使用遞歸算法結(jié)合數(shù)據(jù)庫解析成Java樹形結(jié)構(gòu)的代碼解析

更新時間：2017年09月04日 11:08:45 作者：Ruthless

這篇文章主要介紹了使用遞歸算法結(jié)合數(shù)據(jù)庫解析成Java樹形結(jié)構(gòu)的代碼解析的相關(guān)資料,需要的朋友可以參考下

1、準(zhǔn)備表結(jié)構(gòu)及對應(yīng)的表數(shù)據(jù)

a、表結(jié)構(gòu)：

create table TB_TREE
(
CID NUMBER not null,
CNAME VARCHAR2(50),
PID NUMBER //父節(jié)點(diǎn)
)

b、表數(shù)據(jù)：

insert into tb_tree (CID, CNAME, PID) values (1, '中國', 0);
insert into tb_tree (CID, CNAME, PID) values (2, '北京市', 1);
insert into tb_tree (CID, CNAME, PID) values (3, '廣東省', 1);
insert into tb_tree (CID, CNAME, PID) values (4, '上海市', 1);
insert into tb_tree (CID, CNAME, PID) values (5, '廣州市', 3);
insert into tb_tree (CID, CNAME, PID) values (6, '深圳市', 3);
insert into tb_tree (CID, CNAME, PID) values (7, '海珠區(qū)', 5);
insert into tb_tree (CID, CNAME, PID) values (8, '天河區(qū)', 5);
insert into tb_tree (CID, CNAME, PID) values (9, '福田區(qū)', 6);
insert into tb_tree (CID, CNAME, PID) values (10, '南山區(qū)', 6);
insert into tb_tree (CID, CNAME, PID) values (11, '密云縣', 2);
insert into tb_tree (CID, CNAME, PID) values (12, '浦東', 4);

2、TreeNode對象，對應(yīng)tb_tree

public class TreeNode implements Serializable {
private Integer cid;
private String cname;
private Integer pid;
private List nodes = new ArrayList();
public TreeNode() {
}
//getter、setter省略
}

3、測試數(shù)據(jù)

public class TreeNodeTest {
@Test
public void loadTree() throws Exception{
System.out.println(JsonUtils.javaToJson(recursiveTree(1)));
}
/**
* 遞歸算法解析成樹形結(jié)構(gòu)
*
* @param cid
* @return
* @author jiqinlin
*/
public TreeNode recursiveTree(int cid) {
//根據(jù)cid獲取節(jié)點(diǎn)對象(SELECT * FROM tb_tree t WHERE t.cid=?)
TreeNode node = personService.getreeNode(cid);
//查詢cid下的所有子節(jié)點(diǎn)(SELECT * FROM tb_tree t WHERE t.pid=?)
List childTreeNodes = personService.queryTreeNode(cid); 
//遍歷子節(jié)點(diǎn)
for(TreeNode child : childTreeNodes){
TreeNode n = recursiveTree(child.getCid()); //遞歸
node.getNodes().add(n);
}
return node;
}
}

輸出的json格式如下：

{
  "cid": 1,
  "nodes": [
    {
      "cid": 2,
      "nodes": [
        {
          "cid": 11,
          "nodes": [
          ],
          "cname": "密云縣",
          "pid": 2
        }
      ],
      "cname": "北京市",
      "pid": 1
    },
    {
      "cid": 3,
      "nodes": [
        {
          "cid": 5,
          "nodes": [
            {
              "cid": 7,
              "nodes": [
              ],
              "cname": "海珠區(qū)",
              "pid": 5
            },
            {
              "cid": 8,
              "nodes": [
              ],
              "cname": "天河區(qū)",
              "pid": 5
            }
          ],
          "cname": "廣州市",
          "pid": 3
        },
        {
          "cid": 6,
          "nodes": [
            {
              "cid": 9,
              "nodes": [
              ],
              "cname": "福田區(qū)",
              "pid": 6
            },
            {
              "cid": 10,
              "nodes": [
              ],
              "cname": "南山區(qū)",
              "pid": 6
            }
          ],
          "cname": "深圳市",
          "pid": 3
        }
      ],
      "cname": "廣東省",
      "pid": 1
    },
    {
      "cid": 4,
      "nodes": [
        {
          "cid": 12,
          "nodes": [
          ],
          "cname": "浦東",
          "pid": 4
        }
      ],
      "cname": "上海市",
      "pid": 1
    }
  ],
  "cname": "中國",
  "pid": 0
}

總結(jié)

以上所述是小編給大家介紹的使用遞歸算法結(jié)合數(shù)據(jù)庫解析成Java樹形結(jié)構(gòu)的代碼解析，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復(fù)大家的。在此也非常感謝大家對腳本之家網(wǎng)站的支持！

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