java - 我想设置在 jtree 中调用的 jpanel 大小

Question

这是我用来调用 jpanel 的一段代码

JFrame frame = new JFrame();
JSplitPane sppane= new JSplitPane();
JTree tree = new JTree ();
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
frame.setsize(screenSize.getWidth(),screenSize.getHeight());
DefaultMutableTreeNode node1= new DefaultMutableTreeNode(childofthistree[0]);
eRMSNode[] childnode1= new eRMSNode[]{
            new eRMSNode("Jpanel1","jpanelimageonlefttree.gif"); }
DefaultMutableTreeNode parentnode=(DefaultMutableTreeNode) 
tree .getModel().getChild(root, 0);
for (Node Childtree : detailsoftree) {
    DefaultMutableTreeNode node = new DefaultMutableTreeNode(Childtree);
    parentnode.add(node);
}

现在显示 jpanel1。但问题是我无法在右侧显示的 jpanel1 右侧获得固定大小。