鼠标选定文本

import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class MyTest extends JFrame {
private JTextArea txtarea, txtarea2;

private Container C;

private JButton button;

public MyTest() {
super("JTextArea 'use ");

Box box1 = Box.createHorizontalBox();// 定义Box
txtarea = new JTextArea("", 20, 15);// JTextArea 定义
txtarea.setBackground(Color.pink);
C = getContentPane();// 暂定
box1.add(new JScrollPane(txtarea));

button = new JButton(&