java swing 树型结构

package swing_advance;
import javax.swing.*;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.*;

import java.awt.*;
import java.beans.PropertyChangeListener;

public class TreeSelection extends JFrame {

public TreeSelection(){
Container c=getContentPane();
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
setSize(200,300);

DefaultMutableTreeNode root = new DefaultMutableTreeNode("根节点");
DefaultMutableTreeNode child1 = new DefaultMutableTreeNode("子节点A");
DefaultMutableTreeNode child2 = new DefaultMutableTreeNode("子节点B");

DefaultMutableTreeNode childchild1 = new DefaultMutableTreeNode("子节点AA",false);
DefaultMutableTreeNode childchild2 = new DefaultMutableTreeNode("子节点BB",false);

root.add(child1);
root.add(child2);
child1.add(childchild1);
child2.add(childchild2);
DefaultTreeModel dt=new DefaultTreeModel(root,true);
final JTree jt = new JTree(dt);

c.add(jt,BorderLayout.WEST);
setVisible(true);

TreeSelectionModel treeselect = jt.getSelectionModel();
treeselect.setSelectionMode(TreeSelectionModel.CONTIGUOUS_TREE_SELECTION);

jt.addTreeSelectionListener(new TreeSelectionListener() {

@Override
public void valueChanged(TreeSelectionEvent e) {
// TODO Auto-generated method stub
if(!jt.isSelectionEmpty()){
TreePath[] selectionpath=jt.getSelectionPaths();  //获得所有被选中的节点
for(int i=0;i<selectionpath.length;i++){
TreePath treepath=selectionpath[i];
//object 数组的形式返回数组
Object[] path=treepath.getPath();
for(int j=0;j<path.length;j++){
DefaultMutableTreeNode node=(DefaultMutableTreeNode)path[i];
String s=node.getUserObject()+(j==(path.length-1)?"":"-->");
System.out.println(s);

}
System.out.println();

}
}
}
});
}
public static void main(String[] args) {
// TODO Auto-generated method stub
new TreeSelection();
}

}