試圖序列JTS點 - 此方法不支持的GeometryCollection參數

Question

我試圖使用JTS庫，我在與序列化有一個點屬性的類一個奇怪的問題。

import java.io.IOException; 
import java.io.Serializable; 

import com.owlike.genson.Genson; 
import com.owlike.genson.TransformationException; 
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 TestJTS implements Serializable { 

    /** 
    * 
    */ 
    private static final long serialVersionUID = 7778701490986272036L; 
    protected Point point = null; 

    public TestJTS() { 
     super(); 
    } 

    /** 
    * @param args 
    */ 
    public static void main(String[] args) { 

     TestJTS test = new TestJTS(); 
     GeometryFactory gf = new GeometryFactory(new PrecisionModel(), 4326); 
     Coordinate coordinate = new Coordinate(10.0, 100.1); 
     Point point = gf.createPoint(coordinate); 
     test.setPoint(point); 

     System.out.println("Point: " + test.getPoint()); 

     Genson genson = new Genson(); 
     try { 
      String json = genson.serialize(test); 
      System.out.println(json); 

     } catch (TransformationException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 

    public Point getPoint() { 
     return point; 
    } 

    public void setPoint(Point point) { 
     this.point = point; 
    } 
} 

這個最小的例子給我例外，但我不明白爲什麼。我的代碼錯了嗎？我是否對如何使用JTS庫做出了錯誤的假設？

Point: POINT (10 100.1) 
com.owlike.genson.TransformationException: Could not serialize property 'point' from class TestJTS 
    at com.owlike.genson.reflect.PropertyAccessor.couldNotSerialize(PropertyAccessor.java:48) 
    at com.owlike.genson.reflect.PropertyAccessor.serialize(PropertyAccessor.java:31) 
    at com.owlike.genson.reflect.BeanDescriptor.serialize(BeanDescriptor.java:87) 
    at com.owlike.genson.convert.NullConverter$NullConverterWrapper.serialize(NullConverter.java:51) 
    at com.owlike.genson.Genson.serialize(Genson.java:341) 
    at com.owlike.genson.Genson.serialize(Genson.java:222) 
    at TestJTS.main(TestJTS.java:40) 
Caused by: com.owlike.genson.TransformationException: Could not serialize property 'boundary' from class com.vividsolutions.jts.geom.Point 
    at com.owlike.genson.reflect.PropertyAccessor.couldNotSerialize(PropertyAccessor.java:48) 
    at com.owlike.genson.reflect.PropertyAccessor.serialize(PropertyAccessor.java:31) 
    at com.owlike.genson.reflect.BeanDescriptor.serialize(BeanDescriptor.java:87) 
    at com.owlike.genson.convert.NullConverter$NullConverterWrapper.serialize(NullConverter.java:51) 
    at com.owlike.genson.convert.CircularClassReferenceConverterFactory$CircularConverter.serialize(CircularClassReferenceConverterFactory.java:30) 
    at com.owlike.genson.reflect.PropertyAccessor.serialize(PropertyAccessor.java:29) 
    ... 5 more 
Caused by: com.owlike.genson.TransformationRuntimeException: Could not access value of property named 'boundary' using accessor public abstract com.vividsolutions.jts.geom.Geometry com.vividsolutions.jts.geom.Geometry.getBoundary() from class com.vividsolutions.jts.geom.Geometry 
    at com.owlike.genson.reflect.PropertyAccessor.couldNotAccess(PropertyAccessor.java:42) 
    at com.owlike.genson.reflect.PropertyAccessor$MethodAccessor.access(PropertyAccessor.java:72) 
    at com.owlike.genson.reflect.PropertyAccessor.serialize(PropertyAccessor.java:26) 
    at com.owlike.genson.reflect.BeanDescriptor.serialize(BeanDescriptor.java:87) 
    at com.owlike.genson.convert.NullConverter$NullConverterWrapper.serialize(NullConverter.java:51) 
    at com.owlike.genson.convert.CircularClassReferenceConverterFactory$CircularConverter.serialize(CircularClassReferenceConverterFactory.java:30) 
    at com.owlike.genson.reflect.PropertyAccessor.serialize(PropertyAccessor.java:29) 
    ... 9 more 
Caused by: java.lang.reflect.InvocationTargetException 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:601) 
    at com.owlike.genson.reflect.PropertyAccessor$MethodAccessor.access(PropertyAccessor.java:66) 
    ... 14 more 
Caused by: java.lang.IllegalArgumentException: This method does not support GeometryCollection arguments 
    at com.vividsolutions.jts.geom.Geometry.checkNotGeometryCollection(Geometry.java:1782) 
    at com.vividsolutions.jts.geom.GeometryCollection.getBoundary(GeometryCollection.java:154) 
    ... 19 more 

Answer 1

這裏的問題是，Genson試圖基於其getter方法和公共領域你的觀點序列化，這似乎並沒有與JTS拌勻。最好的解決方案是編寫一個將使用工廠構建的自定義轉換器，這允許您將一些內容委託給現有機制。

class JTSPointConverterFactory implements Factory<Converter<Point>> { 

    @Override public Converter<Point> create(Type type, 
      Genson genson) { 
     final Converter<Coordinate> coordianteConverter = genson.provideConverter(Coordinate.class); 

     Converter<Point> pointConverter = new Converter<Point>() { 
      private final GeometryFactory gf = new GeometryFactory(new PrecisionModel(), 4326); 

      @Override public void serialize(Point point, ObjectWriter writer, 
        Context ctx) throws TransformationException, IOException { 
       Coordinate coordinate = point.getCoordinate(); 

       writer.beginObject() 
         .writeName("x").writeValue(coordinate.x) 
         .writeName("y").writeValue(coordinate.y); 

       if (!Double.isNaN(coordinate.z)) 
        writer.writeName("z").writeValue(coordinate.z); 

       writer.endObject(); 
      } 

      @Override public Point deserialize(ObjectReader reader, Context ctx) 
        throws TransformationException, IOException { 
       // just delegate to gensons Coordiante converter the deserialization 
       return gf.createPoint(coordianteConverter.deserialize(reader, ctx)); 
      } 
     }; 
     return pointConverter; 
    } 

} 

// now register your factory 
Genson genson = new Genson.Builder() 
          .withConverterFactory(new JTSPointConverterFactory()) 
          .create(); 

genson.serialize(testJts);