Map a PostGIS geometry point field with Hibernate

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

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 2

This serialization/deserialization also worked fine for me.

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

Answer 3

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 4

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 coodinates.

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 geomertry;

    @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 getGeomertry() {
        return geomertry;
    }

    public void setGeomertry(Geometry geomertry) {
        this.geomertry = geomertry;
    }
}

My table had these 2 columns:

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