有谁可以提供一个简单的class给我.要求是打开一个指定路径文本文件.把它的内容读出来.用System.out.println显示

Question

//try this code below
//this code using JTextArea to show your .txt file
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;public class Test4 extends JFrame
   implements ActionListener{      JLabel label1;
      JButton enterButton;
      JTextField enterField;
      JTextArea outputArea;      public Test4()
      {
         super ("Inner class Demonstration");         Container container = getContentPane();
         container.setLayout(new FlowLayout());         label1 = new JLabel ("Enter file name" );
         container.add(label1);         enterField = new JTextField (10);
         container.add(enterField);
         enterField.addActionListener(this) ;         enterButton  = new JButton("Read");
         container.add(enterButton);
         enterButton.addActionListener(this) ;         outputArea = new JTextArea (8,20);
         container.add(outputArea);
      }      public static void main(String args[])
      {
         Test4 window =  new Test4();
         window.setSize(300,250);
         window.setVisible(true);
      }      public void actionPerformed (ActionEvent actionEvent)
      {
         String fileName = enterField.getText();
         String output = "";
         StringBuffer buffer = new StringBuffer();
         try
         {
           // initialise the file to be read.
           FileInputStream in = new FileInputStream(fileName);
           // now create the object of Buffered Reader.
           InputStreamReader stream = new InputStreamReader(in);
           BufferedReader reader = new BufferedReader(stream);           while ((output = reader.readLine())!= null)
           buffer.append(output + "\n");           outputArea.setText(buffer.toString());           in.close();
          }          catch (IOException ioException)
          {
             JOptionPane.showMessageDialog(null,"File error","File error",JOptionPane.ERROR_MESSAGE ) ;
          }          catch (Exception exception)
          {
             JOptionPane.showMessageDialog(null,"error","error",JOptionPane.ERROR_MESSAGE);
          }
        }
   }

Answer 1

//try this code 
//this code using System.out to show your .txt file in your cosole 
//windowimport java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;public class Test5 extends JFrame
   implements ActionListener{      JLabel label1;
      JTextField enterField;      public Test5()
      {
         super ("Inner class Demonstration");         Container container = getContentPane();
         container.setLayout(new FlowLayout());         label1 = new JLabel ("Enter file name" );
         container.add(label1);
         enterField = new JTextField (10);
         container.add(enterField);
         enterField.addActionListener(this) ;
      }      public static void main(String args[])
      {
         Test5 window =  new Test5();
         window.setSize(300,70);
         window.setVisible(true);
      }      public void actionPerformed (ActionEvent actionEvent)
      {
         String fileName = enterField.getText();
         String output = "";
         StringBuffer buffer = new StringBuffer();
         try
         {
           // initialise the file to be read.
           FileInputStream in = new FileInputStream(fileName);
           // now create the object of Buffered Reader.
           InputStreamReader stream = new InputStreamReader(in);
           BufferedReader reader = new BufferedReader(stream);           while ((output = reader.readLine())!= null)
           buffer.append(output + "\n");           System.out.println(buffer.toString());           in.close();
          }          catch (IOException ioException)
          {
             JOptionPane.showMessageDialog(null,"File error","File error",JOptionPane.ERROR_MESSAGE ) ;
          }          catch (Exception exception)
          {
             JOptionPane.showMessageDialog(null,"error","error",JOptionPane.ERROR_MESSAGE);
          }
        }
   }