java实现省市区转换成树形结构

本文实例为大家分享了java实现省市区转换成树形结构的具体代码，供大家参考，具体内容如下

前言：为什我想写这篇博客呢？第一方面是记录，另一方面是分享。

1.创建数据库表

1.建表语句

CREATE TABLE `area`  (
  `AREA_CODE` varchar(16) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '区域ID',
  `AREA_NAME` varchar(512) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '区域名称',
  `SUPERIOR_CODE` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '父级代码',
  `AREA_LEVEL` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '级别',
  `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 '备注',
  `DELETE_FLAG` varchar(1) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '删除标识',
  `CREATED_BY` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '创建人',
  `CREATION_TIME` timestamp(0) NOT NULL DEFAULT CURRENT_TIMESTAMP(0) ON UPDATE CURRENT_TIMESTAMP(0) COMMENT '创建时间',
  `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 '更新时间',
  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 = '区域表' ROW_FORMAT = DYNAMIC;

SET FOREIGN_KEY_CHECKS = 1;

建表完成的table样式：

2.创建java实体

package org.labib.pojo;

import java.util.Date;

public class Area {
    //区域ID
    private String areaCode;
    //区域名称
    private String areaName;
    //父级代码
    private String superiorCode;
    //级别
    private String areaLevel;
    //排序
    private String areaSort;
    //备注
    private String remark;
    //删除标识
    private String deleteFlag;
    //创建人
    private String createdBy;
    //创建时间
    private Date creationTime;
    //更新人
    private String updatedBy;
    //更新时间
    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.创建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.创建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();
   }
}

并附上转换成树形结构的工具类：

public class ListToTree {
    public static JSONArray buildTree(JSONArray arr, String id, String pid, String Chirden) {
        //新建一个JSONArray来接收组装成树形结构的返回值
        JSONArray jsonArray = new JSONArray();
        //新建一个JSONObject对象
        JSONObject hash = new JSONObject();
        //将数组转换为object格式
        for (int i = 0; i < arr.size(); i++) {
            //获取当前的JSON对象
            JSONObject json = (JSONObject) arr.get(i);
            //把当前id作为键，当前JSON对象作为值 put回hash这个Object对象中
            //这里的put方法类似于map的put方法
            hash.put(json.getString(id), json);
        }
        //遍历结果集
        for (int j = 0; j < arr.size(); j++) {
            //单条记录
            JSONObject aVal = (JSONObject) arr.get(j);
            //在hash中取出key为单条记录中pid的值
            String pidStr = "";
            //如果父级id不等于null
            if (aVal.get(pid) != null) {
                pidStr = aVal.get(pid).toString();
            }
            //从hash这个对象中获取父级对象  parent
            JSONObject hashParent = (JSONObject) hash.get(pidStr);
            //如果记录的pid存在，则说明它有父节点，将她添加到孩子节点的集合中
            if (hashParent != null) {
                //检查是否有child属性
                if (hashParent.get(Chirden) != null) {
                    //有子节点 则先将子节点取出
                    JSONArray children = (JSONArray) hashParent.get(Chirden);
                    //然后把当前这个对象放进子节点之中
                    children.add(aVal);
                    //最后把子节点在放回父节点之中
                    hashParent.put(Chirden, children);
                } else {
                    //无子节点 则新建一个子节点
                    JSONArray children = new JSONArray();
                    //然后再把当前对象放进去
                    children.add(aVal);
                    //最后在放回父节点之中
                    hashParent.put(Chirden, children);
                }
            } else {
                jsonArray.add(aVal);
            }
        }
        return jsonArray;

    }
}

5.创建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();
    }
}

6.接口测试

测试结果：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。