geojson序列化

由于项目需要使用到postgis中的空间数据, 查询返回的数据,无论是wkt还是geojson都是返回的字符串格式, 开始使用字符串返回前端,前端在序列化,这操作不优雅, 后边使用map兼容所有格式,但是发现返回的数据 数字太长了, 转为了字符串, 前端拿到的就是字符串格式的数据,还是不优雅,于是想自己写一个geojson的对象封装, 各种查询博客以后,发现ObjectMapper可以按照字段对象类型去序列化, 也是spring官方推荐,比hutool好了不止一点

自定义对象按照geojson对象定义：

@Data
@AllArgsConstructor
@NoArgsConstructor
@JsonIgnoreProperties(ignoreUnknown = true)
public class GeoJsonFeature implements Serializable {

    /**
     * 类型
     */
    private String type="FeatureCollection";
    /***
     *  features
     */
    private List<GeoFeature> features;

    /***
     * 参考系
     */
    private GeoCrs crs;

    /**
     * 图层名称
     */
    private String layerName;

    /**
     * 总条数
     */
    private long total=0;
    // 其他代码 getter and setter
}

@Data
@AllArgsConstructor
@NoArgsConstructor
@JsonInclude(JsonInclude.Include.NON_NULL)
public  class GeoFeature {
    private  String type;
    private Map<String,Object> properties=new HashMap<>();

    private GeoGeometry geometry;

    private List<GeoGeometry>  geometries;// collecton集合序列化列表
}

核心类实现，通过不同的类型实现到不同的类

@NoArgsConstructor
@Data
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY,property = "type")
@JsonSubTypes(value = {
        @JsonSubTypes.Type(value = GeoPoint.class, name = "Point"),
        @JsonSubTypes.Type(value = GeoPoint.class, name = "PointZ"),
        @JsonSubTypes.Type(value = GeoLineString.class, name = "LineString"),
        @JsonSubTypes.Type(value = GeoLineString.class, name = "LineStringZ"),
        @JsonSubTypes.Type(value = GeoPolygon.class, name = "Polygon"),
        @JsonSubTypes.Type(value = GeoPolygon.class, name = "PolygonZ"),
        @JsonSubTypes.Type(value = GeoMultiPoint.class, name = "MultiPoint"),
        @JsonSubTypes.Type(value = GeoMultiPoint.class, name = "MultiPointZ"),
        @JsonSubTypes.Type(value = GeoMultiLineString.class, name = "MultiLineString"),
        @JsonSubTypes.Type(value = GeoMultiLineString.class, name = "MultiLineStringZ"),
        @JsonSubTypes.Type(value = GeoMultiPolygon.class, name = "MultiPolygon"),
        @JsonSubTypes.Type(value = GeoMultiPolygon.class, name = "MultiPolygonZ"),
        @JsonSubTypes.Type(value = GeoGeometryCollection.class, name = "GeometryCollection"),
        @JsonSubTypes.Type(value = GeoGeometryCollection.class, name = "GeometryCollectionZ"),
})
@JsonInclude(JsonInclude.Include.NON_EMPTY)
public abstract class GeoGeometry {

    private String type;

    public String toString(){ // 重写图string，方便调试，直接序列化为json结构
        return JacksonUtil.toJsonString(this);
    }
}

piont：

@NoArgsConstructor
@AllArgsConstructor
@Data
public class GeoPoint extends GeoGeometry {
    private List<Double> coordinates;
    @Override
    public String toString() {
        return super.toString();
    }
}

line

@NoArgsConstructor
@AllArgsConstructor
@Data
public class GeoLineString extends GeoGeometry {
    private List<List<Double>> coordinates;
}

polygon

@NoArgsConstructor
@AllArgsConstructor
@Data
public class GeoPolygon extends GeoGeometry {

    private List<List<List<Double>>> coordinates;
}

其余子类类似，主要定义不同类型的数组结构，