MyFilter.java
package com.ivoronline.springboot_filter_blockrequests.filters;
import java.io.IOException;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;
@Component
public class MyFilter extends OncePerRequestFilter {
@Override
public void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
throws IOException, ServletException {
//LOG
System.out.print("CHECKING REQUEST PARAMETERS: " + request.getQueryString());
//GET REQUESTS PARAMETERS
String parameterUsername = request.getParameter("username");
//CHECK REQUESTS PARAMETERS
if(parameterUsername == null) {
System.out.println(" (Parameter username missing)");
response.getWriter().println("Parameter username missing");
return;
}
System.out.println(" (Parameter username found)");
//FORWARD TO CONTROLLER
chain.doFilter(request, response);
}
}