【Java实验】使用GUI实现文本文件读写显示

import java.awt.Container;

import java.awt.FlowLayout;

import java.awt.TextArea;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

import javax.swing.JButton;

import javax.swing.JFrame;

public class GUIDemo extends JFrame{

private static final String TARGET_FILE = "./temp.txt";

//三个组件

private JButton saveButton;

private JButton loadButton;

private TextArea textArea;

//容器

private Container container;

//目标文件

private File targetFile;

public GUIDemo() throws IOException {

//设置title

super("File Demo");

//设置流布局

setLayout(new FlowLayout());

//获取容器

container = getContentPane();

//创建目标文件对象

targetFile = new File(TARGET_FILE);

if(targetFile.createNewFile()) {

System.out.println("文件不存在，货币代码创建成功");

}else {

System.out.println("文件存在");

}

//三个组件

textArea = new TextArea();

saveButton = new JButton("save");

loadButton = new JButton("load");

//保存文件按钮点击事件

saveButton.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

try {

//打开文件字符输出流

FileWriter writer = new FileWriter(targetFile);

//获取文本显示区文本

String result = textArea.getText();

//写入文件

writer.write(result);

//关闭输出流

writer.close();

//清空文本显示区内容

textArea.setText("");

System.out.println("存档成功");

} catch (IOException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

}

});

//读入文件按钮点击事件

loadButton.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

try {

//字符读入流

FileReader reader = new FileReader(targetFile);

//读入缓冲区

char[] buffer = new char[1024];

//读入结果

StringBuffer result = new StringBuffer();

//每次读入缓冲区的长度

int len;

//从读入流中读取文件内容并形成结果

while((len = reader.read(buffer)) != -1) {

result.append(buffer,0,len);

}

//关闭读入流

reader.close();

//更新文本显示区内容

textArea.setText(result.toString());

System.out.println("读档成功");

} catch (FileNotFoundException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

} catch (IOException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

}

});

//装填三个组件

container.add(textArea);

container.add(loadButton);

container.add(saveButton);

//调整大小

setSize(500, 300);

//显示

setVisible(true);

}

public static void main(String[] args) throws IOException {

GUIDemo demo = new GUIDemo();

demo.setDefaultCloseOperation(EXIT_ON_CLOSE);

}

}