1、準備表結構及對應的表數據
a、表結構：
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create table TB_TREE(CID NUMBER not null,CNAME VARCHAR2(50),PID NUMBER //父節點) |
b、表數據：
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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', 5);insert into tb_tree (CID, CNAME, PID) values (8, '天河區', 5);insert into tb_tree (CID, CNAME, PID) values (9, '福田區', 6);insert into tb_tree (CID, CNAME, PID) values (10, '南山區', 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tb_tree
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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、測試數據
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public class TreeNodeTest {@Testpublic void loadTree() throws Exception{System.out.println(JsonUtils.javaToJson(recursiveTree(1)));}/**** @param cid* @return* @author jiqinlin*/public TreeNode recursiveTree(int cid) {//根據cid獲取節點對象(SELECT * FROM tb_tree t WHERE t.cid=?)TreeNode node = personService.getreeNode(cid);//查詢cid下的所有子節點(SELECT * FROM tb_tree t WHERE t.pid=?)List childTreeNodes = personService.queryTreeNode(cid); //遍歷子節點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：
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{ "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", "pid": 5 }, { "cid": 8, "nodes": [ ], "cname": "天河區", "pid": 5 } ], "cname": "廣州市", "pid": 3 }, { "cid": 6, "nodes": [ { "cid": 9, "nodes": [ ], "cname": "福田區", "pid": 6 }, { "cid": 10, "nodes": [ ], "cname": "南山區", "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
以上所述是小編給大家介紹的使用遞歸算法結合數據庫解析成Java樹形結構的代碼解析，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對服務器之家網站的支持！
原文鏈接：http://www.cnblogs.com/linjiqin/archive/2013/06/21/3148066.html
