休眠空间-在X公里半径内查询？

看到 这个资源
的“空间查询”教程，其中包含特殊的方言和JTS库（开放源代码）。

基本上，您可以执行以下操作（从引用的页面复制/粘贴）：

import com.vividsolutions.jts.geom.Geometry;import com.vividsolutions.jts.geom.Point;import com.vividsolutions.jts.io.ParseException;import com.vividsolutions.jts.io.WKTReader;import util.JPAUtil;import javax.persistence.EntityManager;import javax.persistence.Query;import java.util.Date;import java.util.List;

.......

private List find(String wktFilter) {    Geometry filter = wktToGeometry(wktFilter);    EntityManager em = JPAUtil.createEntityManager();    em.getTransaction().begin();    Query query = em.createQuery("select e from Event e where within(e.location, :filter) = true", Event.class);    query.setParameter("filter", filter);    return query.getResultList();}private Geometry wktToGeometry(String wktPoint) {    WKTReader fromText = new WKTReader();    Geometry geom = null;    try {        geom = fromText.read(wktPoint);    } catch (ParseException e) {        throw new RuntimeException("Not a WKT string:" + wktPoint);    }    return geom;}

有关生成圆的信息，请参见此资源（搜索“弧，圆和曲线”）。再次从那里复制/粘贴：

//this method replaces the above wktToGeometry() methodprivate static Geometry createCircle(double x, double y, final double RADIUS) {  GeometricShapeFactory shapeFactory = new GeometricShapeFactory();  shapeFactory.setNumPoints(32);  shapeFactory.setCentre(new Coordinate(x, y));//there are your coordinates  shapeFactory.setSize(RADIUS * 2);//this is how you set the radius  return shapeFactory.createCircle();}

此外，您始终拥有一种解决方法，其中可以添加一些其他字段（使用映射

insertable=false,updatable=false

org.hibernate.spatial.GeometryType