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 {
@Testpublic 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
以上所述是小编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,小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持!