使用递归算法结合数据库解析成Java树形结构的代码解析

网友投稿 252 2023-04-09


使用递归算法结合数据库解析成Java树形结构的代码解析

1、准备表结构及对应的表数据

a、表结构:

create table TB_TREE

(

CID NUMBER not null,

CNAME VARCHAR2(50),

PID NUMBER //父节点

)

b、表数据:

insert into tb_tree (CID, CNAME, PID) values (1, '中国', 0);

insert into tb_tree (CID, CNAME, PID) values (2, '北京市', 1);

insert into tb_tree (CID, CNAME, PID) values (3, '广东省', 1);

insert into tb_tree (CID, CNAME, PID) values (4, '上海市', 1);

insert into tb_tree (CID, CNAME, PID) values (5, '广州市', 3);

insert into tb_tree (CID, CNAME, PID) values (6, '深圳市', 3);

insert into tb_tree (CID, CNAME, PID) values (7, '海珠区', 5);

insert into tb_tree (CID, CNAME, PID) values (8, '天河区', 5);

insert into tb_tree (CID, CNAME, PID) values (9, '福田区', 6);

insert into tb_tree (CID, CNAME, PID) values (10, '南山区', 6);

insert into tb_tree (CID, CNAME, PID) values (11, '密云县', 2);

insert into tb_tree (CID, CNAME, PID) values (12, '浦东', 4);

2、TreeNode对象,对应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、测试数据

public class TreeNodeTest {

@Test

public void loadTree() throws Exception{

System.out.println(jsonUtils.javaToJson(recursiveTree(1)));

}

/**

* 递归算法解析成树形结构

*

* @param cid

* @return

* @author jiqinlin

*/

public TreeNode recursiveTree(int cid) {

//根据cid获取节点对象(SELECT * FROM tb_tree t WHERE t.cid=?)

TreeNode node = personService.getreeNode(cid);

//查询cid下的所有子节点(SELECT * FROM tb_tree t WHERE t.pid=?)

List childTreeNodes = personService.queryTreeNode(cid);

//遍历子节点

for(TreeNode child : childTreeNodes){

TreeNode n = recursiveTree(child.getCid()); //递归

node.getNodes().add(n);

}

return node;

}

}

输出的json格式如下:

{

"cid": 1,

"nodes": [

{

"cid": 2,

"nodes": [

{

"cid": 11,

"nodes": [

],

"cname": "密云县",

"pid": 2

}

],

"cname": "北京市",

"pid": 1

},

{

"cid": 3,

"nodes": [

{

"cid": 5,

"nodes": [

{

"cid": 7,

"nodes": [

],

"cname": "海珠区",

"pid": 5

},

{

"cid": 8,

"nodes": [

],

"cname": "天河区",

"pid": 5

}

],

"cname": "广州市",

"pid": 3

},

{

"cid": 6,

"nodes": [

{

"cid": 9,

"nodes": [

],

"cname": "福田区",

"pid": 6

},

{

"cid": 10,

"nodes": [

],

"cname": "南山区",

"pid": 6

}

],

"cname": "深圳市",

"pid": 3

}

],

"cname": "广东省",

"pid": 1

},

{

"cid": 4,

"nodes": [

{

"cid": 12,

"nodes": [

],

"cname": "浦东",

"pid": 4

}

],

"cname": "上海市",

"pid": 1

}

],

"cname": "中国",

"pid": 0

}

总结

以上所述是给大家介绍的使用递归算法结合数据库解析成Java树形结构的代码解析,希望对大家有所帮助,如果大家有任何疑问请给我留言,会及时回复大家的。在此也非常感谢大家对我们网站的支持!


版权声明:本文内容由网络用户投稿,版权归原作者所有,本站不拥有其著作权,亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容,请联系我们jiasou666@gmail.com 处理,核实后本网站将在24小时内删除侵权内容。

上一篇:Spring MVC Interceptor 实现性能监控的功能代码
下一篇:Java弹簧布局管理器使用方法详解
相关文章

 发表评论

暂时没有评论,来抢沙发吧~