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}