如何为GeoJSON配置Spring Boot实体？

Question

我想使用Spring Boot和JPA将GeoJSON保存到数据库

JSON对象示例：

    {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "type": "polyline"
      },
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [
            21.011127,
            52.230914
          ],
          [
            21.013166,
            52.229978
          ],
          [
            21.011331,
            52.22911
          ],
          [
            21.00845,
            52.228953
          ],
          [
            21.009062,
            52.230011
          ],
          [
            21.009513,
            52.230287
          ]
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "type": "polyline"
      },
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [
            21.022489,
            52.226406
          ],
          [
            21.023004,
            52.228995
          ],
          [
            21.018069,
            52.230007
          ],
          [
            21.018755,
            52.225618
          ],
          [
            21.016202,
            52.22454
          ],
          [
            21.013906,
            52.226735
          ]
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "type": "polyline"
      },
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [
            21.013627,
            52.232005
          ],
          [
            21.018165,
            52.231933
          ],
          [
            21.019228,
            52.232537
          ],
          [
            21.019989,
            52.232925
          ],
          [
            21.019109,
            52.233201
          ]
        ]
      }
    }
  ]
}

我试图使用@ElementCollection和@Embedded配置实体。

GeoJson实体：

@Getter
@Setter
@ToString
@RequiredArgsConstructor
@Entity
public class GeoJson {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String type;
    @ElementCollection(targetClass = Feature.class)
    private List<Feature> features;
}

特点：

@Getter
@Setter
@ToString
@RequiredArgsConstructor
@Embeddable
public class Feature {
    private String type;
    @Embedded
    private Properties properties;
    @Embedded
    private Geometry geometry;
}

属性：

@Getter
@Setter
@ToString
@RequiredArgsConstructor
@Embeddable
public class Properties {
    private String type;
}

几何：

@Getter
@Setter
@ToString
@RequiredArgsConstructor
@Embeddable
public class Geometry {
    private String type;
    @ElementCollection(targetClass = Coordinate.class)
    private List<Coordinate> coordinates;
}

坐标：

@Getter
@Setter
@ToString
@RequiredArgsConstructor
@Embeddable
public class Coordinate {
    private BigDecimal lat;
    private BigDecimal lng;
}

此配置出现错误：

调用init方法失败；嵌套的异常是javax。坚持不懈PersistenceException:[PersistenceUnit:default]无法构建Hibernate SessionFactory；嵌套异常为org。冬眠MappingException：无法确定java的类型。util。在表中列出：geo_json_特性，用于org的列：[org.hibernate.mapping.Column（coordinates）]。springframework。豆。工厂支持AbstractAutowireCapableBeanFactory。initializeBean（AbstractAutowireCapableBeanFactory.java:1804）~[spring-beans-5.3.15.jar:5.3.15]

我尝试了其他映射方法，如@ManytoOne或@Manyto多国，但都不起作用。如何配置GeoJson实体以持久化？也许我应该在两个ElementCollection中添加@CollsionTable注释，但我不知道如何正确执行

Answer 1

您可以使用geotools库，它处理需要在pom中添加所需依赖项的几何体类型。xml以下是依赖项：

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-spatial</artifactId>
        <version>${hibernate.version}</version>
    </dependency>
    <dependency>
        <groupId>org.n52.jackson</groupId>
        <artifactId>jackson-datatype-jts</artifactId>
        <version>1.2.10</version>
    </dependency>
    <dependency>
        <groupId>org.geotools</groupId>
        <artifactId>gt-geojsondatastore</artifactId>
        <version>26.4</version>
    </dependency>

试试这段代码，你可以从geojson文件中获得几何图形：

       File inFile = new File("yourpath/file.geojson");
        var geojsonStore = new GeoJSONDataStore(inFile);
        SimpleFeatureSource source = geojsonStore.getFeatureSource();
        SimpleFeatureCollection features = source.getFeatures();
        var iterator = features.features();
        while (iterator.hasNext()) {
            // copy the contents of each feature and transform the geometry
            SimpleFeature feature = iterator.next();
            System.out.println(feature.getAttributes());

        }