在JTextArea中打開，編輯和保存文本到.txt文件

Question

我正在搞java swing，並試圖用JTextArea打開一個包含現有數據的文本文件。無論我嘗試過不同的事情，它似乎都不會保存任何更改。

下面是讀取文本文件的代碼，但不寫（顯然）。

如果有人可以請我告訴我如何成功地保存對JTextArea的更改，我會非常感激。

package funwithswing; 


import java.awt.*; 
import javax.swing.*; 
import java.io.*; 
import java.util.Scanner; 
import javax.swing.border.EmptyBorder; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 

public class AllDataGUI extends JFrame{ 

    public AllDataGUI(){ 
     fileRead(); 
     panels();   
    } 

    private String storeAllString=""; 
    private JButton saveCloseBtn = new JButton("Save Changes and Close"); 
    private JButton closeButton = new JButton("Exit Without Saving"); 
    private JFrame frame=new JFrame("Viewing All Program Details"); 
    private JTextArea textArea = new JTextArea(storeAllString,0,70); 


    private JButton getCloseButton(){ 
     return closeButton; 
    }  

    private void fileRead(){ 
     try{  
      FileReader read = new FileReader("CompleteData.txt"); 
      Scanner scan = new Scanner(read); 
      while(scan.hasNextLine()){ 
       String temp=scan.nextLine()+"\n"; 
       storeAllString=storeAllString+temp; 
      } 
     } 
     catch (Exception exception) 
     { 
     exception.printStackTrace(); 
     } 
    }  

    private void fileWrite(){ 
     try{ 
      FileWriter write = new FileWriter ("CompleteData.txt"); 
      textArea.write(write); 
     } 
     catch (Exception e){ 
      e.printStackTrace(); 
     }   
    } 

    private void panels(){   
     JPanel panel = new JPanel(new GridLayout(1,1)); 
     panel.setBorder(new EmptyBorder(5, 5, 5, 5)); 
     JPanel rightPanel = new JPanel(new GridLayout(15,0,10,10)); 
     rightPanel.setBorder(new EmptyBorder(15, 5, 5, 10)); 
     JTextArea textArea = new JTextArea(storeAllString,0,70); 
      JScrollPane scrollBarForTextArea=new JScrollPane(textArea,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED); 
      panel.add(scrollBarForTextArea); 
      frame.add(panel); 
     frame.getContentPane().add(rightPanel,BorderLayout.EAST); 
     rightPanel.add(saveCloseBtn); 
      rightPanel.add(closeButton); 
      closeButton.addActionListener(new ActionListener() { 
        public void actionPerformed(ActionEvent e) 
        { 
         frame.dispose(); 

        } 
     }); 
      frame.setSize(1000, 700); 
      frame.setVisible(true); 
      frame.setLocationRelativeTo(null); 

} 

    private void saveBtn(){ 

    } 
} 

Answer 1

你的代碼有一些錯誤，我修改了這些。編譯並運行下面的代碼這將解決您的問題。

import java.awt.*; 
import javax.swing.*; 
import java.io.*; 
import java.util.Scanner; 
import javax.swing.border.EmptyBorder; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 

public class AllDataGUI extends JFrame{ 

    public AllDataGUI(){ 
     fileRead(); 
     panels();   
    } 

    private String storeAllString=""; 
    private JButton saveCloseBtn = new JButton("Save Changes and Close"); 
    private JButton closeButton = new JButton("Exit Without Saving"); 
    private JFrame frame=new JFrame("Viewing All Program Details"); 
    // private JTextArea textArea = new JTextArea(storeAllString,0,70); 
    private JTextArea textArea = new JTextArea(); 


    private JButton getCloseButton(){ 
     return closeButton; 
    }  

    private void fileRead(){ 
     try{  
      FileReader read = new FileReader("CompleteData.txt"); 
      Scanner scan = new Scanner(read); 
      while(scan.hasNextLine()){ 
       String temp=scan.nextLine()+"\n"; 
       storeAllString=storeAllString+temp; 
      } 
      textArea.setText(storeAllString); 
     } 
     catch (Exception exception) 
     { 
     exception.printStackTrace(); 
     } 
    }  



    private void panels(){   
     JPanel panel = new JPanel(new GridLayout(1,1)); 
     panel.setBorder(new EmptyBorder(5, 5, 5, 5)); 
     JPanel rightPanel = new JPanel(new GridLayout(15,0,10,10)); 
     rightPanel.setBorder(new EmptyBorder(15, 5, 5, 10)); 
     // JTextArea textArea = new JTextArea(storeAllString,0,70); 
      JScrollPane scrollBarForTextArea=new JScrollPane(textArea,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED); 
      panel.add(scrollBarForTextArea); 
      frame.add(panel); 
     frame.getContentPane().add(rightPanel,BorderLayout.EAST); 
     rightPanel.add(saveCloseBtn); 
      rightPanel.add(closeButton); 
      closeButton.addActionListener(new ActionListener() { 
        public void actionPerformed(ActionEvent e) 
        { 
         frame.dispose(); 

        } 
     }); 
      saveCloseBtn.addActionListener(new ActionListener() { 

      public void actionPerformed(ActionEvent e) { 
       saveBtn(); 
       frame.dispose(); 

      } 
     }); 
      frame.setSize(1000, 700); 
      frame.setVisible(true); 
      frame.setLocationRelativeTo(null); 

} 

    private void saveBtn(){ 
     File file = null; 
     FileWriter out=null; 


     try { 
      file = new File("CompleteData.txt"); 
      out = new FileWriter(file);  
      out.write(textArea.getText()); 
      out.close(); 
     } catch (FileNotFoundException e) { 
      e.printStackTrace(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 
    public static void main(String[] arg) 
    { 
     new AllDataGUI(); 
    } 
} 

Answer 2

您需要關閉FileWriter。使用Java-7或finally塊的try-with-resource可正確關閉資源。

private void fileWrite(){ 
    FileWriter write=null; 
    try{ 
     write = new FileWriter ("CompleteData.txt"); 
     textArea.write(write);   
    } 
    catch (Exception e){ 
     e.printStackTrace(); 
    } 
    finally{ 
     if(write != null) 
     write.close(); 
    } 
}