java實(shí)現(xiàn)省市區(qū)轉(zhuǎn)換成樹形結(jié)構(gòu)

更新時(shí)間：2021年08月12日 09:47:24 作者：super小蘇打

這篇文章主要為大家詳細(xì)介紹了java實(shí)現(xiàn)省市區(qū)轉(zhuǎn)換成樹形結(jié)構(gòu)，文中示例代碼介紹的非常詳細(xì)，具有一定的參考價(jià)值，感興趣的小伙伴們可以參考一下

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.創(chuàng)建數(shù)據(jù)庫表

1.建表語句

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 '父級代碼',
  `AREA_LEVEL` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '級別',
  `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：

2.創(chuàng)建java實(shí)體

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;
    //父級代碼
    private String superiorCode;
    //級別
    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對象
            JSONObject json = (JSONObject) arr.get(i);
            //把當(dāng)前id作為鍵，當(dāng)前JSON對象作為值 put回hash這個(gè)Object對象中
            //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id不等于null
            if (aVal.get(pid) != null) {
                pidStr = aVal.get(pid).toString();
            }
            //從hash這個(gè)對象中獲取父級對象  parent
            JSONObject hashParent = (JSONObject) hash.get(pidStr);
            //如果記錄的pid存在，則說明它有父節(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

@RestController
public 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();
    }
}