最近两周一直在看geotools，经过两周的学习对geotools有了一个大概的认识，能做做一些基本的业务分析，说到geotools就让我想到arcgis的AE，记得去年我研究AE整整用了两个月的时间才有一点认识，arcgis系列的开发体系完整而且庞大，学习成本较高，在这里主要写一篇关于shape文件的读取和创建，关于里面一些包的引用，对代码做一些简单的注解。这里我用的geotools版本是20。说个坑关于import org.locationtech.jts.geom.Geometry;和import com.vividsolutions.jts.geom.Geometry;前者是新版本所采用的JTS，后者是老版本采用的JTS，你要采用像geotools的20版本，用前者，用geotool的18版本以前的用后者，否则会报错。

一、shape文件读取

1、主要的引用

import org.geotools.data.shapefile.ShapefileDataStore;
import org.geotools.data.shapefile.ShapefileDataStoreFactory;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.data.simple.SimpleFeatureIterator;
import org.geotools.data.simple.SimpleFeatureSource;
2、获取feature代码
//shape文件路径
String shpfile = "C:/Users/lenovo/Desktop/shape/locations1.shp";
File file = new File(shpfile);
//声明一个存储空间
ShapefileDataStore shpDataStore = null;
//将文件读取到存储空间
shpDataStore = new ShapefileDataStore(file.toURL());
//设置编码，防止中文乱码
Charset charset = Charset.forName("GBK");
shpDataStore.setCharset(charset);
//获取图层名称
String typeName = shpDataStore.getTypeNames()[0];
System.out.println(typeName);
SimpleFeatureSource featureSource = null;
//根据图层名称来获取要素的source
featureSource = shpDataStore.getFeatureSource (typeName);
//获取要素集
SimpleFeatureCollection result = featureSource.getFeatures();
//获取要素集合，方便进行迭代读取每一个要素
SimpleFeatureIterator itertor = result.features();
3、关于要素集合迭代代码示例
//循环读取feature，itertor.hasNext()表示游标下一个是否有数据，有返回ture,否则为false
while (itertor.hasNext())
{
//获取每一个要素
SimpleFeature feature = itertor.next();
}

二、创建shape文件

1、主要的引用

import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.AttributeDescriptor;
import org.geotools.data.FeatureWriter;
import org.geotools.data.Transaction;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.Point;
2、创建shape文件核心代码
//设置要素的字段名称及其类型
final SimpleFeatureType TYPE =
DataUtilities.createType(
"Location",
"the_geom:Point:srid=4326,"// geometry属性设置
+ "name:String,"// 一个字符串属性
+ "number:Integer" // 数字属性设置
);
//创建要素集合
List features = new ArrayList<>();
//创建要素模板
SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);
double latitude = Double.parseDouble(tokens[0]);
double longitude = Double.parseDouble(tokens[1]);
String name = tokens[2].trim();
int number = Integer.parseInt(tokens[3].trim());
//创建一个点geometry
Point point = geometryFactory.createPoint(new Coordinate(longitude, latitude));
//添加geometry属性
featureBuilder.add(point);
/添加name属性
featureBuilder.add(name);
//添加number属性
featureBuilder.add(number);
//构建要素
SimpleFeature feature = featureBuilder.buildFeature(null);
//将要素添加到要素几何中
features.add(feature);
String shpfile = "C:/Users/lenovo/Desktop/shape/New.shp";
File newFile = getNewShapeFile(file);
//创建shapefileDataStore工厂
ShapefileDataStoreFactory dataStoreFactory = new ShapefileDataStoreFactory();
//参数设置
Map params = new HashMap<>();
params.put("url", newFile.toURI().toURL());
params.put("create spatial index", Boolean.TRUE);
//根据关键字创建shapefileDataStore
ShapefileDataStore newDataStore =(ShapefileDataStore) dataStoreFactory.createNewDataStore(params);
//设置编码，防止中文乱码
Charset charset = Charset.forName("GBK");
newDataStore.setCharset(charset);
//创建文件描述内容
newDataStore.createSchema(TYPE);
//设置Writer，并设置为自动提交
FeatureWriter writer = ds.getFeatureWriter(ds.getTypeNames()[0], Transaction.AUTO_COMMIT);
//循环写入要素
while (itertor.hasNext())
{
//获取要写入的要素
SimpleFeature feature = itertor.next();
//将要写入位置
SimpleFeature featureBuf = writer.next();
//设置写入要素所有属性
featureBuf.setAttributes(feature.getAttributes());
//获取the_geom属性的值
Geometry geo =(Geometry) feature.getAttribute("the_geom");
Geometry geoBuffer = geoR.calBuffer(geo, 3);
System.out.println(geoBuffer);
//重新覆盖the_geom属性的值，这里的geoBuffer必须为Geometry类型
featureBuf.setAttribute("the_geom", geoBuffer);
}
//将所有数据写入
writer.write();
//关闭写入流
writer.close();