在 Spring Boot 上使用 Hibernate 映射 PostGIS 几何点字段

Question

In my PostgreSQL 9.3 + PostGIS 2.1.5 I have a table PLACE with a column coordinates of type Geometry(Point,26910) .

I want to map it to Place entity in my Spring Boot 1.1.9 web application, which uses Hibernate 4.0.0 + . Place is available with a REST repository.

Unfortunately when I GET http://localhost:8080/mywebapp/places I receive this strange JSON response :

{

  "_embedded" : {

    "venues" : [ {

      "id" : 1,

      "coordinates" : {

        "envelope" : {

          "envelope" : {

            "envelope" : {

              "envelope" : {

                "envelope" : {

                  "envelope" : {

                    "envelope" : {

                      "envelope" : {

                        "envelope" : {

                          "envelope" : {

                            "envelope" : {

                              "envelope" : {

                                "envelope" : {

                                  "envelope" : {

                                    "envelope" : {

                                      "envelope" : {

                                        "envelope" : {

                                          "envelope" : {

                                            "envelope" : {

and so on indefinetely...! Spring log doesn't help..

I'm working with this application.properties:

spring.jpa.database-platform=org.hibernate.spatial.dialect.postgis.PostgisDialect
spring.jpa.show-sql=false
spring.jpa.hibernate.ddl-auto=update

spring.datasource.url=jdbc:postgresql://192.168.1.123/mywebapp
spring.datasource.username=postgres
spring.datasource.password=mypwd
spring.datasource.driverClassName=org.postgresql.Driver

First of all, is it ok to use database-platform instead of database ? And maybe do I have to use following settings instead of the above?

spring.datasource.url=jdbc:postgresql_postGIS://192.168.1.123/mywebapp
spring.datasource.driverClassName=org.postgis.DriverWrapper

Anyway my entity is something like this:

@Entity
public class Place {
    @Id
    public int id;
    @Column(columnDefinition="Geometry")
    @Type(type="org.hibernate.spatial.GeometryType")    //"org.hibernatespatial.GeometryUserType" seems to be for older versions of Hibernate Spatial
    public com.vividsolutions.jts.geom.Point coordinates;
}

My pom.xml contains this relevant part:

<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>9.3-1102-jdbc41</version>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-spatial</artifactId>
    <version>4.3</version><!-- compatible with Hibernate 4.3.x -->
    <exclusions>
        <exclusion>
            <artifactId>postgresql</artifactId>
            <groupId>postgresql</groupId>
        </exclusion>
    </exclusions>
</dependency>

A bit strange configuration, I found it on the internet, it is the one that works best for now.

I hope that someone could help me with this mistery. :)

Answer 1

Finally I discovered that my configuration is ok and might be Jackson that cannot manage Point data type correctly. So I customized its JSON serialization and deserialization:

• add these annotations to our coordinates field:

   @JsonSerialize(using = PointToJsonSerializer.class) @JsonDeserialize(using = JsonToPointDeserializer.class)

• create such serializer:

   import java.io.IOException; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.JsonSerializer; import com.fasterxml.jackson.databind.SerializerProvider; import com.vividsolutions.jts.geom.Point; public class PointToJsonSerializer extends JsonSerializer<Point> { @Override public void serialize(Point value, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonProcessingException { String jsonValue = "null"; try { if(value != null) { double lat = value.getY(); double lon = value.getX(); jsonValue = String.format("POINT (%s %s)", lat, lon); } } catch(Exception e) {} jgen.writeString(jsonValue); } }

• create such deserializer:

   import java.io.IOException; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.DeserializationContext; import com.fasterxml.jackson.databind.JsonDeserializer; import com.vividsolutions.jts.geom.Coordinate; import com.vividsolutions.jts.geom.GeometryFactory; import com.vividsolutions.jts.geom.Point; import com.vividsolutions.jts.geom.PrecisionModel; public class JsonToPointDeserializer extends JsonDeserializer<Point> { private final static GeometryFactory geometryFactory = new GeometryFactory(new PrecisionModel(), 26910); @Override public Point deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException { try { String text = jp.getText(); if(text == null || text.length() <= 0) return null; String[] coordinates = text.replaceFirst("POINT ?\\\\(", "").replaceFirst("\\\\)", "").split(" "); double lat = Double.parseDouble(coordinates[0]); double lon = Double.parseDouble(coordinates[1]); Point point = geometryFactory.createPoint(new Coordinate(lat, lon)); return point; } catch(Exception e){ return null; } } }

Maybe you can also use this serializer and this deserializer , available here .

Answer 2

The solutions above helped me to fix the problem. I simplify it so other people can understand.

I included this library in my pom.xml:

<dependency>
  <groupId>com.bedatadriven</groupId>
  <artifactId>jackson-datatype-jts</artifactId>
  <version>2.2</version>
</dependency>

This is the POJO object I used. Then I was able to get the REST call to work without the envelope error and proper coordinates.

import com.bedatadriven.jackson.datatype.jts.serialization.GeometryDeserializer;
import com.bedatadriven.jackson.datatype.jts.serialization.GeometrySerializer;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.vividsolutions.jts.geom.Geometry;

@Entity
@Table(name = "boundary")
public class Boundary {

    private int id;
    private Geometry geometry;

    @Id
    public int getId() {
        return ogc_fid;
    }

    public void setId(int id) {
        this.id = id;
    }
    
    @JsonSerialize(using = GeometrySerializer.class)
    @JsonDeserialize(using = GeometryDeserializer.class)
    @Column(name = "geometry", columnDefinition = "Geometry")
    public Geometry getGeometry() {
        return geometry;
    }

    public void setGeometry(Geometry geometry) {
        this.geometry = geometry;
    }
}

My table had these 2 columns:

id       | integer            
geometry | geometry(Geometry,4326) | 

Answer 3

This serialization/deserialization also worked fine for me.

https://github.com/bedatadriven/jackson-datatype-jts

Answer 4

With Hibernate 5.4 and Posgis 13+ its became very easy. We can just add latest hibernate-spatial dependency

    <!-- Hibernate Spatial for storing and retrieving geometries -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-spatial</artifactId>
        <version>${hibernate.version}</version>
    </dependency>

Use latest Posgis dialect . Add in application.properties :

spring.jpa.properties.hibernate.dialect=org.hibernate.spatial.dialect.postgis.PostgisPG95Dialect

Then we can simply use JST geometry because its supported by Hibernate (see here ).

import org.locationtech.jts.geom.Point;

@Entity(name = "address")
public class Address {
 private Point location;
}

SQL to create entity table :

CREATE TABLE if not EXISTS address (location geometry);

Further JTS GeoJSON Reader and Writer can be used to translate geometries into JSON (see here )

Answer 5

The problem doesn't appear to be related to PostgreSQL. It appears that your POJO has a backreference, which means that your mapper doesn't know how to handle it. You need to explicitly define the recursive relationships so that the mapper knows when to stop. (My Goto link --> http://vard-lokkur.blogspot.com/2010/10/json-jackson-to-rescue.html )

Answer 6

If you don't want to add the annotation on all your fields that are using a Point, you can also use the @JsonComponent to register your JsonSerializer and JsonDeserializer .

@JsonComponent
public class PointSerializer extends JsonSerializer<com.vividsolutions.jts.geom.Point>{

    @Override
 public void serialize(com.vividsolutions.jts.geom.Point value, JsonGenerator gen, SerializerProvider provider) throws IOException {
     gen.writeStartObject();
     gen.writeNumberField("lat", value.getY());
     gen.writeNumberField("lon", value.getX());
     gen.writeEndObject();
 }
}