一、场景
数据库中某一张表存放了一些MultiPolygon数据，需要提供接口，根据这些数据生成对应的（.shp）文件，再压缩放在下载链接中导出。
二、思路
1.查询出这些数据
2.将数据封装成一个JSONArray
3.在固定路径创建一个shp文件
4.将the_geom数据封装为Geometry对象
5.将Geometry对象封装成Polygon[]数组
6.使用GeometryFactory().createMultiPolygon创建Geometry对象
7.将数据写入文件
8.将文件添加到压缩包输出
三、代码实现
生成压缩文件的工具类如下：
package ktw.micro.service.topicrepo.center.util;
/**
* @ClassName: ShapeHelper
* @Description:
* @author: zhang zihao
* @date: 2022/5/10 11:51
*/
import com.alibaba.fastjson.JSON;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.io.WKTReader;
import ktw.micro.service.gisutil.GeometryUtil;
import ktw.micro.service.gisutil.serializer.WKTToByteArrayDeserializer;
import org.geotools.data.FeatureWriter;
import org.geotools.data.Transaction;
import org.geotools.data.shapefile.ShapefileDataStore;
import org.geotools.data.shapefile.ShapefileDataStoreFactory;
import org.geotools.feature.simple.SimpleFeatureTypeBuilder;
import org.geotools.geometry.jts.JTSFactoryFinder;
import org.geotools.referencing.crs.DefaultGeographicCRS;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import java.io.*;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class ShapeHelper {
public ShapeHelper(){
super();
}
public void write2ShapeFile(String shpPath, String[] header, List data){
try{
//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", MultiPolygon.class);
for(int i= 0;i<header.length;i++){
String field = header[i];
tb.add(field.toUpperCase(), String.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);
//写入文件信息
List geometries=new ArrayList();
for (Object object:data) {
Geometry geometry = GeometryUtil.wktToGeometry(JSON.toJSONString(object));
geometries.add(geometry);
}
for(int i=0;i<data.size();i++){
SimpleFeature feature = writer.next();
Map<String, Object> row = (Map)data.get(i);
WKTReader reader = new WKTReader();
Geometry geometry = reader.read(row.get("the_geom").toString());
int geoUnm = geometry.getNumGeometries(); // 一个geometry可能含有n个geometry
Polygon[] polygons = new Polygon[geoUnm];
for (int j = 0; j < geoUnm; j++) {
Polygon singleGeo =(Polygon) geometry.getGeometryN(j); //获取其中每一个geometry
int numGeometries = singleGeo.getNumGeometries();
LinearRing exteriorRing = (LinearRing)singleGeo.getExteriorRing();
int numInteriorRing = singleGeo.getNumInteriorRing();
LinearRing holes[] = new LinearRing[numInteriorRing];
for (int k = 0; k < numInteriorRing; k++) {
LinearRing interiorRing = (LinearRing)singleGeo.getInteriorRingN(k);
holes[k] = interiorRing;
}
Polygon Polygon1 = new GeometryFactory().createPolygon(exteriorRing, holes);
Polygon1.setSRID(4490);
//Coordinate[] coords = singleGeo.getCoordinates();
polygons[j] = Polygon1;
}
Geometry geom = new GeometryFactory().createMultiPolygon(polygons);
feature.setAttribute("the_geom", geom);
for (Map.Entry entry : row.entrySet()) {
feature.setAttribute(entry.getKey().toString().toUpperCase()
, entry.getValue());
}
}
writer.write();
writer.close();
ds.dispose();
//添加到压缩文件
zipShapeFile(shpPath);
}catch (Exception e){
e.printStackTrace();
}
}
//生成压缩包
public void zipShapeFile(String shpPath){
try{
File shpFile = new File(shpPath);
String shpRoot = shpFile.getParentFile().getPath(),
_shpName = shpFile.getName(),
shpName = _shpName.substring(0, _shpName.lastIndexOf("."));
String zipPath = shpRoot+File.separator+shpName+".zip";
File zipFile = new File(zipPath);
InputStream input = null;
ZipOutputStream zipOut = new ZipOutputStream(new FileOutputStream(zipFile));
// zip的名称为
zipOut.setComment(shpName);
String[] shpFiles = new String[]{
shpRoot+File.separator+shpName+".dbf",
shpRoot+File.separator+shpName+".prj",
shpRoot+File.separator+shpName+".shp",
shpRoot+File.separator+shpName+".shx",
};
for(int i=0;i<shpFiles.length;i++){
File _file = new File(shpFiles[i]);
input = new FileInputStream(_file);
zipOut.putNextEntry(new ZipEntry(_file.getName()));
int temp = 0;
while ((temp = input.read()) != -1) {
zipOut.write(temp);
}
input.close();
}
zipOut.close();
}catch (Exception e){
e.printStackTrace();
}
}
}
Service层逻辑实现如下：
public void exportSpatialService(HttpServletResponse response,String dbid, String tablename) throws Exception {
//设置请求头
response.setContentType("application/x-msdownload");
response.setHeader("Content-Disposition",
"attachment; filename=" + URLEncoder.encode((tablename) + ".zip",
"UTF-8"));
response.setCharacterEncoding("UTF-8");
//首先从数据库中查出数据
DatabaseEntity databaseEntity = databaseService.getById(dbid);
ISQLHelper isqlHelper = SQLHelper.get(databaseEntity.convertTo());
String sql = "SELECT * FROM \"public\".\"" + tablename.toUpperCase() + "\"";
JSONArray objects = isqlHelper.queryBySql(sql);
//创建固定路径
String tmpDir = System.getProperty("java.io.tmpdir");
String tmpFile = tmpDir + tablename+".shp";
//调用ShapeHelper创建包含shape文件的压缩包
HashMap hashMap = JSONObject.parseObject(JSONObject.toJSONString(objects.get(0)),HashMap.class);
String[] str = (String[])hashMap.keySet().toArray(new String[hashMap.keySet().size()]);
new ShapeHelper().write2ShapeFile(tmpFile,str,objects);
//输出文件
File file=new File(tmpDir + tablename+".zip");
//通过文件路径得到一个输入流
String path = file.getPath();
FileInputStream fis = new FileInputStream(path);
//创建字节输出流,这里我们使用Servlet的输出流
ServletOutputStream sos = response.getOutputStream();
//执行输出操作
int len = 1;
byte[] b = new byte[1024]; //创建一个字节数组
while( (len = fis.read(b)) != -1) {
sos.write(b, 0, len);
}
sos.close();
fis.close();
//删除本地文件
List<String> filelist=new ArrayList<>();
filelist.add(".zip");
filelist.add(".shp");
filelist.add(".dbf");
filelist.add(".prj");
filelist.add(".shx");
filelist.add(".fix");
for (String s:filelist) {
FileUtil.delete(tmpDir + tablename+s);
}
}
Controller层调用如下：
/**
* @param dbid,tablename
* @description 根据数据源id和数据表名称导出数据
* @return
* @author zhang zihao
* @date 2022/5/5
**/
@GetMapping("/exportdata/{dbid}/{tablename}")
public void exportData(@PathVariable String dbid, @PathVariable String tablename) throws Exception {
//首先判断当前表是空间数据表还是业务数据表
DatabaseEntity databaseEntity = databaseService.getById(dbid);
ISQLHelper isqlHelper = SQLHelper.get(databaseEntity.convertTo());
String databaseSql = "select count(*) from information_schema.columns where table_name = '" + tablename.toUpperCase() + "' and column_name = 'the_geom'";
JSONArray execute = isqlHelper.queryBySql(databaseSql);
String count = execute.getJSONObject(0).getString("count");
if (count.equals("1")) {
//空间数据
RequestAttributes ra = RequestContextHolder.currentRequestAttributes();
repoInfoService.exportSpatialService(((ServletRequestAttributes) ra).getResponse(),dbid, tablename);
} else {
//业务数据
structureService.exportBusinessData(tablename, dbid);
}
}
四、相关数据格式
1.数据库查询出来的格式
2.调用工具类三个参数的格式
3.执行完工具类方法之后，会在固定路径生成五个空间文件以及对应的压缩包，接下来只需要将这个压缩包放在HttpServletResponse中输出即可，最后将生成在固定路径的文件删除。
