RequestDTO

import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;

@Component
public class CustomFilter extends OncePerRequestFilter {

    private final ObjectMapper objectMapper;

    public CustomFilter(ObjectMapper objectMapper) {
        this.objectMapper = objectMapper;
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
            throws ServletException, IOException {

        if ("POST".equalsIgnoreCase(request.getMethod())) {
            HttpServletRequest wrappedRequest = new CachedBodyHttpServletRequest(request);
            // Read the request body and convert it to a requestDTO object
            RequestDTO requestDTO = parseRequestDTO(wrappedRequest);
            
            if (requestDTO != null) {
                // Process requestDTO as needed
                System.out.println("Received requestDTO: " + requestDTO);
            }
        }

        filterChain.doFilter(request, response);
    }

    private RequestDTO parseRequestDTO(HttpServletRequest request) throws IOException {
        // Convert request body JSON to RequestDTO object
        try (InputStream inputStream = request.getInputStream()) {
            return objectMapper.readValue(inputStream, RequestDTO.class);
        }
    }
}


import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;

public class CachedBodyHttpServletRequest extends HttpServletRequestWrapper {
    private byte[] cachedBody;

    public CachedBodyHttpServletRequest(HttpServletRequest request) throws IOException {
        super(request);
        InputStream requestInputStream = request.getInputStream();
        this.cachedBody = requestInputStream.readAllBytes();
    }

    @Override
    public ServletInputStream getInputStream() {
        return new CachedBodyServletInputStream(this.cachedBody);
    }

    @Override
    public BufferedReader getReader() {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    private static class CachedBodyServletInputStream extends ServletInputStream {
        private final ByteArrayInputStream byteArrayInputStream;

        public CachedBodyServletInputStream(byte[] cachedBody) {
            this.byteArrayInputStream = new ByteArrayInputStream(cachedBody);
        }

        @Override
        public int read() {
            return byteArrayInputStream.read();
        }

        @Override
        public boolean isFinished() {
            return byteArrayInputStream.available() == 0;
        }

        @Override
        public boolean isReady() {
            return true;
        }

        @Override
        public void setReadListener(ReadListener readListener) {
            // No implementation needed
        }
    }
}




import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;
import org.springframework.web.util.ContentCachingRequestWrapper;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
public class CustomFilter extends OncePerRequestFilter {

    private final ObjectMapper objectMapper = new ObjectMapper();

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
            throws ServletException, IOException {

        // Wrap request with ContentCachingRequestWrapper to cache the body
        ContentCachingRequestWrapper wrappedRequest = new ContentCachingRequestWrapper(request);

        filterChain.doFilter(wrappedRequest, response);

        // After filter chain, access the cached request body
        if ("POST".equalsIgnoreCase(request.getMethod())) {
            RequestDTO requestDTO = parseRequestDTO(wrappedRequest);

            if (requestDTO != null) {
                System.out.println("Received requestDTO: " + requestDTO);
            }
        }
    }

    private RequestDTO parseRequestDTO(ContentCachingRequestWrapper request) throws IOException {
        byte[] body = request.getContentAsByteArray();
        return objectMapper.readValue(body, RequestDTO.class);
    }
}