【实例简介】防止创建多个字符串对象

【实例截图】

【核心代码】

package com.mingrisoft;

import java.awt.EventQueue;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.io.FileWriter;

import java.io.IOException;

import javax.swing.JButton;

import javax.swing.JCheckBox;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.border.EmptyBorder;

public class HobbyFrame extends JFrame {

private static final long serialVersionUID = -3091839699328509198L;

private JPanel contentPane;

JCheckBox checkBox1;

JCheckBox checkBox4;

JCheckBox checkBox2;

JCheckBox checkBox5;

JCheckBox checkBox3;

JCheckBox checkBox6;

/**

* Launch the application.

*/

public static void main(String[] args) {

EventQueue.invokeLater(new Runnable() {

public void run() {

try {

HobbyFrame frame = new HobbyFrame();

frame.setVisible(true);

} catch (Exception e) {

e.printStackTrace();

}

}

});

}

/**

* Create the frame.

*/

public HobbyFrame() {

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setBounds(100, 100, 344, 224);

contentPane = new JPanel();

contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));

setContentPane(contentPane);

contentPane.setLayout(null);

setTitle("个人爱好");

JPanel panel = new JPanel();

panel.setBounds(0, 0, 335, 186);

contentPane.add(panel);

panel.setLayout(null);

JLabel label = new JLabel("你的个人爱好是：");

label.setBounds(41, 21, 105, 24);

panel.add(label);

checkBox1 = new JCheckBox("游泳");

checkBox1.setBounds(41, 51, 103, 23);

panel.add(checkBox1);

checkBox4 = new JCheckBox("旅游");

checkBox4.setBounds(187, 51, 103, 23);

panel.add(checkBox4);

checkBox2 = new JCheckBox("看书");

checkBox2.setBounds(41, 76, 103, 23);

panel.add(checkBox2);

checkBox5 = new JCheckBox("上网");

checkBox5.setBounds(187, 76, 103, 23);

panel.add(checkBox5);

checkBox3 = new JCheckBox("乒乓球");

checkBox3.setBounds(41, 101, 103, 23);

panel.add(checkBox3);

checkBox6 = new JCheckBox("羽毛球");

checkBox6.setBounds(187, 101, 103, 23);

panel.add(checkBox6);

JButton saveButton = new JButton("写入文件");

saveButton.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent arg0) {

do_button_actionPerformed(arg0);

}

});

saveButton.setBounds(176, 140, 93, 23);

panel.add(saveButton);

}

protected void do_button_actionPerformed(ActionEvent arg0) {

StringBuffer buffer = new StringBuffer();

if (checkBox1.isSelected()) { // 判断指定的复选框checkBox是否被选中

buffer.append(checkBox1.getText() " "); // 将可变的字符序列进行追加信息

}

if (checkBox4.isSelected()) {// 判断指定的复选框checkBox是否被选中

buffer.append(checkBox4.getText() " ");// 将可变的字符序列进行追加信息

}

if (checkBox2.isSelected()) {// 判断指定的复选框checkBox是否被选中

buffer.append(checkBox2.getText() " ");// 将可变的字符序列进行追加信息

}

if (checkBox5.isSelected()) {// 判断指定的复选框checkBox是否被选中

buffer.append(checkBox5.getText() " ");// 将可变的字符序列进行追加信息

}

if (checkBox3.isSelected()) {// 判断指定的复选框checkBox是否被选中

buffer.append(checkBox3.getText() " ");// 将可变的字符序列进行追加信息

}

if (checkBox6.isSelected()) {// 判断指定的复选框checkBox是否被选中

buffer.append(checkBox6.getText() " ");// 将可变的字符序列进行追加信息

}

FileWriter writer = null;

try {

writer = new FileWriter("d://hobby.txt");// 创建文件输出流对象

writer.write(buffer.toString());// 写入用户选择的爱好

writer.flush();// 清除缓存

} catch (IOException e) {

e.printStackTrace();

} finally {

if (writer != null) {

try {

writer.close();// 释放资源

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

}