Java 组件及事件处理实训 实训1： 编写一个窗体程序，能够对文本区中的文字设置字体和大小。

实训要求： 

使用两个下拉框分别存放字体和字号的选项。其中字体从当前操作系统中获取。

选择字体和字号后，文本区中的文字会相应改变。

代码：

import java.awt.*;import java.awt.event.*;import javax.swing.*;public class FontChange extends JFrame implements ItemListener {JComboBox fontName;JComboBox fontSize;JTextArea txtContent;Font font;final String[] fontArr;final String strArr = "去年今日此门中，\n" + "人面桃花相映红。\n" + "人面不知何处去，\n"+ "桃花依旧笑春风。";final String[] sizeArr = { "8", "9", "10", "12", "14", "16", "18", "20","24", "28", "32", "36", "40", "44", "48", "54", "60", "66", "72","80", "88", "96" };public FontChange() {super("改变字体");txtContent = new JTextArea();txtContent.setText(strArr);JScrollPane jsp = new JScrollPane(txtContent);GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();fontArr = env.getAvailableFontFamilyNames();fontName = new JComboBox(fontArr);fontSize = new JComboBox(sizeArr);fontSize.setPreferredSize(new Dimension(80, 27));fontName.addItemListener(this);fontSize.addItemListener(this);fontName.setSelectedItem("宋体");fontSize.setSelectedItem("16");FlowLayout layout = new FlowLayout(FlowLayout.CENTER, 40, 5);JPanel pan = new JPanel(layout);pan.add(fontName);pan.add(fontSize);Container c = this.getContentPane();c.add(pan, BorderLayout.NORTH);c.add(jsp, BorderLayout.CENTER);this.setSize(400, 300);this.setResizable(false);this.setVisible(true);this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);}public void itemStateChanged(ItemEvent e) {String s = (String) fontName.getSelectedItem();int n = Integer.parseInt((String) fontSize.getSelectedItem());font = new Font(s, Font.PLAIN, n);txtContent.setFont(font);}public static void main(String[] args) {new FontChange();}}

运行结果：