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());
  }
}

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