我正在尝试使用 GeoTools 为我正在开发的应用程序即时编写 SLD。但是尽我所能,我无法输出 SLD。
从如下所示的 SLD 开始:
<StyledLayerDescriptor xmlns="http://www.opengis.net/sld" version="1.0.0"
xsi:schemaLocation="http://www.opengis.net/sld http://schemas.opengis.net/sld/1.0.0/StyledLayerDescriptor.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<NamedLayer>
<Name>named_layer</Name>
<UserStyle>
<Name>style</Name>
<IsDefault>true</IsDefault>
<FeatureTypeStyle>
<Rule>
<PointSymbolizer>
<Graphic>
<Mark>
<WellKnownName>circle</WellKnownName>
<Fill>
<CssParameter name="fill">#00aa00</CssParameter>
</Fill>
<Stroke>
<CssParameter name="stroke">#000000</CssParameter>
<CssParameter name="stroke-width">0.15</CssParameter>
</Stroke>
</Mark>
<Size>8</Size>
</Graphic>
</PointSymbolizer>
</Rule>
</FeatureTypeStyle>
</UserStyle>
</NamedLayer>
</StyledLayerDescriptor>
我使用以下代码:
package com.example.sld;
import org.geotools.sld.SLDConfiguration;
import org.geotools.sld.bindings.SLD;
import org.geotools.styling.StyledLayerDescriptor;
import org.geotools.xml.Configuration;
import org.geotools.xml.Encoder;
import org.geotools.xml.Parser;
import org.xml.sax.SAXException;
import javax.xml.parsers.ParserConfigurationException;
import java.io.IOException;
import java.io.InputStream;
public class TestStyle {
private String style;
public TestStyle() {
Configuration config = new SLDConfiguration();
Parser parser = new Parser(config);
InputStream is = getClass().getResourceAsStream("test-sld.xml");
StyledLayerDescriptor sld = null;
try {
sld = (StyledLayerDescriptor) parser.parse(is);
} catch (SAXException e) {
e.printStackTrace();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Configuration configuration = new SLDConfiguration();
Encoder encoder = new Encoder(configuration);
encoder.setOmitXMLDeclaration(true);
try {
this.style = encoder.encodeAsString(sld, SLD.STYLEDLAYERDESCRIPTOR);
} catch (IOException e) {
e.printStackTrace();
}
this.style = new String();
}
}
SLD 解析成功。我可以在我的调试器中检查它的结构并且它被正确读取。但在编码时,生成的 SLD 为空:
<sld:StyledLayerDescriptor xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:ogc="http://www.opengis.net/ogc" xmlns:sld="http://www.opengis.net/sld" xmlns:xlink="http://www.w3.org/1999/xlink"/>
我究竟做错了什么?
(GeoTools 的版本是 20.1,遵循此处的指南:http ://docs.geotools.org/latest/userguide/library/xml/style.html#encoder )
提前致谢