1 public class JTreeKnow extends JFrame
2 {
3 public JTreeKnow()
4 {
5 this.setBounds(300, 100, 400, 500);
6 this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
7
8 //创建树的第一种方式
9 JTree jTree = new JTree();
10 this.add(jTree);
11
12 //创建树的第二种方式：推荐
13 //创建根节点
14 DefaultMutableTreeNode defaultMutableTreeNode = new DefaultMutableTreeNode("根节点");
15 //创建树模型
16 DefaultTreeModel defaultTreeModel = new DefaultTreeModel(defaultMutableTreeNode);
17 //创建树
18 JTree jTree2 = new JTree(defaultTreeModel);
19 //创建滚动面板
20 JScrollPane jScrollPane = new JScrollPane(jTree2);
21 this.add(jScrollPane);
22 //添加子节点
23 for(int i = 1; i < 3; i++)
24 {
25 DefaultMutableTreeNode defaultMutableTreeNode2 = new DefaultMutableTreeNode("第一阶子节点"+i);
26 for(int j = 1; j < 4; j++)
27 {
28 DefaultMutableTreeNode defaultMutableTreeNode3 = new DefaultMutableTreeNode("第二阶子节点"+i+j);
29 defaultMutableTreeNode2.add(defaultMutableTreeNode3);
30 }
31 defaultMutableTreeNode.add(defaultMutableTreeNode2);
32 }
33
34 //获取根节点
35 DefaultMutableTreeNode defaultMutableTreeNode2 = (DefaultMutableTreeNode) defaultTreeModel.getRoot();
36 //根据父节点索引+子节点索引找到节点
37 DefaultMutableTreeNode defaultMutableTreeNode3 = (DefaultMutableTreeNode) defaultTreeModel.getChild(defaultMutableTreeNode2, 0);
38 System.out.println(defaultMutableTreeNode3);
39 //获取某一节点到顶级节点（根节点）之间所有的节点
40
41 //获取某节点所对应的阶层
42 int level = defaultMutableTreeNode3.getLevel();
43
44 //刷新重新绘制节点数（重要）
45 defaultTreeModel.reload();
46 //获取所有节点：迭代器
47 Enumeration<DefaultMutableTreeNode> nodes = defaultMutableTreeNode.children();
48 //判断某节点是否是根节点、页节点isLeaf()
49 ((DefaultMutableTreeNode)defaultMutableTreeNode.getChildAt(0)).isRoot();
50
51 /*******************************************监听器****************************************/
52 //
53 /***************JTree的监听器**************/
54 //绑定选项监听器
55 //某节点被选中了
56 jTree2.addTreeSelectionListener(new TreeSelectionListener()
57 {
58 @Override
59 public void valueChanged(TreeSelectionEvent e)
60 {
61 // TODO Auto-generated method stub
62 // System.out.println("节点被选择");
63 //获取选中的treePath,treePath即根节点至所选节点的集合
64 // System.out.println(tree.getSelectionPath());
65 // //获取节点集合的数量
66 // System.out.println(tree.getSelectionPath().getPathCount());
67 // //获取选中的节点对象
68 // System.out.println((DefaultMutableTreeNode)tree.getSelectionPath().getLastPathComponent());
69
70 System.out.println(e.getPath().getLastPathComponent());
71 }
72 });
73 //为降低程序的错误率，监听器addTreeWillExpandListener和监听器addTreeExpansionListener通常会同时搭配使用，
74 //以确保程序菜单正常、正确打开
75 //绑定数结展开折叠的监听器
76 //节点被展开了
77 jTree2.addTreeExpansionListener(new TreeExpansionListener()
78 {
79 /**
80 * 展开事件
81 */
82 @Override
83 public void treeExpanded(TreeExpansionEvent event)
84 {
85 // TODO Auto-generated method stub
86 System.out.println(event.getPath().getLastPathComponent()+" 被展开");
87 }
88 /**
89 * 折叠
90 */
91 @Override
92 public void treeCollapsed(TreeExpansionEvent event)
93 {
94 // TODO Auto-generated method stub
95 System.out.println(event.getPath().getLastPathComponent()+" 被折叠");
96 }
97 });
98
99 //绑定树结构将要执行展开和折叠的监听器
100 //节点将被展开：通常使用本方法对节点进行动态的显示控制
101 jTree2.addTreeWillExpandListener(new TreeWillExpandListener()
102 {
103 /**
104 * 将被展开的事件
105 */
106 @Override
107 public void treeWillExpand(TreeExpansionEvent event)
108 throws ExpandVetoException
109 {
110 // TODO Auto-generated method stub
111 System.out.println(event.getPath().getLastPathComponent()+" 将被展开");
112
113 }
114 /**
115 * 将被折叠的事件
116 */
117 @Override
118 public void treeWillCollapse(TreeExpansionEvent event)
119 throws ExpandVetoException
120 {
121 // TODO Auto-generated method stub
122 System.out.println(event.getPath().getLastPathComponent()+" 将被折叠");
123 }
124 });
125 }
126 public static void main(String[] args)
127 {
128 JTreeKnow jTreeKnow = new JTreeKnow();
129 jTreeKnow.setVisible(true);
130 }
131 }
