How do I modify only part of an entity in spring data jpa?

Here is my code.

public void modifyDrawing(Long no, String name, Double lat, Double lon, String physicalName, String desc) {
   Drawing drawing = drawingRepository.findById(no)
       .orElseThrow(NoSuchElementException::new);

   drawing.setName(name);
   drawing.setLat(lat);
   drawing.setLon(lon);
   drawing.setPhysicalName(physicalName);
   drawing.setDesc(desc);
   drawingRepository.save(drawing);
}

At this time, if lat and lon are null, I want to keep the values without changing them. I am wondering how to update the entity value using only non-null parameter values.

Best regards!

CodePudding user response：

You should add an if check to make sure the latitude/longitude are not null before calling their setters.

public void modifyDrawing(Long no, String name, Double lat, Double lon, String physicalName, String desc) {
    Drawing drawing = drawingRepository.findById(no)
        .orElseThrow(NoSuchElementException::new);

    drawing.setName(name);
    if (lat != null) {
        drawing.setLat(lat);
    }
    if (lon != null) {
        drawing.setLon(lon);
    }
    drawing.setPhysicalName(physicalName);
    drawing.setDesc(desc);
    drawingRepository.save(drawing);
}

CodePudding user response：

• If you don't want to change value of lat and lon then don't set the values using drawing.setLan() and drawing.setLon().
• If you want to change value of lat and lon then use conditions in code for that. if(lon!=null) only then change the value.

i.e.

if(lon!=null){  
    drawing.setLon(lon);  
}  
if(lat != null) {  
    drawing.setLat(lon);  
}