The SHP format is a vector data format used to store geographic information system (GIS) data.
SHP files consist of a series of ordered files. The shp files we export include .shp, .shx, .dbf, .prj and .fix files.
- .shp (shape) file: stores vector map data and records the spatial location information of each feature.
- .shx (shape index) file: It is an index file, used to store the location of elements in the .shp file to speed up data access.
- .dbf (dBase) file: stores attribute information of vector data, such as the name, type and other information of each point on the map.
- .prj (projection) file: It is a map coordinate system file, which contains map projection information.
- .fix file: fid index file
The code for exporting shp files is implemented as follows:
<properties>
<geotools-version>28.2</geotools-version>
</properties>
<dependencies>
<!-- geotools-->
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-main</artifactId>
<version>${geotools-version}</version>
</dependency>
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-shapefile</artifactId>
<version>${geotools-version}</version>
</dependency>
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-metadata</artifactId>
<version>${geotools-version}</version>
</dependency>
</dependencies>
<!-- geotools warehouse-->
<repositories>
<repository>
<id>osgeo</id>
<name>Open Source Geospatial Foundation Repository</name>
<url>https://repo.osgeo.org/repository/release/</url>
</repository>
<repository>
<id>osgeo-snapshot</id>
<name>OSGeo Snapshot Repository</name>
<url>https://repo.osgeo.org/repository/snapshot/</url>
</repository>
</repositories>
</project>
public class ExportShp {<!-- -->
/**
* Export shp file
*
* @param dataPropertiesList property list {property name: property value}
* @param fileName export shp file name
* @param geomType geometry type
*/
private static void exportShp(List<Map<String, Object>> dataPropertiesList, String fileName, String geomType) {<!-- -->
//Create and save shp folder
String saveFolder = "D:/workspace/vector/vector/exportShp/";
File dir = new File(saveFolder);
if (!dir.exists()) {<!-- -->
FileUtil.mkdir(dir);
}
//shp file path
String shpFileName = fileName + ".shp";
String fileUrl = saveFolder + shpFileName;
File file = new File(fileUrl);
FeatureWriter<SimpleFeatureType, SimpleFeature> writer = null;
ShapefileDataStore ds = null;
try {<!-- -->
Map<String, Serializable> params = new HashMap<>();
params.put(ShapefileDataStoreFactory.URLP.key, file.toURI().toURL());
ds = (ShapefileDataStore) new ShapefileDataStoreFactory().createNewDataStore(params);
//Define graphic information and attribute information
SimpleFeatureTypeBuilder tb = new SimpleFeatureTypeBuilder();
//Set the coordinate system
CoordinateReferenceSystem crs84 = CRS.decode("EPSG:4326", true);
tb.setCRS(crs84);
//Set file name
tb.setName(fileName);
//Define the plot attribute name of the exported shp file
String geomProperty = "the_geom";
String idProperty = "ID";
String nameProperty = "name";
String descriptionProperty = "desc";
//Set graphics type
if ("Polygon".equals(geomType)) {<!-- -->
tb.add(geomProperty, Polygon.class);
} else if ("MultiPolygon".equals(geomType)) {<!-- -->
tb.add(geomProperty, MultiPolygon.class);
} else if ("Point".equals(geomType)) {<!-- -->
tb.add(geomProperty, Point.class);
} else if ("MultiPoint".equals(geomType)) {<!-- -->
tb.add(geomProperty, MultiPoint.class);
} else if ("LineString".equals(geomType)) {<!-- -->
tb.add(geomProperty, LineString.class);
} else if ("MultiLineString".equals(geomType)) {<!-- -->
tb.add(geomProperty, MultiLineString.class);
} else {<!-- -->
throw new BizIllegalArgumentException("There is no such type in Geometry: " + geomType);
}
//Set the corresponding attribute type
tb.add(idProperty, String.class);
tb.add(nameProperty, String.class);
tb.add(descriptionProperty, String.class);
//Set the default geometry
tb.setDefaultGeometry(geomProperty);
//create
ds.createSchema(tb.buildFeatureType());
ds.setCharset(StandardCharsets.UTF_8);
//Set Writer
writer = ds.getFeatureWriter(ds.getTypeNames()[0],
Transaction.AUTO_COMMIT);
SimpleFeature feature;
for (Map<String, Object> map : dataPropertiesList) {<!-- -->
feature = writer.next();
//Attribute assignment geometry should be assigned in wkt format
feature.setAttribute(geomProperty, new WKTReader().read((MapUtil.getStr(map, "geometry"))));
feature.setAttribute(idProperty, MapUtil.getStr(map, idProperty));
feature.setAttribute(nameProperty, MapUtil.getStr(map, "name"));
String description = MapUtil.getStr(map, "Description");
if (CharSequenceUtil.isNotBlank(description)) {<!-- -->
feature.setAttribute(descriptionProperty, description);
}
}
writer.write();
} catch (IOException | FactoryException | ParseException e) {<!-- -->
e.printStackTrace();
} finally {<!-- -->
//Close the relevant stream
try {<!-- -->
if (writer != null) {<!-- -->
writer.close();
}
} catch (IOException e) {<!-- -->
e.printStackTrace();
}
if (ds != null) {<!-- -->
ds.dispose();
}
}
}
public static void main(String[] args) {<!-- -->
List<Map<String,Object>> propertyList = new ArrayList<>();
for (int i = 0; i < 3; i + + ) {<!-- -->
Map<String,Object> map = new HashMap<>();
map.put("ID", i);
map.put("name", "test" + i);
map.put("Description", "Test shp export" + i);
map.put("geometry", "MULTILINESTRING ((114.0888763800001 22.549298400000055, 114.0897166200001 22.54931240800005, 114.09006708000004 22.54931825 0000056, 114.09104754000009 22.549328150000065))");
propertyList.add(map);
}
exportShp(propertyList, "test", "MultiLineString");
}
}
The exported file is as follows:
