GeoTools——shp转geojson
倪阳飇
目录
一、引言
数据库中经常存储的格式是符合OGC标准的WKT或WKB，而在网络中经常传输的格式是json，因此我们会经常把各种数据转为geojson的形式以服务形式发出，供客户端使用。当然你硬要用wkt格式也行，没人管你，自己知道就ok，由于涉及到属性数据只是建议geojson比较方便，毕竟WFS也是用的geojson返回的==
二、代码操作
1、服务端
读取shp数据，解析出simplefeature，使用featurejson转化为json，然后拼接输出。
/**
* 后台将shp数据转为geojson，返回
* @return
*/
@RequestMapping("/geojson")
@ResponseBody
public Object shp2geojson()
{
String shpPath=this.getClass().getResource("/").getFile()+"/file/pointgbk.shp";
String jsonPath=this.getClass().getResource("/").getFile()+"file/point.geojson";
Map map = new HashMap();
//新建json对象
FeatureJSON fjson = new FeatureJSON();
JSONObject geojsonObject=new JSONObject();
geojsonObject.put("type","FeatureCollection");
try{
//获取featurecollection
File file = new File(shpPath);
ShapefileDataStore shpDataStore = null;
shpDataStore = new ShapefileDataStore(file.toURL());
//设置编码
/* Charset charset = Charset.forName("GBK");
shpDataStore.setCharset(charset);*/
String typeName = shpDataStore.getTypeNames()[0];
SimpleFeatureSource featureSource = null;
featureSource = shpDataStore.getFeatureSource (typeName);
SimpleFeatureCollection result = featureSource.getFeatures();
SimpleFeatureIterator itertor = result.features();
JSONArray array = new JSONArray();
//遍历feature转为json对象
while (itertor.hasNext())
{
SimpleFeature feature = itertor.next();
StringWriter writer = new StringWriter();
fjson.writeFeature(feature, writer);
String temp=writer.toString();
byte[] b=temp.getBytes("iso8859-1");
temp=new String(b,"gbk");
System.out.println(temp);
JSONObject json = JSON.parseObject(temp);
array.add(json);
}
geojsonObject.put("features",array);
itertor.close();
long startTime=System.currentTimeMillis();
//将json字符串使用字符流写入文件
/* File outputfile=new File(jsonPath);
BufferedWriter bufferedWriter=new BufferedWriter(new FileWriter(outputfile));
bufferedWriter.write(JSON.toJSONString(geojsonObject));
bufferedWriter.flush();
bufferedWriter.close();*/
File outputfile=new File(jsonPath);
FileOutputStream fileOutputStream=new FileOutputStream(outputfile);
OutputStreamWriter outputStreamWriter=new OutputStreamWriter(fileOutputStream,"utf-8");
outputStreamWriter.write(JSON.toJSONString(geojsonObject));
outputStreamWriter.flush();
outputStreamWriter.close();
//将json字符串使用字节流写入文件
/* File outputfile=new File(jsonPath);
BufferedOutputStream bufferedOutputStream=new BufferedOutputStream(new FileOutputStream(outputfile));
byte[] bytes= JSON.toJSONString(geojsonObject).getBytes("utf-8");
bufferedOutputStream.write(bytes);
//fileOutputStream.write(JSON.toJSONString(geojsonObject));
bufferedOutputStream.flush();
bufferedOutputStream.close();*/
long endTime=System.currentTimeMillis();
System.out.println("当前程序耗时："+(endTime-startTime)+"ms");
}
catch(Exception e){
map.put("status", "failure");
map.put("message", e.getMessage());
e.printStackTrace();
}
return geojsonObject;
}
2、返回数据
{"features":[{"geometry":{"coordinates":[508909.854,299887.23],"type":"Point"},"id":"pointgbk.2","type":"Feature","properties":{"ExtendedEn":"{ 83103 } { L31-20201081-24 L31-20201081-24 }","SubClasses":"AcDbEntity:AcDbText:AcDbText","EntityHand":"1522","Text":"37.24","Linetype":"","Layer":"文字层组-标注"}},{"geometry":{"coordinates":[508884.9711,299895.6874],"type":"Point"},"id":"pointgbk.3","type":"Feature","properties":{"ExtendedEn":"{ 83103 } { L31-20201081-25 L31-20201081-25 }","SubClasses":"AcDbEntity:AcDbText:AcDbText","EntityHand":"1523","Text":"37.23","Linetype":"","Layer":"文字层组-标注"}},……],"type":"FeatureCollection"}
三、总结
- 使用wkt与geojson；
- 代码操作将shp中的feature转化为geojson；
补充：
geojson转shp
Map map = new HashMap();
GeometryJSON gjson = new GeometryJSON();
try{
String strJson = cm.getFileContent(jsonPath);
JSONObject json = new JSONObject(strJson);
JSONArray features = (JSONArray) json.get("features");
JSONObject feature0 = new JSONObject(features.get(0).toString());
System.out.println(feature0.toString());
String strType = ((JSONObject)feature0.get("geometry")).getString("type").toString();
Class<?> geoType = null;
switch(strType){
case "Point":
geoType = Point.class;
case "MultiPoint":
geoType = MultiPoint.class;
case "LineString":
geoType = LineString.class;
case "MultiLineString":
geoType = MultiLineString.class;
case "Polygon":
geoType = Polygon.class;
case "MultiPolygon":
geoType = MultiPolygon.class;
}
//创建shape文件对象
File file = new File(shpPath);
Map<String, Serializable> params = new HashMap<String, Serializable>();
params.put( ShapefileDataStoreFactory.URLP.key, file.toURI().toURL() );
ShapefileDataStore ds = (ShapefileDataStore) new ShapefileDataStoreFactory().createNewDataStore(params);
//定义图形信息和属性信息
SimpleFeatureTypeBuilder tb = new SimpleFeatureTypeBuilder();
tb.setCRS(DefaultGeographicCRS.WGS84);
tb.setName("shapefile");
tb.add("the_geom", geoType);
tb.add("POIID", Long.class);
ds.createSchema(tb.buildFeatureType());
//设置编码
Charset charset = Charset.forName("GBK");
ds.setCharset(charset);
//设置Writer
FeatureWriter<SimpleFeatureType, SimpleFeature> writer = ds.getFeatureWriter(ds.getTypeNames()[0], Transaction.AUTO_COMMIT);
for(int i=0,len=features.length();i<len;i++){
String strFeature = features.get(i).toString();
Reader reader = new StringReader(strFeature);
SimpleFeature feature = writer.next();
feature.setAttribute("the_geom",gjson.readMultiPolygon(reader));
feature.setAttribute("POIID",i);
writer.write();
}
writer.close();
ds.dispose();
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