Geometries as GeoJson

[Jon Inazio Sanchez Martinez]

I just found ModelMapper and I've found it very useful to generate DTOs.

Anyway, when it comes to serialize objects which own a JTS Geometry data type attribute, I'd want them to be in GeoJson format.

For the time being, the following class...

import java.io.Serializable;

import javax.persistence.Entity;

import javax.persistence.FetchType;

import javax.persistence.Id;

import javax.persistence.JoinColumn;

import javax.persistence.ManyToOne;

import javax.persistence.Table;

import javax.persistence.Transient;

import com.vividsolutions.jts.geom.MultiPolygon;

import lombok.AllArgsConstructor;

import lombok.Builder;

import lombok.Data;

import lombok.EqualsAndHashCode;

import lombok.NoArgsConstructor;

@Entity

@Table(name = "municipios")

@Builder

@Data

@EqualsAndHashCode

@NoArgsConstructor

@AllArgsConstructor

public class Municipio implements Serializable {

/*

* Atributos

*/

@Transient

private static final long serialVersionUID = -2486158354849124667L;

@Id

private Integer gid;

private String codigo;

private String texto;

@ManyToOne(fetch = FetchType.LAZY)

@JoinColumn(

            name = "cod_prov", 

            referencedColumnName = "codigo"

        )

private Provincia provincia;

@ManyToOne(fetch = FetchType.LAZY)

@JoinColumn(

            name = "cod_ccaa", 

            referencedColumnName = "codigo"

        )

private ComunidadAutonoma comunidad;

}

...gets serialized as this...

"municipio": {

        "gid": 27,

        "codigo": "01036",

        "texto": "Laudio/Llodio",

        "provincia": {

            "gid": 1,

            "codigo": "01",

            "texto": "Álava",

            "texto_alt": "Araba",

            "comunidad": {

                "gid": 16,

                "codigo": "16",

                "texto": "País Vasco",

                "texto_alt": "Euskadi"

            }

        },

        "geom": "MULTIPOLYGON (((-2.9420491414616916 43.14380029306756, -2.9408165999002556 43.14430841999599, -2.939059950482368 43.141709610211024, -2.94050966386134 43.13799144046195, -2.936693413950487 43.13417138986535, -2.942182362664065 43.130752517734585, -2.943746497171919 43.126998320661244, -2.9491831049375983 43.122917261507745, -2.9568712631986553 43.11281715256084, -2.958883438671909 43.11305654097181, -2.9659615390025005 43.103108652799214, -2.9652067663290955 43.10264468267702, -2.9762492404051137 43.097150217253514, -2.9899968551814102 43.1013215781132, -2.9963369436287586 43.10706705889331, -3.0097035041930043 43.11278484125608, -3.0129149314121726 43.116877214910765, -3.017330715593204 43.116457973261085, -3.019790265011745 43.11919501110562, -3.02040901781778 43.12611504150391, -3.02393972418118 43.12847813412591, -3.025215180146138 43.13126035313113, -3.021643236846659 43.137154623532716, -3.013836762498057 43.1408026665335, -3.005568207272493 43.148466258438624, -3.0026147541242167 43.14959643860667, -2.9909328393119017 43.1625087272497, -2.9796315563151357 43.17050333013982, -2.9766664577130144 43.17485199744999, -2.9736646499823842 43.17600841462698, -2.979262791265818 43.18166902950952, -2.9742758156428035 43.18436486223879, -2.97110139733367 43.18276575229797, -2.969942290790593 43.179992017776314, -2.961893498167311 43.17338464369854, -2.957182021700495 43.17193318237574, -2.955167271064855 43.170041426431084, -2.9475444948015594 43.16848931161088, -2.955018585037522 43.157632918409604, -2.9474297891472103 43.151515433493785, -2.9420491414616916 43.14380029306756)))"

    }

I've found the following artifacts, but I don't know how to configure Model Mapper to make use of either:

<dependency>

    <groupId>org.modelmapper.extensions</groupId>

    <artifactId>modelmapper-jackson</artifactId>

    <version>${modelmapper-jackson.version}</version>

</dependency>

<dependency>

    <groupId>com.bedatadriven</groupId>

    <artifactId>jackson-datatype-jts</artifactId>

    <version>${jackson-datatype-jts.version}</version>

</dependency> 

Any hint? Thank you!

[Chun Han Hsiao]

Hi,

First, you need to create a Dto class that have structure followed the spec of GeoJson (or using https://mvnrepository.com/artifact/com.vividsolutions/jts/1.13 that already provide the GeoJson classes).

Then you can using modelmapper to map the Entity to the Dto of GeoJson. (Please check http://modelmapper.org/user-manual/property-mapping/)

After that, you can use the Jackson to serialize the Dto to json formatted text.

Jon Inazio Sanchez Martinez於 2018年1月24日星期三 UTC+8上午2時35分09秒寫道：