树控件的选择方式有三种，通过树控件的选择模型TreeSelectionModel对象进行设置，如下：

static int  CONTIGUOUS_TREE_SELECTION   
选择只能是连续的。
static int  DISCONTIGUOUS_TREE_SELECTION    
选择可以包含任何数量的不一定连续的项目。
static int  SINGLE_TREE_SELECTION   
选择一次只能包含一个路径。

对于选择路径TreePath对象，通过getLastPathComponent方法返回路径最后的节点。
通过一个实例，把左边选择的节点添加到右边的树控件中，代码如下：

public class SelectedTree extends JFrame
{
    public  JTree tree,tree1;
    public DefaultTreeModel dtm;
    public TreeSelectionModel dtst;
    static int index = 0;
    JTextField jtf ;
    StringBuffer str = new StringBuffer("数论");
    public SelectedTree()
    {
        JPanel panel = new JPanel();
        initTree();
        JPanel panel1 = new JPanel(new GridLayout(1,2));
        panel1.add(tree);
        panel1.add(tree1);
        add(panel1);
        tree.setBorder(new TitledBorder("普通树控件"));
        
        JButton jbn = new JButton("复制选择的节点信息");
        jbn.addActionListener(new ActionListener()
        {
            
            @Override
            public void actionPerformed(ActionEvent e)
            {
                // TODO Auto-generated method stub
                
                    addNodes(tree.getSelectionPaths());
                
                tree1.updateUI();
                
            }   
        });
        
        panel.add(jbn);
        add(panel, BorderLayout.SOUTH);
        init();
    }
    //递归添加节点
    private void addNodes(DefaultMutableTreeNode node, DefaultMutableTreeNode addNode)
    {
        
        DefaultMutableTreeNode t1 = new DefaultMutableTreeNode(addNode.getUserObject());
        node.add(t1);
        if(!addNode.isLeaf())
        {
            for(int j=0;j<addNode.getChildCount();j++)
                addNodes(t1,(DefaultMutableTreeNode)addNode.getChildAt(j));
        }
    }
    private void addNodes(TreePath[] tps)
    {
        DefaultTreeModel dtm1 = (DefaultTreeModel) tree1.getModel();
        DefaultMutableTreeNode root = (DefaultMutableTreeNode) dtm1.getRoot();
        for(int i=0;i<tps.length;i++)
        {
            DefaultMutableTreeNode temp = (DefaultMutableTreeNode) tps[i].getLastPathComponent();
            DefaultMutableTreeNode t1 = new DefaultMutableTreeNode(temp.getUserObject());
            root.add(t1);
            if(!temp.isLeaf())
            {
                for(int j=0;j<temp.getChildCount();j++)
                    addNodes(t1,(DefaultMutableTreeNode)temp.getChildAt(j));
            }
        }
        
    }
    
    private void initTree()
    {
        // TODO Auto-generated method stub
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("科学");
        DefaultMutableTreeNode shuxue = new DefaultMutableTreeNode("数学");
        DefaultMutableTreeNode jisuanji = new DefaultMutableTreeNode("计算机");
        root.add(shuxue);
        root.add(jisuanji);
        addTreeNode(shuxue,new String[] {str.toString(),"几何","代数"});
        addTreeNode(jisuanji,new String[] {"编程语言","操作系统","算法"});
        tree = new JTree(root);
        tree.setEditable(true);
        //tree.setDragEnabled(true);
        dtst = tree.getSelectionModel();
        dtm = (DefaultTreeModel) tree.getModel();
        DefaultMutableTreeNode root1 = new DefaultMutableTreeNode("科学");
        tree1 = new JTree(root1);
    }
    
    
    private void addTreeNode(DefaultMutableTreeNode parent, String[] strs)
    {
        for(int i = 0;i<strs.length;i++)
        {
            DefaultMutableTreeNode temp = new DefaultMutableTreeNode(strs[i]);
            parent.add(temp);
        }
        
    }

    //对树控件进行初始化，例如图标
    
    public void init()
    {

        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setSize(600, 500);
        this.setLocationRelativeTo(null);
        this.setTitle("树控件");
        this.setVisible(true);
    }
}

通过节点添加，需要更新树控件。
运行如下：

1.png

2.png

由于水平有限，如果有错误，请大家多多指导，提高水平，共同学习。