Java – example implementation of httpservletrequestwrapper, setreadlistener / isfinished / isready?

I try to adjust an httpservletrequestwrapper (see how to read InputStream multiple times) so that the HTTP post body can be read after using the HTTP post body in the filter Now I have a challenge on how to implement servletinputstream Starting from specification 3.1, a new method must be implemented

>Finished > isready > setreadlistener

I am looking for examples or some code that can implement these methods Any tips?

Solution

Example implementation:

import com.google.common.primitives.Bytes;
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;

public class AuthenticationRequestWrapper extends HttpServletRequestWrapper {

    // tag::variables[]
    private byte[] requestBody = new byte[0];
    private boolean bufferFilled = false;
    // end::variables[]

    /**
     - Constructs a request object wrapping the given request.
     *
     - @param request The request to wrap
     - @throws IllegalArgumentException if the request is null
     */
    public AuthenticationRequestWrapper(HttpServletRequest request) {
        super(request);
    }


    // tag::getRequestBody[]
    public byte[] getRequestBody() throws IOException {
        if (bufferFilled) {
            return Arrays.copyOf(requestBody,requestBody.length);
        }

        InputStream inputStream = super.getInputStream();

        byte[] buffer = new byte[102400]; // 100kb buffer

        int bytesRead;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            requestBody = Bytes.concat(this.requestBody,Arrays.copyOfRange(buffer,bytesRead)); // <1>
        }

        bufferFilled = true;

        return requestBody;
    }
    // end::getRequestBody[]

    // tag::getInputStream[]
    @Override
    public ServletInputStream getInputStream() throws IOException {
        return new CustomServletInputStream(getRequestBody()); // <1>
    }
    // end::getInputStream[]

    private static class CustomServletInputStream extends ServletInputStream {

        private ByteArrayInputStream buffer;

        public CustomServletInputStream(byte[] contents) {
            this.buffer = new ByteArrayInputStream(contents);
        }

        @Override
        public int read() throws IOException {
            return buffer.read();
        }

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

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

        @Override
        public void setReadListener(ReadListener listener) {
            throw new RuntimeException("Not implemented");
        }
    }
}