保留完整的原有功能的基础上，确保滚动条显示为最新的界面private void initMsgPanel(){ msgPanel=new JPanel(); msgPanel.setLayout(new BoxLayout(msgPanel, BoxLayout.Y_AXIS)); msgPanel.setBackground(Color.WHITE); JScrollPane scrollPane = new JScrollPane(msgPanel); scrollPane.setBounds(5,5,370,330); add(scrollPane); } private void msgAddToMsgPanel(String msg,int align){ System.out.println("==========msgAddToMsgPanel==========="+msg); JLabel msgLbl=new JLabel(msg,SwingConstants.CENTER); msgLbl.setForeground(Color.decode("#61565A")); msgLbl.setBackground(Color.decode("#BACCD9")); msgLbl.setSize(50,25); msgLbl.setBorder(BorderFactory.createLineBorder(Color.getColor("#8FB2C9"),2,true)); msgLbl.setOpaque(true);//设置不透明 JPanel itemPanel=new JPanel(); itemPanel.setBackground(Color.WHITE); itemPanel.setPreferredSize(new Dimension(msgPanel.getWidth(),25)); itemPanel.add(msgLbl); FlowLayout layout = (FlowLayout) itemPanel.getLayout(); layout.setAlignment(align); msgPanel.add(itemPanel); msgPanel.updateUI(); }

为了确保滚动条显示为最新的界面，可以在添加消息后，将滚动条设置到最底部。修改后的代码如下：

private void initMsgPanel(){
    msgPanel=new JPanel();
    msgPanel.setLayout(new BoxLayout(msgPanel, BoxLayout.Y_AXIS));
    msgPanel.setBackground(Color.WHITE);

    JScrollPane scrollPane = new JScrollPane(msgPanel);
    scrollPane.setBounds(5,5,370,330);
    add(scrollPane);
}

private void msgAddToMsgPanel(String msg,int align){
    System.out.println("==========msgAddToMsgPanel==========="+msg);
    JLabel msgLbl=new JLabel(msg,SwingConstants.CENTER);
    msgLbl.setForeground(Color.decode("#61565A"));
    msgLbl.setBackground(Color.decode("#BACCD9"));
    msgLbl.setSize(50,25);
    msgLbl.setBorder(BorderFactory.createLineBorder(Color.getColor("#8FB2C9"),2,true));
    msgLbl.setOpaque(true);//设置不透明

    JPanel itemPanel=new JPanel();
    itemPanel.setBackground(Color.WHITE);
    itemPanel.setPreferredSize(new Dimension(msgPanel.getWidth(),25));
    itemPanel.add(msgLbl);

    FlowLayout layout = (FlowLayout) itemPanel.getLayout();
    layout.setAlignment(align);

    msgPanel.add(itemPanel);
    msgPanel.updateUI();

    // 将滚动条设置到最底部
    JScrollBar vertical = ((JScrollPane)msgPanel.getParent()).getVerticalScrollBar();
    vertical.setValue(vertical.getMaximum());
}

在msgAddToMsgPanel()方法的最后，添加了获取滚动条并将其设置到最底部的代码。这样就能保证每次添加消息后，滚动条都会自动滑动到最底部。