Drawing arrow on line using SLD of GeoServer?

I have a line layer in geoserver as in the 1st image.

How can I draw an arrow on the line like in the 2nd image?

The line.rar includes a shapefile and a sld file.

Can edit a sample for me?

line.rar(download)

Answer

The GeoServer documentations states how to extract start and end points with geometry transformations (just use the end- point rule). The code example provided uses square as marks, but you could always replace this with e.g. the shape symbol shape://oarrow.

EDIT: I forgot to mention how to rotate the triangle correctly (couldn't find it in the documentation, but took it from page 38 in this presentation)!

the_geom

EDIT2: Just wanted to make sure everything works as described, here is a code sample based on GeoServer's default blue line SLD style:

        xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd" 
        xmlns="http://www.opengis.net/sld" 
        xmlns:ogc="http://www.opengis.net/ogc" 
        xmlns:xlink="http://www.w3.org/1999/xlink" 
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    
        Blue arrows
        

            
            
                
                    Blue_Arrow_Line
                    
                        
                            #0000FF
                            2
                        
                    

                    
                        
                            
                                the_geom
                            
                        
                        
                            
                                shape://oarrow
                                

                                #0000FF
                                0.5
                                
                                
                                    #0000FF
                                    2
                                
                            
                            30
                            

                                
                                    the_geom
                                
                            
                        
                    
                
            
        
    

This is how it should look like: