Java-IO流

Java-IO流

从一个txt文件中，一行一行读取该文件的所有内容，并将内容一行一行打印在控制台。

import java.io.*;

public class Q1 {
     
    public Q1(String path) throws IOException {
     
        FileInputStream fi = new FileInputStream(path);
        InputStreamReader in = new InputStreamReader(fi,"UTF-8");
        BufferedReader br = new BufferedReader(in);
        String content = br.readLine();
        while(content != null){
     
            System.out.println(content);
            content = br.readLine();
        }
        br.close();
        in.close();
        fi.close();
    }

    public static void main(String[] args) {
     
        try {
     
            new Q1("D:/test.txt");
        } catch (IOException e) {
     
            e.printStackTrace();
        }
    }
}

创建一个如下所示的图形用户界面，用户可以在界面中输入文本，点击保存按钮后，可以将内容保存到c:\test.txt文件中。

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.FileWriter;
import java.io.IOException;

public class Q2 {
     
     JFrame Frame;
     JButton Button;
     TextArea Area;
    FileWriter fw;
    public Q2(String path){
     
        Frame = new JFrame("save txt");
        Button = new JButton("save test.txt");
        Frame.add(Button);
        Area = new TextArea(20,20);
        Frame.add(Area);
        Frame.setLayout(new FlowLayout());
        Frame.setSize(200,400);
        Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Frame.setLocationRelativeTo(null);
        Frame.setVisible(true);
        Button.addActionListener(new ActionListener() {
     
            @Override
            public void actionPerformed(ActionEvent e) {
     
                String content = Area.getText();
                try {
     
                    fw = new FileWriter(path);
                    fw.write(content);
                    fw.close();
                } catch (IOException ioException) {
     
                    ioException.printStackTrace();
                }
            }
        });
    }

    public static void main(String[] args) {
     
        new Q2("D:/Q2.txt");
    }
}