疯狂JAVA讲义---第十二章：Swing编程（七）JTree树

树这东西给用户的感觉极为方便，但给程序员带来很大的麻烦，它是swing中最麻烦的控件之一。树要弄的好非常麻烦，图标的美化，层次的划分，各种事件的处理。。。对于初学者来说，就不要太讲究样式，下面举个粗糙的例子，eg

[c-sharp] view plain copy print ?

1. public class SimpleJTree   
2. { 
3.     JFrame jf = new JFrame("简单树"); 
4.  
5.     JTree tree; 
6.     //定义几个初始节点 
7.     DefaultMutableTreeNode root = new DefaultMutableTreeNode("中国");  
8.     DefaultMutableTreeNode guangdong = new DefaultMutableTreeNode("广东"); 
9.     DefaultMutableTreeNode guangxi = new DefaultMutableTreeNode("广西"); 
10.     DefaultMutableTreeNode foshan = new DefaultMutableTreeNode("佛山"); 
11.     DefaultMutableTreeNode shantou = new DefaultMutableTreeNode("汕头"); 
12.     DefaultMutableTreeNode guilin = new DefaultMutableTreeNode("桂林"); 
13.     DefaultMutableTreeNode nanning = new DefaultMutableTreeNode("南宁"); 
14.  
15.     public void init() 
16.     { 
17.         //通过add方法建立树节点之间的父子关系 
18.         guangdong.add(foshan); 
19.         guangdong.add(shantou); 
20.         guangxi.add(guilin); 
21.         guangxi.add(nanning); 
22.         root.add(guangdong); 
23.         root.add(guangxi); 
24.         //以根节点创建树 
25.         tree = new JTree(root); 
26.  
27.         //默认连线 
28.         //tree.putClientProperty("JTree.lineStyle" , "Angeled"); 
29.         //没有连线 
30.         tree.putClientProperty("JTree.lineStyle" , "None"); 
31.         //水平分隔线 
32.         //tree.putClientProperty("JTree.lineStyle" , "Horizontal");  
33.  
34.  
35.         //设置是否显示根节点的“展开/折叠”图标,默认是false 
36.         tree.setShowsRootHandles(true); 
37.         //设置节点是否可见,默认是true 
38.         tree.setRootVisible(true); 
39.  
40.         jf.add(new JScrollPane(tree)); 
41.         jf.pack(); 
42.         jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
43.         jf.setVisible(true); 
44.     } 
45.  
46.     public static void main(String[] args)  
47.     { 
48.         new SimpleJTree().init(); 
49.     } 
50. } 

public class SimpleJTree { JFrame jf = new JFrame("简单树"); JTree tree; //定义几个初始节点 DefaultMutableTreeNode root = new DefaultMutableTreeNode("中国"); DefaultMutableTreeNode guangdong = new DefaultMutableTreeNode("广东"); DefaultMutableTreeNode guangxi = new DefaultMutableTreeNode("广西"); DefaultMutableTreeNode foshan = new DefaultMutableTreeNode("佛山"); DefaultMutableTreeNode shantou = new DefaultMutableTreeNode("汕头"); DefaultMutableTreeNode guilin = new DefaultMutableTreeNode("桂林"); DefaultMutableTreeNode nanning = new DefaultMutableTreeNode("南宁"); public void init() { //通过add方法建立树节点之间的父子关系 guangdong.add(foshan); guangdong.add(shantou); guangxi.add(guilin); guangxi.add(nanning); root.add(guangdong); root.add(guangxi); //以根节点创建树 tree = new JTree(root); //默认连线 //tree.putClientProperty("JTree.lineStyle" , "Angeled"); //没有连线 tree.putClientProperty("JTree.lineStyle" , "None"); //水平分隔线 //tree.putClientProperty("JTree.lineStyle" , "Horizontal"); //设置是否显示根节点的“展开/折叠”图标,默认是false tree.setShowsRootHandles(true); //设置节点是否可见,默认是true tree.setRootVisible(true); jf.add(new JScrollPane(tree)); jf.pack(); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jf.setVisible(true); } public static void main(String[] args) { new SimpleJTree().init(); } }

拖动，编辑树节点也是树的基本功能，下面就在上面例子的基础上，加上这些功能，eg

[java] view plain copy print ?

1. public class EditJTree 
2. { 
3.     JFrame jf; 
4.  
5.     JTree tree; 
6.     //上面JTree对象对应的model 
7.     DefaultTreeModel model; 
8.      
9.     //定义几个初始节点 
10.     DefaultMutableTreeNode root = new DefaultMutableTreeNode("中国");  
11.     DefaultMutableTreeNode guangdong = new DefaultMutableTreeNode("广东"); 
12.     DefaultMutableTreeNode guangxi = new DefaultMutableTreeNode("广西"); 
13.     DefaultMutableTreeNode foshan = new DefaultMutableTreeNode("佛山"); 
14.     DefaultMutableTreeNode shantou = new DefaultMutableTreeNode("汕头"); 
15.     DefaultMutableTreeNode guilin = new DefaultMutableTreeNode("桂林"); 
16.     DefaultMutableTreeNode nanning = new DefaultMutableTreeNode("南宁"); 
17.  
18.     //定义需要被拖动的TreePath 
19.     TreePath movePath; 
20.  
21.     JButton addSiblingButton = new JButton("添加兄弟节点"); 
22.     JButton addChildButton = new JButton("添加子节点"); 
23.     JButton deleteButton = new JButton("删除节点"); 
24.     JButton editButton = new JButton("编辑当前节点"); 
25.  
26.     public void init() 
27.     { 
28.         guangdong.add(foshan); 
29.         guangdong.add(shantou); 
30.         guangxi.add(guilin); 
31.         guangxi.add(nanning); 
32.         root.add(guangdong); 
33.         root.add(guangxi); 
34.          
35.         jf = new JFrame("树"); 
36.         tree = new JTree(root); 
37.         //获取JTree对应的TreeModel对象 
38.         model = (DefaultTreeModel)tree.getModel(); 
39.         //设置JTree可编辑 
40.         tree.setEditable(true); 
41.         MouseListener ml = new MouseAdapter()  
42.         { 
43.             //按下鼠标时候获得被拖动的节点 
44.             public void mousePressed(MouseEvent e) 
45.             { 
46.                 //如果需要唯一确定某个节点，必须通过TreePath来获取。 
47.                 TreePath tp = tree.getPathForLocation(e.getX(), e.getY()); 
48.                 if (tp != null) 
49.                 { 
50.                     movePath = tp; 
51.                 } 
52.             } 
53.             //鼠标松开时获得需要拖到哪个父节点 
54.             public void mouseReleased(MouseEvent e) 
55.             { 
56.                 //根据鼠标松开时的TreePath来获取TreePath 
57.                 TreePath tp = tree.getPathForLocation(e.getX(), e.getY()); 
58.  
59.                 if (tp != null && movePath != null) 
60.                 { 
61.                     //阻止向子节点拖动 
62.                     if (movePath.isDescendant(tp) && movePath != tp) 
63.                     { 
64.                         JOptionPane.showMessageDialog(jf, "目标节点是被移动节点的子节点，无法移动！",  
65.                             "非法操作", JOptionPane.ERROR_MESSAGE ); 
66.                         return; 
67.                     } 
68.                     //既不是向子节点移动，而且鼠标按下、松开的不是同一个节点 
69.                     else if (movePath != tp) 
70.                     { 
71.                         System.out.println(tp.getLastPathComponent()); 
72.                         //add方法可以先将原节点从原父节点删除，再添加到新父节点中 
73.                         ((DefaultMutableTreeNode)tp.getLastPathComponent()).add( 
74.                             (DefaultMutableTreeNode)movePath.getLastPathComponent()); 
75.                         movePath = null; 
76.                         tree.updateUI(); 
77.                     } 
78.                 } 
79.             } 
80.         }; 
81.         tree.addMouseListener(ml); 
82.  
83.         JPanel panel = new JPanel(); 
84.  
85.         addSiblingButton.addActionListener(new ActionListener() 
86.         { 
87.             public void actionPerformed(ActionEvent event) 
88.             { 
89.                 //获取选中节点 
90.                 DefaultMutableTreeNode selectedNode 
91.                     = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent(); 
92.                 //如果节点为空，直接返回 
93.                 if (selectedNode == null) return; 
94.                 //获取该选中节点的父节点 
95.                 DefaultMutableTreeNode parent 
96.                     = (DefaultMutableTreeNode)selectedNode.getParent(); 
97.                 //如果父节点为空，直接返回 
98.                 if (parent == null) return; 
99.                 //创建一个新节点 
100.                 DefaultMutableTreeNode newNode = new DefaultMutableTreeNode("新节点"); 
101.                 //获取选中节点的选中索引 
102.                 int selectedIndex = parent.getIndex(selectedNode); 
103.                 //在选中位置插入新节点 
104.                 model.insertNodeInto(newNode, parent, selectedIndex + 1); 
105.                 //--------下面代码实现显示新节点（自动展开父节点）------- 
106.                 //获取从根节点到新节点的所有节点 
107.                 TreeNode[] nodes = model.getPathToRoot(newNode); 
108.                 //使用指定的节点数组来创建TreePath 
109.                 TreePath path = new TreePath(nodes); 
110.                 //显示指定TreePath 
111.                 tree.scrollPathToVisible(path); 
112.             } 
113.         }); 
114.         panel.add(addSiblingButton); 
115.  
116.         addChildButton.addActionListener(new ActionListener() 
117.         { 
118.             public void actionPerformed(ActionEvent event) 
119.             { 
120.                 //获取选中节点 
121.                 DefaultMutableTreeNode selectedNode 
122.                     = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent(); 
123.                 //如果节点为空，直接返回 
124.                 if (selectedNode == null) return; 
125.                 //创建一个新节点 
126.                 DefaultMutableTreeNode newNode = new DefaultMutableTreeNode("新节点"); 
127.                 //直接通过model来添加新节点，则无需通过调用JTree的updateUI方法 
128.                 //model.insertNodeInto(newNode, selectedNode, selectedNode.getChildCount()); 
129.                 //直接通过节点添加新节点，则需要调用tree的updateUI方法 
130.                 selectedNode.add(newNode); 
131.                 //--------下面代码实现显示新节点（自动展开父节点）------- 
132.                 TreeNode[] nodes = model.getPathToRoot(newNode); 
133.                 TreePath path = new TreePath(nodes); 
134.                 tree.scrollPathToVisible(path); 
135.                 tree.updateUI(); 
136.             } 
137.         }); 
138.         panel.add(addChildButton); 
139.  
140.         deleteButton.addActionListener(new ActionListener() 
141.         { 
142.             public void actionPerformed(ActionEvent event) 
143.             { 
144.                 DefaultMutableTreeNode selectedNode 
145.                     = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent(); 
146.                 if (selectedNode != null && selectedNode.getParent() != null) 
147.                 { 
148.                     //删除指定节点 
149.                     model.removeNodeFromParent(selectedNode); 
150.                 } 
151.             } 
152.         }); 
153.         panel.add(deleteButton); 
154.  
155.         editButton.addActionListener(new ActionListener() 
156.         { 
157.             public void actionPerformed(ActionEvent event) 
158.             { 
159.                 TreePath selectedPath = tree.getSelectionPath(); 
160.                 if (selectedPath != null) 
161.                 { 
162.                     //编辑选中节点 
163.                     tree.startEditingAtPath(selectedPath); 
164.                 } 
165.             } 
166.         }); 
167.         panel.add(editButton); 
168.  
169.         jf.add(new JScrollPane(tree)); 
170.         jf.add(panel , BorderLayout.SOUTH); 
171.         jf.pack(); 
172.         jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
173.         jf.setVisible(true); 
174.     } 
175.  
176.     public static void main(String[] args)  
177.     { 
178.         new EditJTree().init(); 
179.     } 
180. } 

public class EditJTree { JFrame jf; JTree tree; //上面JTree对象对应的model DefaultTreeModel model; //定义几个初始节点 DefaultMutableTreeNode root = new DefaultMutableTreeNode("中国"); DefaultMutableTreeNode guangdong = new DefaultMutableTreeNode("广东"); DefaultMutableTreeNode guangxi = new DefaultMutableTreeNode("广西"); DefaultMutableTreeNode foshan = new DefaultMutableTreeNode("佛山"); DefaultMutableTreeNode shantou = new DefaultMutableTreeNode("汕头"); DefaultMutableTreeNode guilin = new DefaultMutableTreeNode("桂林"); DefaultMutableTreeNode nanning = new DefaultMutableTreeNode("南宁"); //定义需要被拖动的TreePath TreePath movePath; JButton addSiblingButton = new JButton("添加兄弟节点"); JButton addChildButton = new JButton("添加子节点"); JButton deleteButton = new JButton("删除节点"); JButton editButton = new JButton("编辑当前节点"); public void init() { guangdong.add(foshan); guangdong.add(shantou); guangxi.add(guilin); guangxi.add(nanning); root.add(guangdong); root.add(guangxi); jf = new JFrame("树"); tree = new JTree(root); //获取JTree对应的TreeModel对象 model = (DefaultTreeModel)tree.getModel(); //设置JTree可编辑 tree.setEditable(true); MouseListener ml = new MouseAdapter() { //按下鼠标时候获得被拖动的节点 public void mousePressed(MouseEvent e) { //如果需要唯一确定某个节点，必须通过TreePath来获取。 TreePath tp = tree.getPathForLocation(e.getX(), e.getY()); if (tp != null) { movePath = tp; } } //鼠标松开时获得需要拖到哪个父节点 public void mouseReleased(MouseEvent e) { //根据鼠标松开时的TreePath来获取TreePath TreePath tp = tree.getPathForLocation(e.getX(), e.getY()); if (tp != null && movePath != null) { //阻止向子节点拖动 if (movePath.isDescendant(tp) && movePath != tp) { JOptionPane.showMessageDialog(jf, "目标节点是被移动节点的子节点，无法移动！", "非法操作", JOptionPane.ERROR_MESSAGE ); return; } //既不是向子节点移动，而且鼠标按下、松开的不是同一个节点 else if (movePath != tp) { System.out.println(tp.getLastPathComponent()); //add方法可以先将原节点从原父节点删除，再添加到新父节点中 ((DefaultMutableTreeNode)tp.getLastPathComponent()).add( (DefaultMutableTreeNode)movePath.getLastPathComponent()); movePath = null; tree.updateUI(); } } } }; tree.addMouseListener(ml); JPanel panel = new JPanel(); addSiblingButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent event) { //获取选中节点 DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent(); //如果节点为空，直接返回 if (selectedNode == null) return; //获取该选中节点的父节点 DefaultMutableTreeNode parent = (DefaultMutableTreeNode)selectedNode.getParent(); //如果父节点为空，直接返回 if (parent == null) return; //创建一个新节点 DefaultMutableTreeNode newNode = new DefaultMutableTreeNode("新节点"); //获取选中节点的选中索引 int selectedIndex = parent.getIndex(selectedNode); //在选中位置插入新节点 model.insertNodeInto(newNode, parent, selectedIndex + 1); //--------下面代码实现显示新节点（自动展开父节点）------- //获取从根节点到新节点的所有节点 TreeNode[] nodes = model.getPathToRoot(newNode); //使用指定的节点数组来创建TreePath TreePath path = new TreePath(nodes); //显示指定TreePath tree.scrollPathToVisible(path); } }); panel.add(addSiblingButton); addChildButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent event) { //获取选中节点 DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent(); //如果节点为空，直接返回 if (selectedNode == null) return; //创建一个新节点 DefaultMutableTreeNode newNode = new DefaultMutableTreeNode("新节点"); //直接通过model来添加新节点，则无需通过调用JTree的updateUI方法 //model.insertNodeInto(newNode, selectedNode, selectedNode.getChildCount()); //直接通过节点添加新节点，则需要调用tree的updateUI方法 selectedNode.add(newNode); //--------下面代码实现显示新节点（自动展开父节点）------- TreeNode[] nodes = model.getPathToRoot(newNode); TreePath path = new TreePath(nodes); tree.scrollPathToVisible(path); tree.updateUI(); } }); panel.add(addChildButton); deleteButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent event) { DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent(); if (selectedNode != null && selectedNode.getParent() != null) { //删除指定节点 model.removeNodeFromParent(selectedNode); } } }); panel.add(deleteButton); editButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent event) { TreePath selectedPath = tree.getSelectionPath(); if (selectedPath != null) { //编辑选中节点 tree.startEditingAtPath(selectedPath); } } }); panel.add(editButton); jf.add(new JScrollPane(tree)); jf.add(panel , BorderLayout.SOUTH); jf.pack(); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jf.setVisible(true); } public static void main(String[] args) { new EditJTree().init(); } }

最后讲下如何修饰tree的图标，主要是通过拓展TreeCellRenderer来实现，eg

[java] view plain copy print ?

1. public class ExtendsDefaultTreeCellRenderer   
2. { 
3.     JFrame jf = new JFrame("根据节点类型定义图标"); 
4.  
5.     JTree tree; 
6.     //定义几个初始节点 
7.     DefaultMutableTreeNode root = new DefaultMutableTreeNode( 
8.         new NodeData(DBObjectType.ROOT , "数据库导航"));  
9.     DefaultMutableTreeNode salaryDb = new DefaultMutableTreeNode( 
10.         new NodeData(DBObjectType.DATABASE , "公司工资数据库")); 
11.     DefaultMutableTreeNode customerDb = new DefaultMutableTreeNode( 
12.         new NodeData(DBObjectType.DATABASE , "公司客户数据库")); 
13.     //定义salaryDb的两个子节点 
14.     DefaultMutableTreeNode employee = new DefaultMutableTreeNode( 
15.         new NodeData(DBObjectType.TABLE , "员工表")); 
16.     DefaultMutableTreeNode attend = new DefaultMutableTreeNode( 
17.         new NodeData(DBObjectType.TABLE , "考勤表")); 
18.     //定义customerDb的一个子节点 
19.     DefaultMutableTreeNode contact = new DefaultMutableTreeNode( 
20.         new NodeData(DBObjectType.TABLE , "联系方式表")); 
21.  
22.     //定义employee的三个子节点 
23.     DefaultMutableTreeNode id = new DefaultMutableTreeNode( 
24.         new NodeData(DBObjectType.INDEX , "员工ID")); 
25.     DefaultMutableTreeNode name = new DefaultMutableTreeNode( 
26.         new NodeData(DBObjectType.COLUMN , "姓名")); 
27.     DefaultMutableTreeNode gender = new DefaultMutableTreeNode( 
28.         new NodeData(DBObjectType.COLUMN , "性别")); 
29.  
30.     public void init()throws Exception 
31.     { 
32.         //通过add方法建立树节点之间的父子关系 
33.         root.add(salaryDb); 
34.         root.add(customerDb); 
35.         salaryDb.add(employee); 
36.         salaryDb.add(attend); 
37.         customerDb.add(contact); 
38.         employee.add(id); 
39.         employee.add(name); 
40.         employee.add(gender); 
41.         //以根节点创建树 
42.         tree = new JTree(root); 
43.          
44.         //设置该JTree使用自定义的节点绘制器 
45.         tree.setCellRenderer(new MyRenderer()); 
46.      
47.         //设置是否显示根节点的“展开/折叠”图标,默认是false 
48.         tree.setShowsRootHandles(true); 
49.         //设置节点是否可见,默认是true 
50.         tree.setRootVisible(true); 
51.  
52.         //设置使用Windows风格外观 
53.         UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); 
54.         //更新JTree的UI外观 
55.         SwingUtilities.updateComponentTreeUI(tree); 
56.  
57.         jf.add(new JScrollPane(tree)); 
58.         jf.pack(); 
59.         jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
60.         jf.setVisible(true); 
61.     } 
62.  
63.     public static void main(String[] args) throws Exception 
64.     { 
65.         new ExtendsDefaultTreeCellRenderer().init(); 
66.     } 
67. } 
68. //定义一个NodeData类，用于封装节点数据 
69. class NodeData 
70. { 
71.     public int nodeType; 
72.     public String nodeData; 
73.     public NodeData(int nodeType , String nodeData) 
74.     { 
75.         this.nodeType = nodeType; 
76.         this.nodeData = nodeData; 
77.     } 
78.     public String toString() 
79.     { 
80.         return nodeData; 
81.     } 
82. } 
83. //定义一个接口，该接口里包含数据库对象类型的常量 
84. interface DBObjectType 
85. { 
86.     int ROOT = 0; 
87.     int DATABASE = 1; 
88.     int TABLE = 2; 
89.     int COLUMN = 3; 
90.     int INDEX = 4; 
91. } 
92. class MyRenderer extends DefaultTreeCellRenderer 
93. { 
94.     //初始化5个图标 
95.     ImageIcon rootIcon = new ImageIcon("icon/root.gif"); 
96.     ImageIcon databaseIcon = new ImageIcon("icon/database.gif"); 
97.     ImageIcon tableIcon = new ImageIcon("icon/table.gif"); 
98.     ImageIcon columnIcon = new ImageIcon("icon/column.gif"); 
99.     ImageIcon indexIcon = new ImageIcon("icon/index.gif"); 
100.  
101.     public Component getTreeCellRendererComponent(JTree tree, Object value, 
102.         boolean sel, boolean expanded,  boolean leaf, int row, boolean hasFocus) 
103.     { 
104.         //执行父类默认的节点绘制操作 
105.         super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus); 
106.  
107.         DefaultMutableTreeNode node = (DefaultMutableTreeNode)value; 
108.         NodeData data = (NodeData)node.getUserObject(); 
109.         //根据数据节点里的nodeType数据决定节点图标 
110.         ImageIcon icon = null; 
111.         switch(data.nodeType) 
112.         { 
113.             case DBObjectType.ROOT: 
114.                 icon = rootIcon; 
115.                 break; 
116.             case DBObjectType.DATABASE: 
117.                 icon = databaseIcon; 
118.                 break; 
119.             case DBObjectType.TABLE: 
120.                 icon = tableIcon; 
121.                 break; 
122.             case DBObjectType.COLUMN: 
123.                 icon = columnIcon; 
124.                 break; 
125.             case DBObjectType.INDEX: 
126.                 icon = indexIcon; 
127.                 break; 
128.         } 
129.         //改变图标 
130.         this.setIcon(icon); 
131.         return this; 
132.     } 
133. } 

public class ExtendsDefaultTreeCellRenderer { JFrame jf = new JFrame("根据节点类型定义图标"); JTree tree; //定义几个初始节点 DefaultMutableTreeNode root = new DefaultMutableTreeNode( new NodeData(DBObjectType.ROOT , "数据库导航")); DefaultMutableTreeNode salaryDb = new DefaultMutableTreeNode( new NodeData(DBObjectType.DATABASE , "公司工资数据库")); DefaultMutableTreeNode customerDb = new DefaultMutableTreeNode( new NodeData(DBObjectType.DATABASE , "公司客户数据库")); //定义salaryDb的两个子节点 DefaultMutableTreeNode employee = new DefaultMutableTreeNode( new NodeData(DBObjectType.TABLE , "员工表")); DefaultMutableTreeNode attend = new DefaultMutableTreeNode( new NodeData(DBObjectType.TABLE , "考勤表")); //定义customerDb的一个子节点 DefaultMutableTreeNode contact = new DefaultMutableTreeNode( new NodeData(DBObjectType.TABLE , "联系方式表")); //定义employee的三个子节点 DefaultMutableTreeNode id = new DefaultMutableTreeNode( new NodeData(DBObjectType.INDEX , "员工ID")); DefaultMutableTreeNode name = new DefaultMutableTreeNode( new NodeData(DBObjectType.COLUMN , "姓名")); DefaultMutableTreeNode gender = new DefaultMutableTreeNode( new NodeData(DBObjectType.COLUMN , "性别")); public void init()throws Exception { //通过add方法建立树节点之间的父子关系 root.add(salaryDb); root.add(customerDb); salaryDb.add(employee); salaryDb.add(attend); customerDb.add(contact); employee.add(id); employee.add(name); employee.add(gender); //以根节点创建树 tree = new JTree(root); //设置该JTree使用自定义的节点绘制器 tree.setCellRenderer(new MyRenderer()); //设置是否显示根节点的“展开/折叠”图标,默认是false tree.setShowsRootHandles(true); //设置节点是否可见,默认是true tree.setRootVisible(true); //设置使用Windows风格外观 UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); //更新JTree的UI外观 SwingUtilities.updateComponentTreeUI(tree); jf.add(new JScrollPane(tree)); jf.pack(); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jf.setVisible(true); } public static void main(String[] args) throws Exception { new ExtendsDefaultTreeCellRenderer().init(); } } //定义一个NodeData类，用于封装节点数据 class NodeData { public int nodeType; public String nodeData; public NodeData(int nodeType , String nodeData) { this.nodeType = nodeType; this.nodeData = nodeData; } public String toString() { return nodeData; } } //定义一个接口，该接口里包含数据库对象类型的常量 interface DBObjectType { int ROOT = 0; int DATABASE = 1; int TABLE = 2; int COLUMN = 3; int INDEX = 4; } class MyRenderer extends DefaultTreeCellRenderer { //初始化5个图标 ImageIcon rootIcon = new ImageIcon("icon/root.gif"); ImageIcon databaseIcon = new ImageIcon("icon/database.gif"); ImageIcon tableIcon = new ImageIcon("icon/table.gif"); ImageIcon columnIcon = new ImageIcon("icon/column.gif"); ImageIcon indexIcon = new ImageIcon("icon/index.gif"); public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus) { //执行父类默认的节点绘制操作 super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus); DefaultMutableTreeNode node = (DefaultMutableTreeNode)value; NodeData data = (NodeData)node.getUserObject(); //根据数据节点里的nodeType数据决定节点图标 ImageIcon icon = null; switch(data.nodeType) { case DBObjectType.ROOT: icon = rootIcon; break; case DBObjectType.DATABASE: icon = databaseIcon; break; case DBObjectType.TABLE: icon = tableIcon; break; case DBObjectType.COLUMN: icon = columnIcon; break; case DBObjectType.INDEX: icon = indexIcon; break; } //改变图标 this.setIcon(icon); return this; } }

原文链接：http://blog.youkuaiyun.com/terryzero/article/details/3828045