一、mysql数据库示例

1、 查询窗口输入SELECT ST_AsGeoJSON(ST_GeomFromText(‘POINT(11.11111 12.22222)’));

2、 返回结果 {“type”: “Point”, “coordinates”: [11.11111, 12.22222]}

3、 type：point 表示数据类型为Point ，”coordinates”: [11.11111, 12.22222]表示X坐标为11.11111，Y坐标为12.22222

4、 mysql官方参考链接

二、 java 示例

1、引入 maven 包，应用geotools工具包

 <dependency>
    <groupId>org.geotools</groupId>
    <artifactId>gt-geojson</artifactId>
    <version>23.0</version>
</dependency>
<dependency>
    <groupId>org.locationtech.jts</groupId>
    <artifactId>jts-core</artifactId>
    <version>1.16.0</version>
</dependency>
  

Jar包下载仓库地址要单独配置

 <repositories>
      <repository>
        <id>osgeo</id>
        <name>OSGeo Release Repository</name>
        <url>
        <snapshots><enabled> false </enabled></snapshots>
        <releases><enabled>true</enabled></releases>
      </repository>
    </repositories>  

2、编写 测试用例

 /**

 * geotools官方文档地址 

 * geotools maven配置地址 

 * wkt geojson概念介绍 

 */
public class GeoJsonTest {

    @Test

    void pointTest() {

        // wkt转geoJson

        try {

            String wktPoint = "POINT(11.11111 12.22222)";

            WKT reader  reader = new WKTReader();

            Geometry geometry = reader.read(wktPoint);

            String write r writer = new StringWriter();

            GeometryJSON g = new GeometryJSON();

            g.write(geometry, writer);

            String result = writer. toString ();

            System.out.println("GeoJson结果=" + result);

        } catch (Exception e) {

            System.out.println("转换异常!" + e.toString());

        }

        // geoJson转wkt

        try {

            String geoJson = "{"type":"Point","coordinates":[11.1111,12.2222]}";

            GeometryJSON gjson = new GeometryJSON();

            Reader reader = new StringReader(geoJson);

            Geometry geometry = gjson.read(reader);

            String wkt = geometry.toText();

            System.out.println("wkt结果=" + wkt);

        } catch (IOException e) {

            System.out.println("转换异常!" + e.toString());

        }

    }

}  

3、运行结果