如何实现文件的打开与保存对话框（JFileChooser）

 Java.swing.JFileChooser类可以显示文件打开和保存对话框

常用构造方法如下：

Public JFileChooser(File currentDirectory)

Public JFileChooser(FileSystemViem fav)

Public JFileChooser(File currentDirectory, FileSystemViem  fav )

其他方法：

Public int showOpenDialog(Component parent) throws HeadlessException:显示打开对话框

Public int showSaveDialog(Component parent) throws HeadlessException:显示保存对话框

Public void setFileFilter(FileFilter filter):设置过滤器

Public File getSelectedFile();得到被选中的文件

 

package例30_使用JFileChooser显示文件的打开对话框和保存对话框;

 

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

 

import javax.swing.JButton;

import javax.swing.JFileChooser;

import javax.swing.JFrame;

import javax.swing.JOptionPane;

import javax.swing.JPanel;

import javax.swing.filechooser.FileNameExtensionFilter;

 

publicclass JFileChooserDemoextends JFrame{

 

   /**

    *

    */

   privatestaticfinallongserialVersionUID = -7177035995799273674L;

   static JFramemyFrame;        //静态对象，要在main方法使用

   JPanelpanel;

   JButtonbuttonOpen,buttonSave,buttonQuit;

   StringsPath;

   //*****************************************************

   class MyButtonListennerimplements ActionListener{          //处理按钮事件

      publicvoid actionPerformed(ActionEvent event){

          if(event.getSource()==buttonOpen) openFileSub();

          if(event.getSource()==buttonSave) saveFileSub();

          if(event.getSource()==buttonQuit) System.exit(0);

      }

   }

   //*****************************************************

   //构造方法

   public JFileChooserDemo(){

      //创建框架窗口

      super("文件对话框");

      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      //创建并添加一个面板

      panel=new JPanel();

      getContentPane().add(panel);

      //创建按钮

      buttonOpen=new JButton("打开");panel.add(buttonOpen);

      buttonSave=new JButton("保存");panel.add(buttonSave);

      buttonQuit=new JButton("退出");panel.add(buttonQuit);

      //为按钮添加侦听

      MyButtonListenner buttonListen=new MyButtonListenner();

      buttonOpen.addActionListener(buttonListen);

      buttonSave.addActionListener(buttonListen);

      buttonQuit.addActionListener(buttonListen);

      //压缩整理窗口上的控件，置为可见

      pack();

      setVisible(true);

   }//end ofConstructor

   

   //main方法

   publicstaticvoid main(String[] args) {

      myFrame=new JFileChooserDemo();

   }

 

   publicvoid openFileSub(){

      JFileChooser chooser=new JFileChooser();

      FileNameExtensionFilter filter=new FileNameExtensionFilter("音频文件","mp3","wav","midi");

      chooser.setFileFilter(filter);

      int returnVal=chooser.showDialog(myFrame,"请选择要打开的文件");

      if(returnVal==JFileChooser.APPROVE_OPTION){

         sPath=chooser.getCurrentDirectory().toString()+"\\"+chooser.getSelectedFile().getName();

      }

      JOptionPane.showMessageDialog(myFrame,"你要打开的是："+sPath+"文件！");

   }//end of openFileSub

   

   publicvoid saveFileSub(){

      JFileChooser chooser=new JFileChooser();

      FileNameExtensionFilter filter=new FileNameExtensionFilter("JPG & GIF Images","jpg","gif");

      chooser.setFileFilter(filter);

      int returnVal=chooser.showDialog(myFrame,"请选择要保存的文件");

      if(returnVal==JFileChooser.APPROVE_OPTION){

         sPath=chooser.getCurrentDirectory().toString()+"\\"+chooser.getSelectedFile().getName();

      }

      JOptionPane.showMessageDialog(myFrame,"你要保存的是："+sPath+"文件！");

   }//end of savaFileSub

   

}