【MyBatis】MyBatis使用TypeHandle对Geometry进行操作

0.项目环境

0.1 build.gradle.kts文件重点如下

repositories {
    // 第一步的,需要加入下面两个仓库,且需要放在最前面,因为有个依赖aliyun下载不下来
    maven { url = uri("https://repo.osgeo.org/repository/release/") }
    maven { url = uri("https://repo.osgeo.org/repository/snapshot/") }
    maven { url = uri("https://maven.aliyun.com/repository/public/") }
    mavenCentral()
}

dependencies {
    // 数据库相关用到的依赖如下
    implementation("com.baomidou:mybatis-plus-boot-starter:3.5.4")
    implementation("org.jetbrains:annotations:24.0.0")
    runtimeOnly("org.postgresql:postgresql")
    // geom工具类
    implementation("net.postgis:postgis-jdbc:2021.1.0")
    implementation("org.geotools:gt-geometry:24.7")
    implementation("org.geotools:gt-geojson:24.7")
}

1.实现一个自己的BaseTypeHandler

package com.kmlpkj.smart.village.api.configuration.mybatis.handler

import cn.hutool.extra.spring.SpringUtil
import com.fasterxml.jackson.databind.ObjectMapper
import org.apache.ibatis.type.BaseTypeHandler
import org.apache.ibatis.type.JdbcType
import org.geotools.geojson.geom.GeometryJSON
import org.locationtech.jts.io.ByteOrderValues
import org.locationtech.jts.io.WKBReader
import org.locationtech.jts.io.WKBWriter
import org.postgresql.util.PGobject
import org.slf4j.LoggerFactory
import java.sql.CallableStatement
import java.sql.PreparedStatement
import java.sql.ResultSet


/**
 * Geom字段格式化处理
 */
class GeomTypeHandler : BaseTypeHandler<Any>() {

    companion object {
        private val log = LoggerFactory.getLogger(this::class.java)
    }

    override fun getNullableResult(rs: ResultSet?, columnName: String?): Any? {
        rs?.getString(columnName)?.let {
            return convert(it)
        }
        return null
    }

    override fun getNullableResult(rs: ResultSet?, columnIndex: Int): Any? {
        rs?.getString(columnIndex)?.let {
            return convert(it)
        }
        return null
    }

    override fun getNullableResult(cs: CallableStatement?, columnIndex: Int): Any? {
         cs?.getString(columnIndex)?.let {
            return convert(it)
        }
        return null
    }

    override fun setNonNullParameter(ps: PreparedStatement?, i: Int, parameter: Any?, jdbcType: JdbcType?) {
        val om = SpringUtil.getBean(ObjectMapper::class.java)
        try {
            val geom = GeometryJSON(10).read(om.readTree(parameter.toString()).toPrettyString())
            geom.srid = 4490
            val writer = WKBWriter(2, ByteOrderValues.BIG_ENDIAN, true)
            val bytes = writer.write(geom)
            val s1 = WKBWriter.toHex(bytes)
            ps?.setObject(i, PGobject().also {
                it.type = "geometry"
                it.value = s1
            })
        } catch (e: Exception) {
            e.printStackTrace()
            throw RuntimeException("转换geom字段失败")
        }
    }

    private fun convert(wkb: String): Any {
        try {
            val geom = WKBReader().read(WKBReader.hexToBytes(wkb))
            val str = GeometryJSON(10).toString(geom)
            return SpringUtil.getBean(ObjectMapper::class.java).readTree(str)
        } catch (e: Exception) {
            e.printStackTrace()
            throw RuntimeException("转换geom字段失败")
        }
    }
}

2.在对应的实体上加入TypeHandler

// 第一 需要在@TableName注解中启用autoResultMap = true
// 第二 需要在@TableField注解中指定typeHandler

@TableName(value = "xx", autoResultMap = true)
class Grid {
    @TableField(value = "geom", typeHandler = GeomTypeHandler::class)
    var geom: Any? = null
}

3.在对于Mapper中指定TypeHandler

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.kmlpkj.smart.village.api.mapper.GridMapper">
    <resultMap id="BaseResultMap" type="xxx">
        <!-- 在typeHandler中指定我们的文件,这里是不是必须得我没尝试,但是我都加上了 -->
        <result column="geom" jdbcType="OTHER" property="geom" typeHandler="xxx.GeomTypeHandler"/>
    </resultMap>
</mapper>

4.对应的格式说明

4.1 入参格式

入参格式如下,只需要传GeoJSON格式中的具体的geometry字段的内容即可

格式内容支持:Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon和GeometryCollection

{
  "type": "Polygon",
  "coordinates": [
    [
      [
        104.03273502416919,
        23.810639861962807
      ]
    ]
  ]
}

4.2 应用后查询格式说明

查询后的格式如下

{
  "geom": {
    "type": "Polygon",
    "coordinates": [
      [
        [
          105.3362898252,
          23.8315432677
        ]
      ]
    ]
  }
}