当我打开文件第一次打开文件，但如果选择第二次相同的文件没有打开如何在java swing中做到这一点？

首先通过打开的menuitem打开文件，但是当第二次打开时，我选择在新选项卡中打开的文件。我的要求，它不是在新标签打开并显示消息文件已经存在。当我打开文件第一次打开文件，但如果选择第二次相同的文件没有打开如何在java swing中做到这一点？

这里是我的代码，

public class Open extends javax.swing.JFrame { 
JTextArea tx; 
int i=0; 
public Open() { 
initComponents(); 
} 


@SuppressWarnings("unchecked") 
// <editor-fold defaultstate="collapsed" desc="Generated Code">       
private void initComponents() { 

    tp = new javax.swing.JTabbedPane(); 
    jMenuBar1 = new javax.swing.JMenuBar(); 
    jMenu1 = new javax.swing.JMenu(); 
    Open = new javax.swing.JMenuItem(); 

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 

    jMenu1.setText("File"); 

    Open.setText("Open"); 
    Open.addActionListener(new java.awt.event.ActionListener() { 
     public void actionPerformed(java.awt.event.ActionEvent evt) { 
      OpenActionPerformed(evt); 
     } 
    }); 
    jMenu1.add(Open); 

    jMenuBar1.add(jMenu1); 

    setJMenuBar(jMenuBar1); 

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 
    getContentPane().setLayout(layout); 
    layout.setHorizontalGroup(
     layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
     .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE) 
    ); 
    layout.setVerticalGroup(
     layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
     .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 279, Short.MAX_VALUE) 
    ); 

    pack(); 
}// </editor-fold>       

private void OpenActionPerformed(java.awt.event.ActionEvent evt) {          
    final JFileChooser jc = new JFileChooser(); 
     JComponent panel = new JPanel((LayoutManager) new FlowLayout(
      FlowLayout.LEFT)); 

    int returnVal= jc.showOpenDialog(Open.this); 
    String title; 
    String sts; 
    File file=null; 
if(returnVal == JFileChooser.APPROVE_OPTION)  
file = jc.getSelectedFile();  
JTextArea text = new JTextArea(); 
if (jc.getSelectedFile()!= null) { 
    tx = new JTextArea(); 
    BufferedReader br = null; 
    StringBuffer str = new StringBuffer(""); 
    StringBuffer st = new StringBuffer(""); 
     try { 
     br = new BufferedReader(new FileReader(file)); 
     String line; 

       while ((line = br.readLine()) != null) { 
       str.append(line + "\n"); 
      } 
     } 
     catch (IOException ex) { 
       Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
     } 


    String t = str.toString(); 

    // tx = new JTextArea(); 

    final JInternalFrame internalFrame = new JInternalFrame("",true,true); 
    title=file.getName(); 
    sts=file.getPath(); 

    tx.setFont(new java.awt.Font("Miriam Fixed", 0, 13)); 
    //tx.setLineWrap(true); 
    internalFrame.add(tx); 
    i+=1; 
    internalFrame.setName("Doc "+i); 
    JScrollPane scrollpane=new JScrollPane(tx); 

      internalFrame.setTitle(title); 
    tp.add(internalFrame); 
    try{ 
     tp.setSelectedIndex(i-1); 
    } 
    catch(IndexOutOfBoundsException ioe){  
    } 
    internalFrame.add(scrollpane); 
    internalFrame.setVisible(true); 
    internalFrame.addInternalFrameListener(new InternalFrameAdapter() { 
     @Override 
     public void internalFrameClosing(InternalFrameEvent e) { 
      tp.remove(internalFrame); 
     } 
    }); 


    tx.setText(t); 
    try { 
      br.close(); 
      } 

     catch (IOException ex) { 
      Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
     } 
    }   
    }          
    public static void main(String args[]) { 

    java.awt.EventQueue.invokeLater(new Runnable() { 
     public void run() { 
       try { 
       UIManager.setLookAndFeel(
          UIManager.getSystemLookAndFeelClassName()); 
      } catch (ClassNotFoundException ex) { 
       Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
      } catch (InstantiationException ex) { 
       Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
      } catch (IllegalAccessException ex) { 
       Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
      } catch (UnsupportedLookAndFeelException ex) { 
       Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
      } 
      new Open().setVisible(true); 
     } 
    }); 
} 
// Variables declaration - do not modify      
private javax.swing.JMenuItem Open; 
private javax.swing.JMenu jMenu1; 
private javax.swing.JMenuBar jMenuBar1; 
private javax.swing.JTabbedPane tp; 
// End of variables declaration     
}

来源

2014-09-26 user3531731

您需要将'File'与'JInternalFrame'关联，使用某种'Map'。这样，你可以检查'Map'是否已经包含'File'，如果是，你可以提取关联的'JInternalFrame'并使其活跃......或者你想要做什么...... – MadProgrammer 2014-09-26 07:37:03

你可以试试看[Collections Trail]（http://docs.oracle.com/javase/tutorial/collections/） – MadProgrammer 2014-09-26 08:17:33

您可以维护AbsoluteFilepath的ArrayList中，当internalframe关闭从列表中删除。我已更新您的代码。请检查并回复

import javax.swing.*; 
import javax.swing.event.InternalFrameAdapter; 
import javax.swing.event.InternalFrameEvent; 
import java.awt.*; 
import java.io.BufferedReader; 
import java.io.File; 
import java.io.FileReader; 
import java.io.IOException; 
import java.util.ArrayList; 
import java.util.logging.Level; 
import java.util.logging.Logger; 


public class Open extends javax.swing.JFrame { 
JTextArea tx; 
ArrayList<String> fileList; 
int i=0; 
public Open() { 
    fileList=new ArrayList<String>(); 
    initComponents(); 
} 


@SuppressWarnings("unchecked") 
// <editor-fold defaultstate="collapsed" desc="Generated Code"> 
private void initComponents() { 

    tp = new javax.swing.JTabbedPane(); 
    jMenuBar1 = new javax.swing.JMenuBar(); 
    jMenu1 = new javax.swing.JMenu(); 
    Open = new javax.swing.JMenuItem(); 

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 

    jMenu1.setText("File"); 

    Open.setText("Open"); 
    Open.addActionListener(new java.awt.event.ActionListener() { 
     public void actionPerformed(java.awt.event.ActionEvent evt) { 
      OpenActionPerformed(evt); 
     } 
    }); 
    jMenu1.add(Open); 

    jMenuBar1.add(jMenu1); 

    setJMenuBar(jMenuBar1); 

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 
    getContentPane().setLayout(layout); 
    layout.setHorizontalGroup(
      layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
        .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE) 
    ); 
    layout.setVerticalGroup(
      layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
        .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 279, Short.MAX_VALUE) 
    ); 

    pack(); 
}// </editor-fold> 

private void OpenActionPerformed(java.awt.event.ActionEvent evt) { 
    final JFileChooser jc = new JFileChooser(); 
    JComponent panel = new JPanel((LayoutManager) new FlowLayout(
      FlowLayout.LEFT)); 

    int returnVal= jc.showOpenDialog(Open.this); 
    String title; 
    String sts; 
    File file=null; 
    if(returnVal == JFileChooser.APPROVE_OPTION) 
    file = jc.getSelectedFile(); 
    JTextArea text = new JTextArea(); 
    if (jc.getSelectedFile()!= null && !fileList.contains(file.getAbsolutePath())) { 
     fileList.add(file.getAbsolutePath()); 
     tx = new JTextArea(); 
     BufferedReader br = null; 
     StringBuffer str = new StringBuffer(""); 
     StringBuffer st = new StringBuffer(""); 
     try { 
      br = new BufferedReader(new FileReader(file)); 
      String line; 

      while ((line = br.readLine()) != null) { 
       str.append(line + "\n"); 
      } 
     } 
     catch (IOException ex) { 
      Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
     } 


     String t = str.toString(); 

     // tx = new JTextArea(); 

     final JInternalFrame internalFrame = new JInternalFrame("",true,true); 
     title=file.getName(); 
     sts=file.getPath(); 
     final String filePath=file.getAbsolutePath(); 
     tx.setFont(new java.awt.Font("Miriam Fixed", 0, 13)); 
     //tx.setLineWrap(true); 
     internalFrame.add(tx); 
     i+=1; 
     internalFrame.setName("Doc "+i); 
     JScrollPane scrollpane=new JScrollPane(tx); 

     internalFrame.setTitle(title); 
     tp.add(internalFrame); 
     try{ 
      tp.setSelectedIndex(i-1); 
     } 
     catch(IndexOutOfBoundsException ioe){ 
     } 
     internalFrame.add(scrollpane); 
     internalFrame.setVisible(true); 
     internalFrame.addInternalFrameListener(new InternalFrameAdapter() { 
      @Override 
      public void internalFrameClosing(InternalFrameEvent e) { 
       fileList.remove(filePath); 
       tp.remove(internalFrame); 
      } 
     }); 


     tx.setText(t); 
     try { 
      br.close(); 
     } 

     catch (IOException ex) { 
      Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
     } 
    } 
    else 
    { 
     JOptionPane.showMessageDialog(this, "File is already open"); 
    } 
} 
public static void main(String args[]) { 

    java.awt.EventQueue.invokeLater(new Runnable() { 
     public void run() { 
      try { 
       UIManager.setLookAndFeel(
         UIManager.getSystemLookAndFeelClassName()); 
      } catch (ClassNotFoundException ex) { 
       Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
      } catch (InstantiationException ex) { 
       Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
      } catch (IllegalAccessException ex) { 
       Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
      } catch (UnsupportedLookAndFeelException ex) { 
       Logger.getLogger(Open.class.getName()).log(Level.SEVERE, null, ex); 
      } 
      new Open().setVisible(true); 
     } 
    }); 
} 
// Variables declaration - do not modify 
private javax.swing.JMenuItem Open; 
private javax.swing.JMenu jMenu1; 
private javax.swing.JMenuBar jMenuBar1; 
private javax.swing.JTabbedPane tp; 
// End of variables declaration 
}

来源

2014-09-26 13:35:49 VaibJ

当我打开文件第一次打开文件，但如果选择第二次相同的文件没有打开如何在java swing中做到这一点？

回答

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