1、利用場景
組織機構樹，通常會有組織機構表，其中有code(代碼),pcode(上級代碼),name(組織名稱)等字段
2、構造數據（以下數據並不是組織機構數據，而純屬本人胡編亂造的數據）
1 List<Tree<Test>> trees = new ArrayList<Tree<Test>>();
2 tests.add(new Test("0", "", "關於本人"));
3 tests.add(new Test("1", "0", "技術學習"));
4 tests.add(new Test("2", "0", "興趣"));
5 tests.add(new Test("3", "1", "JAVA"));
6 tests.add(new Test("4", "1", "oracle"));
7 tests.add(new Test("5", "1", "spring"));
8 tests.add(new Test("6", "1", "springmvc"));
9 tests.add(new Test("7", "1", "fastdfs"));
10 tests.add(new Test("8", "1", "linux"));
11 tests.add(new Test("9", "2", "騎行"));
12 tests.add(new Test("10", "2", "吃喝玩樂"));
13 tests.add(new Test("11", "2", "學習"));
14 tests.add(new Test("12", "3", "String"));
15 tests.add(new Test("13", "4", "sql"));
16 tests.add(new Test("14", "5", "ioc"));
17 tests.add(new Test("15", "5", "aop"));
18 tests.add(new Test("16", "1", "等等"));
19 tests.add(new Test("17", "2", "等等"));
20 tests.add(new Test("18", "3", "等等"));
21 tests.add(new Test("19", "4", "等等"));
22 tests.add(new Test("20", "5", "等等"));
3、源碼
Tree.java
1 package pers.kangxu.datautils.bean.tree;
2
3 import java.util.ArrayList;
4 import java.util.List;
5 import java.util.Map;
6
7 import com.alibaba.fastjson.JSON;
8
9 /**
10 * tree TODO <br>
11 *
12 * @author kangxu2 2017-1-7
13 *
14 */
15 public class Tree<T> {
16 /**
17 * 節點ID
18 */
19 private String id;
20 /**
21 * 顯示節點文本
22 */
23 private String text;
24 /**
25 * 節點狀態，open closed
26 */
27 private String state = "open";
28 /**
29 * 節點是否被選中 true false
30 */
31 private boolean checked = false;
32 /**
33 * 節點屬性
34 */
35 private List<Map<String, Object>> attributes;
36 /**
37 * 節點的子節點
38 */
39 private List<Tree<T>> children = new ArrayList<Tree<T>>();
40
41 /**
42 * 父ID
43 */
44 private String parentId;
45 /**
46 * 是否有父節點
47 */
48 private boolean isParent = false;
49 /**
50 * 是否有子節點
51 */
52 private boolean isChildren = false;
53
54 public String getId() {
55 return id;
56 }
57
58 public void setId(String id) {
59 this.id = id;
60 }
61
62 public String getText() {
63 return text;
64 }
65
66 public void setText(String text) {
67 this.text = text;
68 }
69
70 public String getState() {
71 return state;
72 }
73
74 public void setState(String state) {
75 this.state = state;
76 }
77
78 public boolean isChecked() {
79 return checked;
80 }
81
82 public void setChecked(boolean checked) {
83 this.checked = checked;
84 }
85
86 public List<Map<String, Object>> getAttributes() {
87 return attributes;
88 }
89
90 public void setAttributes(List<Map<String, Object>> attributes) {
91 this.attributes = attributes;
92 }
93
94 public List<Tree<T>> getChildren() {
95 return children;
96 }
97
98 public void setChildren(List<Tree<T>> children) {
99 this.children = children;
100 }
101
102 public boolean isParent() {
103 return isParent;
104 }
105
106 public void setParent(boolean isParent) {
107 this.isParent = isParent;
108 }
109
110 public boolean isChildren() {
111 return isChildren;
112 }
113
114 public void setChildren(boolean isChildren) {
115 this.isChildren = isChildren;
116 }
117
118 public String getParentId() {
119 return parentId;
120 }
121
122 public void setParentId(String parentId) {
123 this.parentId = parentId;
124 }
125
126 public Tree(String id, String text, String state, boolean checked,
127 List<Map<String, Object>> attributes, List<Tree<T>> children,
128 boolean isParent, boolean isChildren, String parentID) {
129 super();
130 this.id = id;
131 this.text = text;
132 this.state = state;
133 this.checked = checked;
134 this.attributes = attributes;
135 this.children = children;
136 this.isParent = isParent;
137 this.isChildren = isChildren;
138 this.parentId = parentID;
139 }
140
141 public Tree() {
142 super();
143 }
144
145 @Override
146 public String toString() {
147
148 return JSON.toJSONString(this);
149 }
150
151 }
BuildTree.java
1 package pers.kangxu.datautils.common.tree;
2
3 import java.util.ArrayList;
4 import java.util.List;
5
6 import pers.kangxu.datautils.bean.tree.Tree;
7
8 /**
9 * 構建tree
10 * TODO
11 * <br>
12 * @author kangxu2 2017-1-7
13 *
14 */
15 public class BuildTree {
16
17 /**
18 *
19 * TODO
20 * <br>
21 * @author kangxu2 2017-1-7
22 *
23 * @param nodes
24 * @return
25 */
26 public static <T> Tree<T> build(List<Tree<T>> nodes) {
27
28 if(nodes == null){
29 return null;
30 }
31 List<Tree<T>> topNodes = new ArrayList<Tree<T>>();
32
33 for (Tree<T> children : nodes) {
34
35 String pid = children.getParentId();
36 if (pid == null || "".equals(pid)) {
37 topNodes.add(children);
38
39 continue;
40 }
41
42 for (Tree<T> parent : nodes) {
43 String id = parent.getId();
44 if (id != null && id.equals(pid)) {
45 parent.getChildren().add(children);
46 children.setParent(true);
47 parent.setChildren(true);
48
49 continue;
50 }
51 }
52
53 }
54
55 Tree<T> root = new Tree<T>();
56 if (topNodes.size() == 0) {
57 root = topNodes.get(0);
58 } else {
59 root.setId("-1");
60 root.setParentId("");
61 root.setParent(false);
62 root.setChildren(true);
63 root.setChecked(true);
64 root.setChildren(topNodes);
65 root.setText("頂級節點");
66
67 }
68
69 return root;
70 }
71
72 }
BuildTreeTester.java
1 package pers.kangxu.datautils.test;
2
3 import java.util.ArrayList;
4 import java.util.List;
5
6 import pers.kangxu.datautils.bean.tree.Tree;
7 import pers.kangxu.datautils.common.tree.BuildTree;
8
9 public class BuildTreeTester {
10
11 public static void main(String[] args) {
12
13
14 List<Tree<Test>> trees = new ArrayList<Tree<Test>>();
15 List<Test> tests = new ArrayList<Test>();
16 tests.add(new Test("0", "", "關於本人"));
17 tests.add(new Test("1", "0", "技術學習"));
18 tests.add(new Test("2", "0", "興趣"));
19 tests.add(new Test("3", "1", "JAVA"));
20 tests.add(new Test("4", "1", "oracle"));
21 tests.add(new Test("5", "1", "spring"));
22 tests.add(new Test("6", "1", "springmvc"));
23 tests.add(new Test("7", "1", "fastdfs"));
24 tests.add(new Test("8", "1", "linux"));
25 tests.add(new Test("9", "2", "騎行"));
26 tests.add(new Test("10", "2", "吃喝玩樂"));
27 tests.add(new Test("11", "2", "學習"));
28 tests.add(new Test("12", "3", "String"));
29 tests.add(new Test("13", "4", "sql"));
30 tests.add(new Test("14", "5", "ioc"));
31 tests.add(new Test("15", "5", "aop"));
32 tests.add(new Test("16", "1", "等等"));
33 tests.add(new Test("17", "2", "等等"));
34 tests.add(new Test("18", "3", "等等"));
35 tests.add(new Test("19", "4", "等等"));
36 tests.add(new Test("20", "5", "等等"));
37
38 for (Test test : tests) {
39 Tree<Test> tree = new Tree<Test>();
40 tree.setId(test.getId());
41 tree.setParentId(test.getPid());
42 tree.setText(test.getText());
43
44 trees.add(tree);
45 }
46
47 Tree<Test> t = BuildTree.build(trees);
48 System.out.println(t);
49 }
50 }
51
52 class Test {
53
54 private String id;
55 private String pid;
56 private String text;
57
58 public String getId() {
59 return id;
60 }
61
62 public void setId(String id) {
63 this.id = id;
64 }
65
66 public String getPid() {
67 return pid;
68 }
69
70 public void setPid(String pid) {
71 this.pid = pid;
72 }
73
74 public String getText() {
75 return text;
76 }
77
78 public void setText(String text) {
79 this.text = text;
80 }
81
82 public Test(String id, String pid, String text) {
83 super();
84 this.id = id;
85 this.pid = pid;
86 this.text = text;
87 }
88
89 public Test() {
90 super();
91 }
92
93 @Override
94 public String toString() {
95 return "Test [id=" + id + ", pid=" + pid + ", text=" + text + "]";
96 }
97
98 }
4、運行結果
JSON數據：
{
"checked": true,
"children": [
{
"checked": false,
"children": [
{
"checked": false,
"children": [
{
"checked": false,
"children": [
{
"checked": false,
"children": [],
"id": "12",
"parent": true,
"parentId": "3",
"state": "open",
"text": "String"
},
{
"checked": false,
"children": [],
"id": "18",
"parent": true,
"parentId": "3",
"state": "open",
"text": "等等"
}
],
"id": "3",
"parent": true,
"parentId": "1",
"state": "open",
"text": "JAVA"
},
{
"checked": false,
"children": [
{
"checked": false,
"children": [],
"id": "13",
"parent": true,
"parentId": "4",
"state": "open",
"text": "sql"
},
{
"checked": false,
"children": [],
"id": "19",
"parent": true,
"parentId": "4",
"state": "open",
"text": "等等"
}
],
"id": "4",
"parent": true,
"parentId": "1",
"state": "open",
"text": "oracle"
},
{
"checked": false,
"children": [
{
"checked": false,
"children": [],
"id": "14",
"parent": true,
"parentId": "5",
"state": "open",
"text": "ioc"
},
{
"checked": false,
"children": [],
"id": "15",
"parent": true,
"parentId": "5",
"state": "open",
"text": "aop"
},
{
"checked": false,
"children": [],
"id": "20",
"parent": true,
"parentId": "5",
"state": "open",
"text": "等等"
}
],
"id": "5",
"parent": true,
"parentId": "1",
"state": "open",
"text": "spring"
},
{
"checked": false,
"children": [],
"id": "6",
"parent": true,
"parentId": "1",
"state": "open",
"text": "springmvc"
},
{
"checked": false,
"children": [],
"id": "7",
"parent": true,
"parentId": "1",
"state": "open",
"text": "fastdfs"
},
{
"checked": false,
"children": [],
"id": "8",
"parent": true,
"parentId": "1",
"state": "open",
"text": "linux"
},
{
"checked": false,
"children": [],
"id": "16",
"parent": true,
"parentId": "1",
"state": "open",
"text": "等等"
}
],
"id": "1",
"parent": true,
"parentId": "0",
"state": "open",
"text": "技術學習"
},
{
"checked": false,
"children": [
{
"checked": false,
"children": [],
"id": "9",
"parent": true,
"parentId": "2",
"state": "open",
"text": "騎行"
},
{
"checked": false,
"children": [],
"id": "10",
"parent": true,
"parentId": "2",
"state": "open",
"text": "吃喝玩樂"
},
{
"checked": false,
"children": [],
"id": "11",
"parent": true,
"parentId": "2",
"state": "open",
"text": "學習"
},
{
"checked": false,
"children": [],
"id": "17",
"parent": true,
"parentId": "2",
"state": "open",
"text": "等等"
}
],
"id": "2",
"parent": true,
"parentId": "0",
"state": "open",
"text": "興趣"
}
],
"id": "0",
"parent": false,
"parentId": "",
"state": "open",
"text": "關於本人"
}
],
"id": "-1",
"parent": false,
"parentId": "",
"state": "open",
"text": "頂級節點"
}
學習無止盡，代碼我瘋狂
原文：http://www.cnblogs.com/kangxu/p/6260755.html
