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jContentPane添加的两个方法没有写
发表在Java图书答疑
2020-02-08 悬赏:66 学分
《Java从入门到精通(第4版)》第15章 I/O(输入/输出) 279页-281页
是否精华
是
否
版块置顶:
是
否
package assignments; import java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.File; import java.io.FileReader; import java.io.FileWriter; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTextArea; public class Ftest extends JFrame { private static final long serialVersionUID = 1L; // 创建面板对象 // 创建文本域对象 // 创建控制面板对象 // 创建按钮对象 private JPanel jContentPane = null; private JTextArea jTextArea = null; private JPanel controlPane = null; private JButton closeButton = null; private JButton openButton = null; private JButton getOpenButton() { if (openButton == null) { openButton = new JButton(); openButton.setText("写入文件"); openButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { File file = new File("word.txt"); try { // 创建FileWriter对象 FileWriter out = new FileWriter(file); // 获取文本域中文本 String s = jTextArea.getText(); // 将信息写入磁盘文件 out.write(s); // 将流关闭 out.close(); } catch (Exception e1) { e1.printStackTrace(); } } }); } return openButton; } private JButton getCloseButton() { if (closeButton == null) { closeButton = new JButton(); closeButton.setText("读取文件"); closeButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { File file = new File("word.txt"); try { FileReader in = new FileReader(file); char ch[] = new char[1024]; int len = in.read(ch); // 设置文本域的显示信息 jTextArea.setText(new String(ch, 0, len)); in.close(); } catch (Exception e1) { e1.printStackTrace(); } } }); } return closeButton; } public Ftest() { super(); initialize(); } private void initialize() { this.setSize(300, 200); this.setContentPane(getJContentPane()); this.setTitle("JFrame"); } private JPanel getJContentPane() { if (jContentPane == null) { jContentPane = new JPanel(); jContentPane.setLayout(new BorderLayout()); jContentPane.add(getJTextArea(), BorderLayout.CENTER); jContentPane.add(getControlPanel(), BorderLayout.SOUTH); } return jContentPane; } public static void main(String[] args) { Ftest thisClass = new Ftest(); thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); thisClass.setVisible(true); } }