Java使用geotools将Geometry转换为kml
最近有个需求，要求将地图要素导出成kml文件，略作研究再次整理下步骤，作为备忘。
1、引入依赖包pom.xml
14.1
org.geotools
gt-shapefile
${geotools.version}
org.geotools
gt-api
${geotools.version}
org.geotools
gt-opengis
${geotools.version}
org.geotools
gt-data
${geotools.version}
org.geotools
gt-main
${geotools.version}
org.geotools
gt-referencing
13.2
org.geotools
gt-metadata
${geotools.version}
org.geotools.xsd
gt-xsd-kml
${geotools.version}
org.geotools.xsd
gt-xsd-core
${geotools.version}
com.vividsolutions
jts
1.13
2、导出步骤
import com.vividsolutions.jts.geom.*;
import org.geotools.data.DataUtilities;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.feature.simple.SimpleFeatureTypeBuilder;
import org.geotools.kml.v22.KML;
import org.geotools.kml.v22.KMLConfiguration;
import org.geotools.referencing.crs.DefaultGeographicCRS;
import org.geotools.xml.Encoder;
import org.opengis.feature.simple.SimpleFeature;
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.List;
public class KmlUtil {
/**
* 生成wml文件
* @param wmlPath wml文件路径（包含文件名称） 如：D:\data\tmp\ceshi.kml
* @param type 图幅元素类型
* @param geometries 图幅集合
* @throws Exception
*/
public static void write2Wml(String wmlPath, String type, List geometries) throws Exception {
FileOutputStream fos = new FileOutputStream(wmlPath,true);
String str = write2WmlStr(type, geometries);
//true表示在文件末尾追加
fos.write(str.getBytes());
fos.close();
}
/**
* 生成wml文件
* @param wmlPath wml文件路径（包含文件名称） 如：D:\data\tmp\ceshi.kml
* @param type 图幅元素类型
* @param geoKey data中图幅的key
* @param attrKeys 属性key集合
* @param geomList 图幅和属性集合
* @throws Exception
*/
public static void write2Wml(String wmlPath, String type, String geoKey, List attrKeys, List> geomList) throws Exception {
FileOutputStream fos = new FileOutputStream(wmlPath,true);
String str = write2WmlStr(type, geoKey, attrKeys, geomList);
//true表示在文件末尾追加
fos.write(str.getBytes());
fos.close();
}
/**
* 生成wml格式的字符串
* @param type 图幅元素类型
* @param geometrys 图幅集合
* @return 字符串
* @throws Exception
*/
public static String write2WmlStr(String type, List geometrys) throws Exception {
ByteArrayOutputStream os = write2WmlStream(type, geometrys);
String out = os.toString().replaceAll("kml:", "");
return out;
}
/**
* 生成wml格式的字符串
* @param type 图幅元素类型
* @param geoKey data中图幅的key
* @param attrKeys 属性key集合
* @param geomList 图幅和属性集合
* @return 字符串
* @throws Exception
*/
public static String write2WmlStr(String type, String geoKey, List attrKeys, List> geomList) throws Exception {
ByteArrayOutputStream os = write2WmlStream(type, geoKey, attrKeys, geomList);
String out = os.toString().replaceAll("kml:", "");
return out;
}
/**
* 生成wml格式的字节流
* @param type 图幅元素类型
* @param geometrys 图幅元素集合
* @return 字节流
* @throws Exception
*/
public static ByteArrayOutputStream write2WmlStream(String type, List geometrys) throws Exception {
SimpleFeatureTypeBuilder tb = new SimpleFeatureTypeBuilder();
tb.setCRS(DefaultGeographicCRS.WGS84);
tb.setName("kmlfile");
if ("Polygon".equals(type)) {
tb.add("the_geom", Polygon.class);
} else if ("MultiPolygon".equals(type)) {
tb.add("the_geom", MultiPolygon.class);
} else if ("Point".equals(type)) {
tb.add("the_geom", Point.class);
} else if ("MultiPoint".equals(type)) {
tb.add("the_geom", MultiPoint.class);
} else if ("LineString".equals(type)) {
tb.add("the_geom", LineString.class);
} else if ("MultiLineString".equals(type)) {
tb.add("the_geom", MultiLineString.class);
} else {
throw new Exception("Geometry中没有该类型：" + type);
}
List features = new ArrayList<>();
for (Geometry geometry : geometrys) {
SimpleFeatureBuilder sfb = new SimpleFeatureBuilder(tb.buildFeatureType());
sfb.add(geometry);
//构建要素
SimpleFeature feature = sfb.buildFeature(null);
features.add(feature);
}
SimpleFeatureCollection fc = DataUtilities.collection(features);
Encoder encoder = new Encoder(new KMLConfiguration());
//设置编码
Charset charset = Charset.forName("utf-8");
encoder.setEncoding(charset);
encoder.setIndenting(true);
ByteArrayOutputStream os = new ByteArrayOutputStream();
encoder.encode(fc, KML.kml, os);
return os;
}
/**
* 生成wml格式的字节流
* @param type 图幅元素类型
* @param geoKey data中图幅的key
* @param attrKeys 属性key集合
* @param geomList 图幅和属性集合
* @return 字节流
* @throws Exception
*/
public static ByteArrayOutputStream write2WmlStream(String type, String geoKey, List attrKeys, List> geomList) throws Exception {
SimpleFeatureTypeBuilder tb = new SimpleFeatureTypeBuilder();
tb.setCRS(DefaultGeographicCRS.WGS84);
tb.setName("kmlfile");
if ("Polygon".equals(type)) {
tb.add("the_geom", Polygon.class);
} else if ("MultiPolygon".equals(type)) {
tb.add("the_geom", MultiPolygon.class);
} else if ("Point".equals(type)) {
tb.add("the_geom", Point.class);
} else if ("MultiPoint".equals(type)) {
tb.add("the_geom", MultiPoint.class);
} else if ("LineString".equals(type)) {
tb.add("the_geom", LineString.class);
} else if ("MultiLineString".equals(type)) {
tb.add("the_geom", MultiLineString.class);
} else {
throw new Exception("Geometry中没有该类型：" + type);
}
//设置用户属性参数
for (String key : attrKeys) {
tb.add(key, String.class);
}
List features = new ArrayList<>();
for (Map obj : geomList) {
Object geoObj = obj.get(geoKey);
if (geoObj instanceof Geometry) {
Geometry geometry = (Geometry) geoObj;
SimpleFeatureBuilder sfb = new SimpleFeatureBuilder(tb.buildFeatureType());
sfb.add(geometry);
//构建要素
SimpleFeature feature = sfb.buildFeature(null);
for (String key : obj.keySet()) {
if (!key.equals(geoKey)) {
feature.setAttribute(key, obj.get(key).toString());
}
}
features.add(feature);
} else {
throw new Exception("图幅元素集合中为geoKey:" + geoKey + "的图幅元素类型必须是Geometry");
}
}
SimpleFeatureCollection fc = DataUtilities.collection(features);
Encoder encoder = new Encoder(new KMLConfiguration());
//设置编码
Charset charset = Charset.forName("utf-8");
encoder.setEncoding(charset);
encoder.setIndenting(true);
ByteArrayOutputStream os = new ByteArrayOutputStream();
encoder.encode(fc, KML.kml, os);
return os;
}
}
3、测试
public class TestMain {
public static void main(String[] args) throws Exception {
List list = new ArrayList<>();
list.add("POLYGON ((116.21278950384274 39.90557982319698, 116.21177234433465 39.90610963061354, 116.21106912279264 39.90264172209895, 116.21399502548638 39.902612822554126, 116.21629305278306 39.905011479365406, 116.21278950384274 39.90557982319698))");
list.add("POLYGON((113.38185597038 34.54828048706,113.38224220848 34.548355588913,113.38249970055 34.548108825684,113.38237095451 34.54787279129,113.38208127594 34.547786960602,113.38185597038 34.54828048706))");
List geometryList = new ArrayList<>();
for (String str : list) {
WKTReader reader = new WKTReader();
geometryList.add(reader.read(wkt));
}
List attrKeys = new ArrayList<>();
attrKeys.add("ceshi1");
attrKeys.add("ceshi2");
attrKeys.add("ceshi3");
int i = 1;
List> geomList = new ArrayList<>();
for (String str : list) {
Map map = new HashMap<>();
map.put("geoKey", WKTUtil.wktToGeom(str));
map.put("ceshi1", "测试" + i++);
map.put("ceshi2", "测试" + i++);
map.put("ceshi3", "测试" + i++);
geomList.add(map);
}
String path1 = "D:\\data\\tmp\\测试1.kml";
String path2 = "D:\\data\\tmp\\测试2.kml";
KmlUtil.write2Wml(path1, "Polygon", geometryList);
KmlUtil.write2Wml(path2, "Polygon", "geoKey", attrKeys, geomList)
//System.out.println(str);
}
} 4、测试结果（测试1.kml和测试2.kml）
// 测试1.kml ************************************
113.38185597038,34.54828048706 113.38224220848,34.548355588913 113.38249970055,34.548108825684 113.38237095451,34.54787279129 113.38208127594,34.547786960602 113.38185597038,34.54828048706
116.21278950384274,39.90557982319698 116.21177234433465,39.90610963061354 116.21106912279264,39.90264172209895 116.21399502548638,39.902612822554126 116.21629305278306,39.905011479365406 116.21278950384274,39.90557982319698
// 测试2.kml ************************************
测试4
测试5
测试6
113.38185597038,34.54828048706 113.38224220848,34.548355588913 113.38249970055,34.548108825684 113.38237095451,34.54787279129 113.38208127594,34.547786960602 113.38185597038,34.54828048706
测试1
测试2
测试3
116.21278950384274,39.90557982319698 116.21177234433465,39.90610963061354 116.21106912279264,39.90264172209895 116.21399502548638,39.902612822554126 116.21629305278306,39.905011479365406 116.21278950384274,39.90557982319698
参考博文：
GeoJSON to KML conversion: https://gis.stackexchange.com/questions/310989/geojson-to-kml-conversion