当您的文本超出查看区域的范围时，滚动条就会出现。不要使用绝对定位，因为手头这么闲聊，总是喜欢布局管理器，请务必阅读第一个链接的第一段，以了解使用布局管理器的优势。
您只需要做的就是使用这个东西：
Jtextarea msgArea = new Jtextarea(10, 10);msgArea.setWrapStyleWord(true);msgArea.setLineWrap(true);JScrollPane msgScroller = new JScrollPane(); msgScroller.setBorder( BorderFactory.createTitledBorder("Messages"));msgScroller.setViewportView(msgArea);panelObject.add(msgScroller);Here is a small program for your understanding :
import java.awt.*;import java.awt.event.*;import javax.swing.*;public class JtextareaScroller{ private Jtextarea msgArea; private JScrollPane msgScroller; private Jtextarea logArea; private JScrollPane logScroller; private JButton sendButton; private JButton terminateButton; private Timer timer; private int counter = 0; private String[] messages = { "Hello theren", "How you doing ?n", "This is a very long text that might won't fit in a single line :-)n", "Okay just to occupy more space, it's another line.n", "Don't read too much of the messages, instead work on the solution.n", "Byee byee :-)n", "Cheersn" }; private ActionListener timerAction = new ActionListener() { @Override public void actionPerformed(ActionEvent ae) { if (counter < messages.length) msgArea.append(messages[counter++]); else counter = 0; } }; private void displayGUI() { Jframe frame = new Jframe("Chat Messenger Dummy"); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); JPanel contentPane = new JPanel(); contentPane.setLayout(new BorderLayout(5, 5)); JPanel centerPanel = new JPanel(); centerPanel.setLayout(new GridLayout(0, 1, 5, 5)); logArea = new Jtextarea(10, 10); logArea.setWrapStyleWord(true); logArea.setLineWrap(true); logScroller = new JScrollPane(); logScroller.setBorder( BorderFactory.createTitledBorder("Chat Log")); logScroller.setViewportView(logArea); msgArea = new Jtextarea(10, 10); msgArea.setWrapStyleWord(true); msgArea.setLineWrap(true); msgScroller = new JScrollPane(); msgScroller.setBorder( BorderFactory.createTitledBorder("Messages")); msgScroller.setViewportView(msgArea); centerPanel.add(logScroller); centerPanel.add(msgScroller); JPanel bottomPanel = new JPanel(); terminateButton = new JButton("Terminate Session"); terminateButton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent ae) { if (timer.isRunning()) timer.stop(); else timer.start(); } }); sendButton = new JButton("Send"); bottomPanel.add(terminateButton); bottomPanel.add(sendButton); contentPane.add(centerPanel, BorderLayout.CENTER); contentPane.add(bottomPanel, BorderLayout.PAGE_END); frame.setContentPane(contentPane); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); timer = new Timer(1000, timerAction); timer.start(); } public static void main(String... args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { new JtextareaScroller().displayGUI(); } }); }}Here is the outcome of the same :
