//文件过滤器
import java.io.File;

import javax.swing.filechooser.FileFilter;

public class MyFilter extends FileFilter{

    private String[] filterString = null;

    public MyFilter(String[] filStrings){

        this.filterString = filStrings;

    }

    public boolean accept(File file){

           if(file.isDirectory()) return true;

           for(int i=0; i<filterString.length; ++i)

               if(file.getName().endsWith(filterString[i]))

                   return true;

           /* 返回要显示的文件类型 */

           /*

            *   File.isDirectory()测试此抽象路径名表示的文件是否是一个目录

           */

           return false;

      }

      public String getDescription() {

          String ss = "";

          for(int i=0; i<filterString.length; ++i)

              ss += " *" + filterString[i];

          return("Txt Files(" + ss + ")");                  //返回显示文件类型的描述

      }

}

//文件的选择
　　　　　　　　　　JFileChooser jfc = new JFileChooser();

                //设置文件的过滤器

                String[] filterString = {".cpp", ".c"};

                MyFilter filter = new MyFilter(filterString);

                //获取jar包位置，设置JFileChooser当前路径

                String jarFilePath = Main.class.getProtectionDomain().getCodeSource().getLocation().getFile();

                try {

                    jarFilePath = URLDecoder.decode(jarFilePath, "UTF-8");

                } catch (UnsupportedEncodingException ex) {

                    ex.printStackTrace();

                }

                jfc.setCurrentDirectory(new File(jarFilePath));

                jfc.setFileFilter(filter);

                jfc.showOpenDialog(null);

                File fl = jfc.getSelectedFile();

                if(fl != null){

                    String code = "";

                    try {

                        BufferedReader br = new BufferedReader(new FileReader(fl));

                        String newLine = null;

                        boolean flag = true;

                        while((newLine=br.readLine()) != null){

                        }

                    } catch (FileNotFoundException ex) {

                        ex.printStackTrace();

                    } catch (IOException ex) {

                        ex.printStackTrace();

                    }

                }

//文件的保存
　　　　　　　　　　　　JFileChooser jfc = new JFileChooser();

                    String[] filterString = {".txt"};

                    //设置文件的过滤器

                    MyFilter filter = new MyFilter(filterString);

                    //获取jar包位置，设置JFileChooser当前路径

                    String jarFilePath = LexicalAnalyzer.class.getProtectionDomain().getCodeSource().getLocation().getFile();

                    try {

                        jarFilePath = URLDecoder.decode(jarFilePath, "UTF-8");

                    } catch (UnsupportedEncodingException e) {

                        e.printStackTrace();

                    }

                    jfc.setCurrentDirectory(new File(jarFilePath));

                    jfc.setFileFilter(filter);

                    jfc.showSaveDialog(null);

                    File fl = jfc.getSelectedFile();

                    OutputStreamWriter osw;

                    try {

                        osw = new OutputStreamWriter(new FileOutputStream(fl));

                        String text = textPane.getText();

                        osw.write(text, 0, text.length());

                        osw.flush();

                        osw.close();

                    } catch (FileNotFoundException e) {

                        // TODO Auto-generated catch block

                        e.printStackTrace();

                    } catch (IOException e) {

                        // TODO Auto-generated catch block

                        e.printStackTrace();

                    }