本文實(shí)例為大家分享了java實(shí)現(xiàn)省市區(qū)轉(zhuǎn)換成樹形結(jié)構(gòu)的具體代碼，供大家參考，具體內(nèi)容如下

前言：為什我想寫這篇博客呢？第一方面是記錄，另一方面是分享。

1.建表語(yǔ)句

CREATE TABLE `area` ( `AREA_CODE` varchar(16) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT ’區(qū)域ID’, `AREA_NAME` varchar(512) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT ’區(qū)域名稱’, `SUPERIOR_CODE` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT ’父級(jí)代碼’, `AREA_LEVEL` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT ’級(jí)別’, `AREA_SORT` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT ’排序’, `REMARK` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT ’備注’, `DELETE_FLAG` varchar(1) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT ’刪除標(biāo)識(shí)’, `CREATED_BY` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT ’創(chuàng)建人’, `CREATION_TIME` timestamp(0) NOT NULL DEFAULT CURRENT_TIMESTAMP(0) ON UPDATE CURRENT_TIMESTAMP(0) COMMENT ’創(chuàng)建時(shí)間’, `UPDATED_BY` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT ’更新人’, `UPDATE_TIME` timestamp(0) NOT NULL DEFAULT ’2020-01-01 00:00:00’ COMMENT ’更新時(shí)間’, PRIMARY KEY (`AREA_CODE`) USING BTREE, UNIQUE INDEX `UK_T_PUB_AREA_AREA_CODE`(`AREA_CODE`) USING BTREE, INDEX `IDX_T_PUB_AREA_AREA_LEVEL`(`AREA_LEVEL`) USING BTREE, INDEX `IDX_T_PUB_AREA_SUPERIOR_CODE`(`SUPERIOR_CODE`) USING BTREE) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = ’區(qū)域表’ ROW_FORMAT = DYNAMIC;SET FOREIGN_KEY_CHECKS = 1;

建表完成的table樣式：

package org.labib.pojo;import java.util.Date;public class Area { //區(qū)域ID private String areaCode; //區(qū)域名稱 private String areaName; //父級(jí)代碼 private String superiorCode; //級(jí)別 private String areaLevel; //排序 private String areaSort; //備注 private String remark; //刪除標(biāo)識(shí) private String deleteFlag; //創(chuàng)建人 private String createdBy; //創(chuàng)建時(shí)間 private Date creationTime; //更新人 private String updatedBy; //更新時(shí)間 private Date updateTime; public String getAreaCode() {return areaCode; } public void setAreaCode(String areaCode) {this.areaCode = areaCode == null ? null : areaCode.trim(); } public String getAreaName() {return areaName; } public void setAreaName(String areaName) {this.areaName = areaName == null ? null : areaName.trim(); } public String getSuperiorCode() {return superiorCode; } public void setSuperiorCode(String superiorCode) {this.superiorCode = superiorCode == null ? null : superiorCode.trim(); } public String getAreaLevel() {return areaLevel; } public void setAreaLevel(String areaLevel) {this.areaLevel = areaLevel == null ? null : areaLevel.trim(); } public String getAreaSort() {return areaSort; } public void setAreaSort(String areaSort) {this.areaSort = areaSort == null ? null : areaSort.trim(); } public String getRemark() {return remark; } public void setRemark(String remark) {this.remark = remark == null ? null : remark.trim(); } public String getDeleteFlag() {return deleteFlag; } public void setDeleteFlag(String deleteFlag) {this.deleteFlag = deleteFlag == null ? null : deleteFlag.trim(); } public String getCreatedBy() {return createdBy; } public void setCreatedBy(String createdBy) {this.createdBy = createdBy == null ? null : createdBy.trim(); } public Date getCreationTime() {return creationTime; } public void setCreationTime(Date creationTime) {this.creationTime = creationTime; } public String getUpdatedBy() {return updatedBy; } public void setUpdatedBy(String updatedBy) {this.updatedBy = updatedBy == null ? null : updatedBy.trim(); } public Date getUpdateTime() {return updateTime; } public void setUpdateTime(Date updateTime) {this.updateTime = updateTime; }}3.創(chuàng)建mapper

package org.labib.mapper;import org.labib.pojo.Area;import java.util.List;import java.util.Map;public interface AreaMapper { int deleteByPrimaryKey(String areaCode); int insert(Area record); int insertSelective(Area record); Area selectByPrimaryKey(String areaCode); int updateByPrimaryKeySelective(Area record); int updateByPrimaryKey(Area record); List<Area> queryAreaAll(); List<Map<String, String>> queryMap();}4.創(chuàng)建service

@Service('AreaService')public class AreaService { @Autowired private AreaMapper areaMapper; //修建 public String queryArea(){ List<Area> mapList = areaMapper.queryAreaAll(); JSONArray result = ListToTree.buildTree(JSONArray.parseArray(JSON.toJSONString(mapList)),'areaCode','superiorCode','children'); return result.toJSONString(); } //修建 public String queryAreaCode(){ List<Map<String, String>> mapList = areaMapper.queryMap(); JSONArray result = ListToTree.buildTree(JSONArray.parseArray(JSON.toJSONString(mapList)),'value','superiorCode','children'); return result.toJSONString(); }}

并附上轉(zhuǎn)換成樹形結(jié)構(gòu)的工具類：

public class ListToTree { public static JSONArray buildTree(JSONArray arr, String id, String pid, String Chirden) {//新建一個(gè)JSONArray來(lái)接收組裝成樹形結(jié)構(gòu)的返回值JSONArray jsonArray = new JSONArray();//新建一個(gè)JSONObject對(duì)象JSONObject hash = new JSONObject();//將數(shù)組轉(zhuǎn)換為object格式for (int i = 0; i < arr.size(); i++) { //獲取當(dāng)前的JSON對(duì)象 JSONObject json = (JSONObject) arr.get(i); //把當(dāng)前id作為鍵，當(dāng)前JSON對(duì)象作為值 put回hash這個(gè)Object對(duì)象中 //這里的put方法類似于map的put方法 hash.put(json.getString(id), json);}//遍歷結(jié)果集for (int j = 0; j < arr.size(); j++) { //單條記錄 JSONObject aVal = (JSONObject) arr.get(j); //在hash中取出key為單條記錄中pid的值 String pidStr = ''; //如果父級(jí)id不等于null if (aVal.get(pid) != null) {pidStr = aVal.get(pid).toString(); } //從hash這個(gè)對(duì)象中獲取父級(jí)對(duì)象 parent JSONObject hashParent = (JSONObject) hash.get(pidStr); //如果記錄的pid存在，則說(shuō)明它有父節(jié)點(diǎn)，將她添加到孩子節(jié)點(diǎn)的集合中 if (hashParent != null) {//檢查是否有child屬性if (hashParent.get(Chirden) != null) { //有子節(jié)點(diǎn) 則先將子節(jié)點(diǎn)取出 JSONArray children = (JSONArray) hashParent.get(Chirden); //然后把當(dāng)前這個(gè)對(duì)象放進(jìn)子節(jié)點(diǎn)之中 children.add(aVal); //最后把子節(jié)點(diǎn)在放回父節(jié)點(diǎn)之中 hashParent.put(Chirden, children);} else { //無(wú)子節(jié)點(diǎn) 則新建一個(gè)子節(jié)點(diǎn) JSONArray children = new JSONArray(); //然后再把當(dāng)前對(duì)象放進(jìn)去 children.add(aVal); //最后在放回父節(jié)點(diǎn)之中 hashParent.put(Chirden, children);} } else {jsonArray.add(aVal); }}return jsonArray; }}5.創(chuàng)建controller

@RestControllerpublic class AreaController { @Resource private AreaService areaService; @RequestMapping(value = '/area',method = RequestMethod.POST) public String queryArea() {return areaService.queryArea(); } @RequestMapping(value = '/area1',method = RequestMethod.POST) public String queryAreaDemo() {return areaService.queryAreaCode(); }}6.接口測(cè)試

測(cè)試結(jié)果：

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持好吧啦網(wǎng)。