GeoTools：WKT、GeoJson、Feature、FeatureCollection相互转换
萧宏峻
测试用例：
package top.reid.smart.geo;
import cn.hutool.json.JSONUtil;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class GeoToolsTest {
String geoJsonStr = "{\n" +
" \"type\":\"Point\",\n" +
" \"coordinates\":[105.380859375,31.57853542647338]\n" +
" }";
String geoJsonStr2 = "{\"type\":\"Feature\",\n" +
" \"properties\":{},\n" +
" \"geometry\":{\n" +
" \"type\":\"Point\",\n" +
" \"coordinates\":[105.380859375,31.57853542647338]\n" +
" }\n" +
" }";
String geoJsonStr3 = "{\n" +
" \"type\": \"FeatureCollection\",\n" +
" \"features\": [\n" +
" {\"type\":\"Feature\",\n" +
" \"properties\":{},\n" +
" \"geometry\":{\n" +
" \"type\":\"Point\",\n" +
" \"coordinates\":[105.380859375,31.57853542647338]\n" +
" }\n" +
" },\n" +
"\t\t{\"type\":\"Feature\",\n" +
" \"properties\":{},\n" +
" \"geometry\":{\n" +
" \"type\":\"Point\",\n" +
" \"coordinates\":[105.380859375,31.57853542647338]\n" +
" }\n" +
" }\n" +
" ]\n" +
"}";
String[] wktStr = new String[]{"POINT(6 10)", "LINESTRING(3 4,10 50,20 25)", "POLYGON((1 1,5 1,5 5,1 5,1 1),(2 2,2 3,3 3,3 2,2 2))",
"MULTIPOINT(3.5 5.6, 4.8 10.5)", "MULTILINESTRING((3 4,10 50,20 25),(-5 -8,-10 -8,-15 -4))", "MULTIPOLYGON(((1 1,5 1,5 5,1 5,1 1),(2 2,2 3,3 3,3 2,2 2)),((6 3,9 2,9 4,6 3)))",
"GEOMETRYCOLLECTION(POINT(4 6),LINESTRING(4 6,7 10))", "POINT ZM (1 1 5 60)", "POINT M (1 1 80)"};
@Test
void getGeometryType() {
for (String s : wktStr) {
System.out.println("Geo 几何类型：" + GeoTools.getGeometryType(s));
}
}
@Test
void isWkt() {
for (String s : wktStr) {
System.out.println("是规范的 WKT：" + GeoTools.isWkt(s));
}
}
@Test
void isNotWkt() {
for (String s : wktStr) {
System.out.println("不是规范的 WKT：" + GeoTools.isNotWkt(geoJsonStr2));
}
}
@Test
void isGeoJson() {
System.out.println("是规范的 GeoJson：" + GeoTools.isGeoJson(geoJsonStr3));
}
@Test
void isNotGeoJson() {
System.out.println("不是规范的 GeoJson：" + GeoTools.isNotGeoJson(geoJsonStr3));
}
@Test
void geoJsonToWkt() {
System.out.println("GeoJson 转 WKT：" + GeoTools.geoJsonToWkt(JSONUtil.parseObj(geoJsonStr)));
System.out.println("GeoJson 转 WKT：" + GeoTools.geoJsonToWkt(JSONUtil.parseObj(geoJsonStr2)));
System.out.println("GeoJson 转 WKT：" + GeoTools.geoJsonToWkt(JSONUtil.parseObj(geoJsonStr3)));
}
@Test
void wktToGeoJson() {
for (String s : wktStr) {
System.out.println("WKT 转 GeoJson：" + GeoTools.wktToGeoJson(s));
}
}
@Test
void wktToFeature() {
for (String s : wktStr) {
System.out.println("WKT 转 Feature：" + GeoTools.wktToFeature(s));
}
}
@Test
void wktToFeatureCollection() {
for (String s : wktStr) {
System.out.println("WKT 转 FeatureCollection：" + GeoTools.wktToFeatureCollection(s));
}
}
}
小工具：
package top.reid.smart.geo;
import cn.hutool.core.util.ArrayUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONArray;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import org.geotools.data.DataUtilities;
import org.geotools.data.collection.ListFeatureCollection;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.geojson.GeoJSONUtil;
import org.geotools.geojson.feature.FeatureJSON;
import org.geotools.geojson.geom.GeometryJSON;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.GeometryCollection;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.io.WKTReader;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import java.io.IOException;
import java.io.Reader;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.List;
/**
* <p>
* 地质工具
* </p>
*
* @Author REID
* @Blog https://blog.csdn.net/qq_39035773
* @GitHub https://github.com/BeginnerA
* @Data 2020/11/11
* @Version V1.0
**/
public class GeoTools {
private static final WKTReader READER = new WKTReader();
/**
* 要素集合根节点
*/
private static final String[] COLLECTION_TYPE = new String[]{"FeatureCollection"};
/**
* 地理要素类型
*/
private static final String[] FEATURES_TYPE = new String[]{"Feature"};
/**
* 地理数据类型
* 点、线、面、几何集合
*/
private static final String[] GEO_TYPE = new String[]{"Geometry", "Point", "LineString", "Polygon", "MultiPoint", "MultiLineString", "MultiPolygon", "GeometryCollection"};
/**
* 获取 Geo 几何类型
* @param wktStr WKT 字符串
* @return Geo 几何类型
*/
public static String getGeometryType(String wktStr) {
String type = null;
if (StrUtil.isNotEmpty(wktStr)) {
try {
Geometry read = READER.read(wktStr);
type = read.getGeometryType();
}catch (Exception e) {
System.out.println("非规范 WKT 字符串："+ e);
e.printStackTrace();
}
}
return type;
}
/**
* 是规范的 WKT
* @param wktStr WKT 字符串
* @return 是、否
*/
public static boolean isWkt(String wktStr) {
for (String s : GEO_TYPE) {
if (wktStr.toLowerCase().startsWith(s.toLowerCase())) {
return true;
}
}
return false;
}
/**
* 不是规范的 WKT
* @param wktStr WKT 字符串
* @return 是、否
*/
public static boolean isNotWkt(String wktStr) {
return !isWkt(wktStr);
}
/**
* 是规范的 GeoJson
* @param geoJsonStr GeoJson 字符串
* @return 是、否
*/
public static boolean isGeoJson(String geoJsonStr) {
try {
JSONObject jsonObject = JSONUtil.parseObj(geoJsonStr);
return isGeoJson(jsonObject);
}catch (Exception e) {
return false;
}
}
/**
* 不是规范的 GeoJson
* @param geoJsonStr GeoJson 字符串
* @return 是、否
*/
public static boolean isNotGeoJson(String geoJsonStr) {
return !isGeoJson(geoJsonStr);
}
/**
* 是规范的 GeoJson
* @param geoJson GeoJson 对象
* @return 是、否
*/
public static boolean isGeoJson(JSONObject geoJson) {
String type = geoJson.getStr("type");
boolean mark = false;
// 判断根节点
if (ArrayUtil.containsIgnoreCase(COLLECTION_TYPE, type)) {
JSONArray jsonArray = geoJson.get("features", JSONArray.class);
for (Object jsonStr : jsonArray) {
JSONObject jsonObject = JSONUtil.parseObj(jsonStr);
type = jsonObject.getStr("type");
// 判断地理要素
if (ArrayUtil.containsIgnoreCase(FEATURES_TYPE, type)) {
type = jsonObject.get("geometry", JSONObject.class).getStr("type");
// 判断几何要素
mark = ArrayUtil.containsIgnoreCase(GEO_TYPE, type);
}
if (!mark) {
return false;
}
}
}else {
// 判断地理要素
if (ArrayUtil.containsIgnoreCase(FEATURES_TYPE, type)) {
type = geoJson.get("geometry", JSONObject.class).getStr("type");
}
// 数据是几何数据
mark = ArrayUtil.containsIgnoreCase(GEO_TYPE, type);
}
return mark;
}
/**
* 不是规范的 GeoJson
* @param geoJson GeoJson 对象
* @return 是、否
*/
public static boolean isNotGeoJson(JSONObject geoJson) {
return !isGeoJson(geoJson);
}
/**
* GeoJson 转 WKT
* @param geoJson GeoJson 对象
* @return WKT 字符串
*/
public static String geoJsonToWkt(JSONObject geoJson) {
String wkt = null;
GeometryJSON gJson = new GeometryJSON();
try {
if(isGeoJson(geoJson)){
String type = geoJson.getStr("type");
// 判断是否根节点
if (ArrayUtil.containsIgnoreCase(COLLECTION_TYPE, type)) {
JSONArray geometriesArray = geoJson.get("features", JSONArray.class);
// 定义一个数组装图形对象
int size = geometriesArray.size();
Geometry[] geometries = new Geometry[size];
for (int i = 0; i < size; i++){
String str = JSONUtil.parseObj(geometriesArray.get(i)).getStr("geometry");
// 使用 GeoUtil 去读取 str
Reader reader = GeoJSONUtil.toReader(str);
Geometry geometry = gJson.read(reader);
geometries[i] = geometry;
}
GeometryCollection geometryCollection = new GeometryCollection(geometries, new GeometryFactory());
wkt = geometryCollection.toText();
}else {
String geoStr = geoJson.toString();
// 判断是否地理要素节点
if (ArrayUtil.containsIgnoreCase(FEATURES_TYPE, type)) {
geoStr = geoJson.getStr("geometry");
}
Reader reader = GeoJSONUtil.toReader(geoStr);
Geometry read = gJson.read(reader);
wkt = read.toText();
}
}
} catch (IOException e){
System.out.println("GeoJson 转 WKT 出现异常："+ e);
e.printStackTrace();
}
return wkt;
}
/**
* WKT 转 GeoJson
* @param wktStr WKT 字符串
* @return GeoJson 对象
*/
public static JSONObject wktToGeoJson(String wktStr) {
JSONObject jsonObject = new JSONObject();
try {
Geometry geometry = READER.read(wktStr);
StringWriter writer = new StringWriter();
GeometryJSON geometryJson = new GeometryJSON();
geometryJson.write(geometry, writer);
jsonObject = JSONUtil.parseObj(writer.toString());
} catch (Exception e) {
System.out.println("WKT 转 GeoJson 出现异常："+ e);
e.printStackTrace();
}
return jsonObject;
}
/**
* WKT 转 Feature
* @param wktStr WKT 字符串
* @return Feature JSON 对象
*/
public static JSONObject wktToFeature(String wktStr) {
JSONObject jsonObject = new JSONObject();
try {
SimpleFeatureType type = DataUtilities.createType("Link", "geometry:"+getGeometryType(wktStr));
SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(type);
// 按照TYPE中声明的顺序为属性赋值就可以，其他方法我暂未尝试
featureBuilder.add(READER.read(wktStr));
SimpleFeature feature = featureBuilder.buildFeature(null);
StringWriter writer = new StringWriter();
FeatureJSON fJson = new FeatureJSON();
fJson.writeFeature(feature, writer);
jsonObject = JSONUtil.parseObj(writer.toString());
}catch (Exception e) {
System.out.println("WKT 转 Feature 出现异常："+ e);
e.printStackTrace();
}
return jsonObject;
}
/**
* WKT 转 FeatureCollection
* @param wktStr WKT 字符串
* @return FeatureCollection JSON 对象
*/
public static JSONObject wktToFeatureCollection(String wktStr) {
JSONObject jsonObject = new JSONObject();
try {
String geometryType = getGeometryType(wktStr);
if (StrUtil.isNotEmpty(geometryType)) {
SimpleFeatureType type = DataUtilities.createType("Link", "geometry:" + geometryType);
SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(type);
List<SimpleFeature> features = new ArrayList<>();
SimpleFeatureCollection collection = new ListFeatureCollection(type, features);
featureBuilder.add(READER.read(wktStr));
SimpleFeature feature = featureBuilder.buildFeature(null);
features.add(feature);
StringWriter writer = new StringWriter();
FeatureJSON fJson = new FeatureJSON();
fJson.writeFeatureCollection(collection, writer);
jsonObject = JSONUtil.parseObj(writer.toString());
}
}catch (Exception e) {
System.out.println("WKT 转 FeatureCollection 出现异常："+ e);
e.printStackTrace();
}
return jsonObject;
}
}
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