- To add custom response headers in a Spring boot application use ResponeEntity class.
- Set the values using HttpHeader object.
- Set the header object in response entity
- Set the values using HttpHeader object.

- To set a response header for all the response , implement a Filter class and set the header in the ServletResponse class
- Code Snippet
@Component
public class ResFilter implements Filter {
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
HttpServletResponse httpServletResponse = (HttpServletResponse) servletResponse;
httpServletResponse.setHeader("header name", "header value");
filterChain.doFilter(servletRequest, servletResponse);
}
- Output of the above 2 code snippets

Thank You !!