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);

    }