JPanel 实际上只是一个容器，您可以在其中放入不同的元素（甚至是其他的JPanels）。因此，在您的情况下，我建议将一个大的JPanel 作为您窗口的某种主容器。 主面板您分配了一个适合您需要的Layout (here is an introduction to the layouts)。
将布局设置到您的主面板后，您可以添加绘画面板和您想要的其他JPanel（例如其中包含文本的那些..）。
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
JPanel paintPanel = new JPanel();
JPanel textPanel = new JPanel();
mainPanel.add(paintPanel);
mainPanel.add(textPanel);
这只是对所有子面板进行垂直（Y 轴）排序的示例。因此，如果您想要在 mainPanel 底部的其他一些东西（可能是一些图标或按钮）应该与另一个布局（如水平布局）一起组织，只需再次创建一个新的 JPanel 作为容器对于所有其他东西并设置setLayout(new BoxLayout(mainPanel, BoxLayout.X_AXIS)。
您会发现，布局非常严格，可能很难为您的面板找到最佳布局。所以不要放弃，阅读介绍（上面的链接）并查看图片 - 这就是我的做法:)
或者您可以只使用 NetBeans 来编写您的程序。你有一个非常简单的可视化编辑器（拖放）来创建各种窗口和框架。 （事后才理解代码……有时很棘手。）
编辑
由于有很多人对这个问题感兴趣，我想提供一个完整的示例，说明如何布局 JFrame 以使其看起来像 OP 想要的那样。
该类名为 MyFrame 并扩展了 swings JFrame
public class MyFrame extends javax.swing.JFrame{
// these are the components we need.
private final JSplitPane splitPane; // split the window in top and bottom
private final JPanel topPanel; // container panel for the top
private final JPanel bottomPanel; // container panel for the bottom
private final JScrollPane scrollPane; // makes the text scrollable
private final JTextArea textArea; // the text
private final JPanel inputPanel; // under the text a container for all the input elements
private final JTextField textField; // a textField for the text the user inputs
private final JButton button; // and a "send" button
public MyFrame(){
// first, lets create the containers:
// the splitPane devides the window in two components (here: top and bottom)
// users can then move the devider and decide how much of the top component
// and how much of the bottom component they want to see.
splitPane = new JSplitPane();
topPanel = new JPanel(); // our top component
bottomPanel = new JPanel(); // our bottom component
// in our bottom panel we want the text area and the input components
scrollPane = new JScrollPane(); // this scrollPane is used to make the text area scrollable
textArea = new JTextArea(); // this text area will be put inside the scrollPane
// the input components will be put in a separate panel
inputPanel = new JPanel();
textField = new JTextField(); // first the input field where the user can type his text
button = new JButton("send"); // and a button at the right, to send the text
// now lets define the default size of our window and its layout:
setPreferredSize(new Dimension(400, 400)); // let's open the window with a default size of 400x400 pixels
// the contentPane is the container that holds all our components
getContentPane().setLayout(new GridLayout()); // the default GridLayout is like a grid with 1 column and 1 row,
// we only add one element to the window itself
getContentPane().add(splitPane); // due to the GridLayout, our splitPane will now fill the whole window
// let's configure our splitPane:
splitPane.setOrientation(JSplitPane.VERTICAL_SPLIT); // we want it to split the window verticaly
splitPane.setDividerLocation(200); // the initial position of the divider is 200 (our window is 400 pixels high)
splitPane.setTopComponent(topPanel); // at the top we want our "topPanel"
splitPane.setBottomComponent(bottomPanel); // and at the bottom we want our "bottomPanel"
// our topPanel doesn't need anymore for this example. Whatever you want it to contain, you can add it here
bottomPanel.setLayout(new BoxLayout(bottomPanel, BoxLayout.Y_AXIS)); // BoxLayout.Y_AXIS will arrange the content vertically
bottomPanel.add(scrollPane); // first we add the scrollPane to the bottomPanel, so it is at the top
scrollPane.setViewportView(textArea); // the scrollPane should make the textArea scrollable, so we define the viewport
bottomPanel.add(inputPanel); // then we add the inputPanel to the bottomPanel, so it under the scrollPane / textArea
// let's set the maximum size of the inputPanel, so it doesn't get too big when the user resizes the window
inputPanel.setMaximumSize(new Dimension(Integer.MAX_VALUE, 75)); // we set the max height to 75 and the max width to (almost) unlimited
inputPanel.setLayout(new BoxLayout(inputPanel, BoxLayout.X_AXIS)); // X_Axis will arrange the content horizontally
inputPanel.add(textField); // left will be the textField
inputPanel.add(button); // and right the "send" button
pack(); // calling pack() at the end, will ensure that every layout and size we just defined gets applied before the stuff becomes visible
}
public static void main(String args[]){
EventQueue.invokeLater(new Runnable(){
@Override
public void run(){
new MyFrame().setVisible(true);
}
});
}
}
请注意，这只是一个示例，有多种布局窗口的方法。这完全取决于您的需求以及您是否希望内容可调整大小/响应。另一个非常好的方法是GridBagLayout，它可以处理相当复杂的布局，但学习起来也相当复杂。