java实现树状图

1.定义测试数据类 VirtualDataGenerator；

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class VirtualDataGenerator {
public static List getVirtualResult() {
List dataList = new ArrayList();

HashMap dataRecord1 = new HashMap();
dataRecord1.put("id", "112000");
dataRecord1.put("name", "廊坊银行解放道支行");
dataRecord1.put("parentId", "110000");

HashMap dataRecord2 = new HashMap();
dataRecord2.put("id", "112200");
dataRecord2.put("name", "廊坊银行三大街支行");
dataRecord2.put("parentId", "112000");

HashMap dataRecord3 = new HashMap();
dataRecord3.put("id", "112100");
dataRecord3.put("name", "廊坊银行广阳道支行");
dataRecord3.put("parentId", "112000");

HashMap dataRecord4 = new HashMap();
dataRecord4.put("id", "113000");
dataRecord4.put("name", "廊坊银行开发区支行");
dataRecord4.put("parentId", "110000");

HashMap dataRecord5 = new HashMap();
dataRecord5.put("id", "100000");
dataRecord5.put("name", "廊坊银行总行");
dataRecord5.put("parentId", "");

HashMap dataRecord6 = new HashMap();
dataRecord6.put("id", "110000");
dataRecord6.put("name", "廊坊分行");
dataRecord6.put("parentId", "100000");

HashMap dataRecord7 = new HashMap();
dataRecord7.put("id", "111000");
dataRecord7.put("name", "廊坊银行金光道支行");
dataRecord7.put("parentId", "110000");

dataList.add(dataRecord1);
dataList.add(dataRecord2);
dataList.add(dataRecord3);
dataList.add(dataRecord4);
dataList.add(dataRecord5);
dataList.add(dataRecord6);
dataList.add(dataRecord7);

return dataList;
}
}

2.定义节点类 Node；

public class Node {
/**
* 节点内容
*/
public String name;

/**
* 父节点编号
*/
public String parentId;

/**
* 孩子节点列表
*/
private Children children = new Children();

// 先序遍历，拼接JSON字符串
public String toString() {
String result = "{" + "id : '" + id + "'" + ", name : '" + name + "'";

if (children != null && children.getSize() != 0) {
result += ", children : " + children.toString();
} else {
result += ", leaf : true";
}

return result + "}";
}

// 兄弟节点横向排序
public void sortChildren() {
if (children != null && children.getSize() != 0) {
children.sortChildren();
}
}

// 添加孩子节点
public void addChild(Node node) {
this.children.addChild(node);
}
}

3.定义孩子类 Children；

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;

public class Children {

private List list = new ArrayList();

public int getSize() {
return list.size();
}

public void addChild(Node node) {
list.add(node);
}

// 拼接孩子节点的JSON字符串
public String toString() {
String result = "[";
for (Iterator it = list.iterator(); it.hasNext();) {
result += ((Node) it.next()).toString();
result += ",";
}
result = result.substring(0, result.length() - 1);
result += "]";
return result;
}

// 孩子节点排序
public void sortChildren() {
// 对本层节点进行排序
// 可根据不同的排序属性，传入不同的比较器，这里传入ID比较器
Collections.sort(list, new NodeIDComparator());
// 对每个节点的下一层节点进行排序
for (Iterator it = list.iterator(); it.hasNext();) {
((Node) it.next()).sortChildren();
}
}
}

/**
* 节点比较器
*/
class NodeIDComparator implements Comparator {
// 按照节点编号比较
public int compare(Object o1, Object o2) {
int j1 = Integer.parseInt(((Node) o1).id);
int j2 = Integer.parseInt(((Node) o2).id);
return (j1 < j2 ? -1 : (j1 == j2 ? 0 : 1));
}
}

4.最后添加测试类进行测试 Test；

import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class Test {
public static void main(String[] args) {
// 读取层次数据结果集列表
List dataList = VirtualDataGenerator.getVirtualResult();
// 节点列表（散列表，用于临时存储节点对象）
HashMap nodeList = new HashMap();
// 根节点
Node root = null;
// 根据结果集构造节点列表（存入散列表）
for (Iterator it = dataList.iterator(); it.hasNext();) {
Map dataRecord = (Map) it.next();
Node node = new Node();
node.id = (String) dataRecord.get("id");
node.name = (String) dataRecord.get("name");
node.parentId = (String) dataRecord.get("parentId");
nodeList.put(node.id, node);
}
// 构造无序的多叉树
Set entrySet = nodeList.entrySet();
for (Iterator it = entrySet.iterator(); it.hasNext();) {
Node node = (Node) ((Map.Entry) it.next()).getValue();
if (node.parentId == null || node.parentId.equals("")) {
root = node;
} else {
((Node) nodeList.get(node.parentId)).addChild(node);
}
}
// 输出无序的树形菜单的JSON字符串
System.out.println(root.toString());
// 对多叉树进行横向排序
root.sortChildren();
// 输出有序的树形菜单的JSON字符串
System.out.println(root.toString());
}
}