mybatisplus集成geometry实现增改功能

news2025/1/10 23:31:59

前言

在我们工作中想要实现将空间点位信息存储到数据库时,一般使用以下语句实现

INSERT INTO `test-point` ( point,text ) VALUES ( st_GeomFromText ( 'POINT(1 1)' ),'第1个点');

update `test-point` set point=st_PointFromText('POINT(5 5)') where id =10;

但是这样每次都要去编写新增与编辑的sql语句非常麻烦,体现不出mybatisplus的便捷性,所以可以增加GeometryTypeHandler在mybatisplus生成新增编辑语句时将st_GeomFromText ()函数拼接到sql语句上,更加方便快捷

一.准备工作

首先项目添加依赖:

<dependency>
    <groupId>com.vividsolutions</groupId>
    <artifactId>jts</artifactId>
    <version>1.13</version>
</dependency>

在项目中加入GeometryTypeHandler

package com.sinosoft.springbootplus.lft.business.dispatch.map.common;

import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.PrecisionModel;
import com.vividsolutions.jts.io.*;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.MappedJdbcTypes;
import org.apache.ibatis.type.MappedTypes;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

@MappedTypes({String.class})
@MappedJdbcTypes({JdbcType.OTHER})
@Slf4j
public class GeometryTypeHandler extends BaseTypeHandler<String> {


	@Override
	public void setNonNullParameter(PreparedStatement preparedStatement, int i, String s, JdbcType jdbcType) throws SQLException {
			try{
				//String转Geometry
				Geometry geo = new WKTReader(new GeometryFactory(new PrecisionModel())).read(s);
				// Geometry转WKB
				byte[] geometryBytes = new WKBWriter(2, ByteOrderValues.LITTLE_ENDIAN, false).write(geo);
				// 设置SRID为mysql默认的 0
				byte[] wkb = new byte[geometryBytes.length+4];
				wkb[0] = wkb[1] = wkb[2] = wkb[3] = 0;
				System.arraycopy(geometryBytes, 0, wkb, 4, geometryBytes.length);
				preparedStatement.setBytes(i,wkb);
			}catch (ParseException e){
				log.error("坐标转换异常：【{}】",e.getMessage(),e);
			}
		}

	@Override
	public String getNullableResult(ResultSet resultSet, String s){
		try(InputStream inputStream = resultSet.getBinaryStream(s)){
			Geometry geo = getGeometryFromInputStream(inputStream);
			if(geo != null){
				return geo.toString();
			}
		}catch(Exception e){
			log.error("坐标转换异常：【{}】",e.getMessage(),e);
		}
		return null;
	}

	@Override
	public String getNullableResult(ResultSet resultSet, int i){
		try(InputStream inputStream = resultSet.getBinaryStream(i)){
			Geometry geo = getGeometryFromInputStream(inputStream);
			if(geo != null){
				return geo.toString();
			}
		}catch(Exception e){
			log.error("坐标转换异常：【{}】",e.getMessage(),e);
		}
		return null;
	}

	@Override
	public String getNullableResult(CallableStatement callableStatement, int i) throws SQLException {
		return "";
	}
	/**
	 * 流 转 geometry
	 * */
	private  Geometry getGeometryFromInputStream(InputStream inputStream) throws Exception {

		Geometry dbGeometry = null;

		if (inputStream != null) {
			// 二进制流转成字节数组
			byte[] buffer = new byte[255];

			int bytesRead;
			ByteArrayOutputStream baos = new ByteArrayOutputStream();
			while ((bytesRead = inputStream.read(buffer)) != -1) {
				baos.write(buffer, 0, bytesRead);
			}
			// 得到字节数组
			byte[] geometryAsBytes = baos.toByteArray();
			// 字节数组小于5 异常
			if (geometryAsBytes.length < 5) {
				throw new RuntimeException("坐标异常");
			}

			//字节数组前4个字节表示srid 去掉
			byte[] sridBytes = new byte[4];
			System.arraycopy(geometryAsBytes, 0, sridBytes, 0, 4);
			boolean bigEndian = (geometryAsBytes[4] == 0x00);
			// 解析srid
			int srid = 0;
			if (bigEndian) {
				for (byte sridByte : sridBytes) {
					srid = (srid << 8) + (sridByte & 0xff);
				}
			} else {
				for (int i = 0; i < sridBytes.length; i++) {
					srid += (sridBytes[i] & 0xff) << (8 * i);
				}
			}

			WKBReader wkbReader = new WKBReader();
			// WKBReader 把字节数组转成geometry对象。
			byte[] wkb = new byte[geometryAsBytes.length - 4];
			System.arraycopy(geometryAsBytes, 4, wkb, 0, wkb.length);
			dbGeometry = wkbReader.read(wkb);
			dbGeometry.setSRID(srid);
		}
		return dbGeometry;
	}
}