF", "pdf");
        FileNameExtensionFilter File_ext_doc =
            new FileNameExtensionFilter("Word 97-2003 Document", "doc");
        saveFile.addChoosableFileFilter(File_ext_pdf);
        saveFile.addChoosableFileFilter(File_ext_doc);
        saveFile.addChoosableFileFilter(File_ext_txt);

        FileFilter extension = saveFile.getFileFilter();
        int userSelection = saveFile.showSaveDialog(null);
        File File_Path = saveFile.getSelectedFile();
        String fullPath = File_Path.getAbsolutePath();
        String Ext = null;
        if (userSelection == JFileChooser.APPROVE_OPTION){
            if(extension == File_ext_txt){
                Ext …