geojson读写转换、生成解析（java）

一时失言乱红尘 2021-09-21 04:42 1931阅读 0赞

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# 1.Geotools中Geometry和GeoJson进行相互转换 #

## pom.xml ##

<geotools.version>17.1</geotools.version>
    
            <dependency>
                <groupId>org.geotools</groupId>
                <artifactId>gt-geojson</artifactId>
                <version>${geotools.version}</version>
            </dependency>
            
            <dependency>
                <groupId>org.geotools</groupId>
                <artifactId>gt-main</artifactId>
                <version>${geotools.version}</version>
            </dependency>
            <dependency>
                <groupId>org.geotools</groupId>
                <artifactId>gt-api</artifactId>
                <version>${geotools.version}</version>
            </dependency>
            <dependency>
                <groupId>org.geotools</groupId>
                <artifactId>gt-opengis</artifactId>
                <version>${geotools.version}</version>
            </dependency>
            <dependency>
                <groupId>org.geotools</groupId>
                <artifactId>gt-data</artifactId>
                <version>${geotools.version}</version>
            </dependency>
            <dependency>
                <groupId>org.geotools</groupId>
                <artifactId>gt-referencing</artifactId>
                <version>${geotools.version}</version>
            </dependency>

import com.fasterxml.jackson.databind.ObjectMapper;
    import com.vividsolutions.jts.geom.*;
    import com.vividsolutions.jts.geom.Point;
    import com.vividsolutions.jts.io.ParseException;
    import com.vividsolutions.jts.io.WKTReader;
    import com.vividsolutions.jts.operation.linemerge.LineMerger;
    import org.geotools.data.DataUtilities;
    import org.geotools.feature.SchemaException;
    import org.geotools.feature.simple.SimpleFeatureBuilder;
    import org.geotools.geojson.feature.FeatureJSON;
    import org.geotools.geojson.geom.GeometryJSON;
    import org.geotools.geometry.jts.JTSFactoryFinder;
    import org.opengis.feature.simple.SimpleFeature;
    import org.opengis.feature.simple.SimpleFeatureType;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Component;
    import org.springframework.util.StringUtils;
    
    import java.io.IOException;
    import java.io.StringReader;
    import java.io.StringWriter;
    import java.util.*;

## LineString–>geojson ##

// 由wkt字符串构造LineString对象
    WKTReader reader = new WKTReader( geometryFactory );
    LineString lineString = (LineString)reader.read("LINESTRING (254058.76074485347 475001.2186020431, 255351.04293761664 474966.9279243938)");
    // 设置保留6位小数，否则GeometryJSON默认保留4位小数
    GeometryJSON geometryJson = new GeometryJSON(6);
    StringWriter writer = new StringWriter();
    geometryJson.write(lineString, writer);
    System.out.println(writer.toString());
    writer.close();

## geojson–>LineString ##

LineString lineString = (LineString) geometryJson.read(new StringReader("{\n" +
                    "                \"type\": \"LineString\",\n" +
                    "                \"coordinates\": [\n" +
                    "                    [\n" +
                    "                        120.6584555,\n" +
                    "                        30.45144\n" +
                    "                    ],\n" +
                    "                    [\n" +
                    "                        120.1654515,\n" +
                    "                        30.54848\n" +
                    "                    ]\n" +
                    "                ]\n" +
                    "            }"));

Feature和FeatureCollection是geotools带属性的，其中FeatureCollection表示Geometry对象集合

## LineString转Feature ##

// geometry是必须的，其他属性可根据需求自定义，但是支持的类型有限，例如这个版本中double是不支持的，只支持float
    final SimpleFeatureType TYPE = DataUtilities.createType("Link",
                    "geometry:LineString," + // <- the geometry attribute: Point type
                            "gid:String," +   // <- a String attribute
                            "direction:Integer," +   // a number attribute
                            "orientation:Integer"
            );
    SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);
    GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();
    WKTReader reader = new WKTReader( geometryFactory );
    FeatureJSON fjson = new FeatureJSON();
    LineString lineString = (LineString)reader.read("LINESTRING (254058.76074485347 475001.2186020431, 255351.04293761664 474966.9279243938)");
    // 按照TYPE中声明的顺序为属性赋值就可以
    featureBuilder.add(lineString);
    featureBuilder.add("123456");
    featureBuilder.add(2);
    featureBuilder.add(0);
    SimpleFeature feature = featureBuilder.buildFeature(null);
    StringWriter writer = new StringWriter();
    fjson.writeFeature(feature, writer);
    System.out.println(writer.toString());

执行结果如下：

{“type”:”Feature”,”geometry”:{“type”:”LineString”,”coordinates”:[[254058.7607,475001.2186],[255351.0429,474966.9279]]},”properties”:{“gid”:”123456”,”direction”:2,”orientation”:0},”id”:”fid–5b8f258_15e04bda4b8_-8000”}

## LineString转FeatureCollection ##

String[] WKTS = { "LINESTRING (255351.04293761664 474966.9279243938, 255529.29662365236 474272.4599921228)",
                    "LINESTRING (255529.29662365236 474272.4599921228, 256166.05830998957 473979.44920198264)"};
    final SimpleFeatureType TYPE = DataUtilities.createType("Link",
                    "geometry:LineString," + // <- the geometry attribute: Point type
                            "gid:String," +   // <- a String attribute
                            "direction:Integer," +   // a number attribute
                            "orientation:Integer"
    );
    SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);
    GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();
    WKTReader reader = new WKTReader( geometryFactory );
    FeatureJSON fjson = new FeatureJSON();
    List<SimpleFeature> features = new ArrayList<>();
    SimpleFeatureCollection collection = new ListFeatureCollection(TYPE, features);
    for (String wkt : WKTS) {
        LineString lineString = (LineString)reader.read(wkt);
        featureBuilder.add(lineString);
        featureBuilder.add("123456");
        featureBuilder.add(2);
        featureBuilder.add(1);
        SimpleFeature feature = featureBuilder.buildFeature(null);
        features.add(feature);
    }
    StringWriter writer = new StringWriter();
    fjson.writeFeatureCollection(collection, writer);
    System.out.println(writer.toString());

执行结果如下：

{“type”:”FeatureCollection”,”features”:[{“type”:”Feature”,”geometry”:{“type”:”LineString”,”coordinates”:[[255351.0429,474966.9279],[255529.2966,474272.46]]},”properties”:{“gid”:”123456”,”direction”:2,”orientation”:1},”id”:”fid-67c46b85_15e0778dd81_-8000”},{“type”:”Feature”,”geometry”:{“type”:”LineString”,”coordinates”:[[255529.2966,474272.46],[256166.0583,473979.4492]]},”properties”:{“gid”:”123456”,”direction”:2,”orientation”:1},”id”:”fid-67c46b85_15e0778dd81_-7fff”}]}

如果想point和polygon和LineString都写到一个geojson文件里，geometry类型可以写成geometry，示例如下，将point和polygon放到一起

package com.test.domain.model;
    
    import java.util.Date;
    
    public class GeoModel {
    
        private String nameId;
        private String geoId;
        private String adminCode;
        private String typeId;
        private String name;
        private String nameEn;
        private String namePy;
        private String createUserId;
        private Date createAt;
        private Date updateAt;
        private String point;
        private String polygon;
        private String area;
        private String taskId;
    
    
        public String getTaskId() {
            return taskId;
        }
    
        public void setTaskId(String taskId) {
            this.taskId = taskId;
        }
    
        public String getNameId() {
            return nameId;
        }
    
        public void setNameId(String nameId) {
            this.nameId = nameId;
        }
    
        public String getGeoId() {
            return geoId;
        }
    
        public void setGeoId(String geoId) {
            this.geoId = geoId;
        }
    
        public String getAdminCode() {
            return adminCode;
        }
    
        public void setAdminCode(String adminCode) {
            this.adminCode = adminCode;
        }
    
        public String getTypeId() {
            return typeId;
        }
    
        public void setTypeId(String typeId) {
            this.typeId = typeId;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public String getNameEn() {
            return nameEn;
        }
    
        public void setNameEn(String nameEn) {
            this.nameEn = nameEn;
        }
    
        public String getNamePy() {
            return namePy;
        }
    
        public void setNamePy(String namePy) {
            this.namePy = namePy;
        }
    
        public String getCreateUserId() {
            return createUserId;
        }
    
        public void setCreateUserId(String createUserId) {
            this.createUserId = createUserId;
        }
    
        public Date getCreateAt() {
            return createAt;
        }
    
        public void setCreateAt(Date createAt) {
            this.createAt = createAt;
        }
    
        public Date getUpdateAt() {
            return updateAt;
        }
    
        public void setUpdateAt(Date updateAt) {
            this.updateAt = updateAt;
        }
    
        public String getPoint() {
            return point;
        }
    
        public void setPoint(String point) {
            this.point = point;
        }
    
        public String getPolygon() {
            return polygon;
        }
    
        public void setPolygon(String polygon) {
            this.polygon = polygon;
        }
    
        public String getArea() {
            return area;
        }
    
        public void setArea(String area) {
            this.area = area;
        }
    
    
    
    }

//将属性数据加载到list里
        List<GeoModel> geoModelList = new ArrayList<>();
            
        String writer = creatFeatureCollection(geoModelList);
    
            writer = writer.replace("{\"type\":\"Feature\"", "\n{\"type\":\"Feature\"");
    
            String path = "/data/123.geojson";
            File file = new File(path);
            try {
                FileOutputStream fos = new FileOutputStream(file);
                OutputStreamWriter osw=new OutputStreamWriter(fos, "UTF-8");
                BufferedWriter  bw=new BufferedWriter(osw);
                bw.write(writer);
                bw.close();
                osw.close();
                fos.close();
    
            } catch (FileNotFoundException e) {
                logger.error("FileNotFoundException：",e);
            
            } catch (UnsupportedEncodingException e) {
               
                logger.error("UnsupportedEncodingException：",e);
    
            } catch (IOException e) {
                
                logger.error("IOException：",e);
              
            }

public String creatFeatureCollection(List<GeoModel> geoModels){
    
            SimpleFeatureType TYPE = null;
            try {
                TYPE = DataUtilities.createType("Link",
                        "geometry:Geometry," +
                                "nameId:String," +
                                "geoId:String," +
                                "adminCode:String," +
                                "typeId:String," +
                                "name:String," +
                                "nameEn:String," +
                                "namePy:String," +
                                "createUserId:String," +
                                "createAt:Date," +
                                "updateAt:Date," +
                                "area:String," +
                                "taskId:String"
                );
            } catch (SchemaException e) {
                logger.error("SchemaException",e);
            }
    
            SimpleFeatureBuilder featureBuilderPoint = new SimpleFeatureBuilder(TYPE);
            SimpleFeatureBuilder featureBuilderPolygon = new SimpleFeatureBuilder(TYPE);
    
            WKTReader reader = new WKTReader( autowiredService.getGeometryFactory() );
            GeometryJSON gjson = new GeometryJSON(15);  // 15位小数
            FeatureJSON fjson = new FeatureJSON(gjson);
    
            List<SimpleFeature> features = new ArrayList<>();
            SimpleFeatureCollection collection = new ListFeatureCollection(TYPE, features);
    
            for (GeoModel geoModel : geoModels){
    
                Point point = null;
                try {
                    point = (Point)reader.read(geoModel.getPoint());
                } catch (ParseException e) {
                    logger.error("ParseException-point:",e);
                }
    
                featureBuilderPoint.add(point);
                featureBuilderPoint.add(geoModel.getNameId());
                featureBuilderPoint.add(geoModel.getGeoId());
                featureBuilderPoint.add(geoModel.getAdminCode());
                featureBuilderPoint.add(geoModel.getTypeId());
                featureBuilderPoint.add(geoModel.getName());
                featureBuilderPoint.add(geoModel.getNameEn());
                featureBuilderPoint.add(geoModel.getNamePy());
                featureBuilderPoint.add(geoModel.getCreateUserId());
                featureBuilderPoint.add(geoModel.getCreateAt());
                featureBuilderPoint.add(geoModel.getUpdateAt());
                featureBuilderPoint.add(geoModel.getArea());
                featureBuilderPoint.add(geoModel.getTaskId());
    
                SimpleFeature featurePoint = featureBuilderPoint.buildFeature(null);
    
                Polygon polygon = null;
                try {
                    polygon = (Polygon)reader.read(geoModel.getPolygon());
                } catch (ParseException e) {
                    logger.error("ParseException-polygon:",e);
                }
    
                featureBuilderPolygon.add(polygon);
                featureBuilderPolygon.add(geoModel.getNameId());
                featureBuilderPolygon.add(geoModel.getGeoId());
                featureBuilderPolygon.add(geoModel.getAdminCode());
                featureBuilderPolygon.add(geoModel.getTypeId());
                featureBuilderPolygon.add(geoModel.getName());
                featureBuilderPolygon.add(geoModel.getNameEn());
                featureBuilderPolygon.add(geoModel.getNamePy());
                featureBuilderPolygon.add(geoModel.getCreateUserId());
                featureBuilderPolygon.add(geoModel.getCreateAt());
                featureBuilderPolygon.add(geoModel.getUpdateAt());
                featureBuilderPolygon.add(geoModel.getArea());
                featureBuilderPolygon.add(geoModel.getTaskId());
    
                SimpleFeature featurePolygon = featureBuilderPolygon.buildFeature(null);
    
                features.add(featurePoint);
                features.add(featurePolygon);
            }
    
            StringWriter writer = new StringWriter();
    
            try {
                fjson.writeFeatureCollection(collection, writer);
            } catch (IOException e) {
                logger.error("writeFeatureCollection异常:",e);
            }
    
            return writer.toString();
    
        }