记录一下如何创建创建缓冲区并获取缓冲区内的要素，便于以后查找使用

 static SimpleFeatureSource featureSource = null;  
 static CoordinateReferenceSystem targetCRS;  

　　　static String geometryPropertyName;
static FilterFactory2 ff;
public SimpleFeatureCollection grabFeaturesInBoundingBox(double x1, double y1, double x2, double y2)
throws Exception {
ShapefileDataStoreFactory dataStoreFactory = new ShapefileDataStoreFactory();
ShapefileDataStore sds = (ShapefileDataStore)dataStoreFactory.createDataStore
(new File("E://Merge_direction.shp").toURI().toURL());

    Charset charset = Charset.forName("GBK");  
    sds.setCharset(charset);  
    String typeName = sds.getTypeNames()\[0\];  
    featureSource =  sds.getFeatureSource (typeName);  
    FilterFactory2 ff = CommonFactoryFinder.getFilterFactory2();  
    FeatureType schema = featureSource.getSchema();

    geometryPropertyName = schema.getGeometryDescriptor().getLocalName();  
    targetCRS = schema.getGeometryDescriptor().getCoordinateReferenceSystem();

    ReferencedEnvelope bbox = new ReferencedEnvelope(x1, y1, x2, y2, targetCRS);

    Filter filter = ff.bbox(ff.property(geometryPropertyName), bbox);  
    return featureSource.getFeatures(filter);  
}