How to inject ResourceInfo in javax.servlet.Filter

问题

I am trying to register time metrics based on the service method but not able to inject ResourceInfo.

I want to write some generic logic to register the time based on the service.

Here is my code:

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.ws.rs.container.ResourceInfo;

@WebFilter("/*")
public class MetricsGeneraterFilter implements Filter {

    @Context
    private ResourceInfo resourceInfo;

    @Override
    public void destroy() {
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        long startTime = System.currentTimeMillis();
        chain.doFilter(request, response);
        long elapsedTime = System.currentTimeMillis() - startTime;
        System.out.println(resourceInfo.getResourceMethod().getName() + "--->" + elapsedTime);
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

}

How to inject ResourceInfo in javax.servlet.Filter?

回答1:

I've used ContainerRequestFilter and ContainerResponseFilter to solve for this problem.

ContainerRequestFilter:

@Provider
public class RequestContextLoggingFilter implements ContainerRequestFilter{

    public static final String REQUEST_START_TIME = "REQUEST_START_TIME";

    @Override
    public void filter(ContainerRequestContext requestContext) throws IOException {

        requestContext.setProperty(REQUEST_START_TIME, Instant.now());
    }
}

ContainerResponseFilter:

@Provider
@Priority(Priorities.USER)
public class ResponseLogFilter implements ContainerResponseFilter{

private Logger logger = LoggerFactory.getLogger(ResponseLogFilter.class);

@Override
  public void filter(ContainerRequestContext requestContext, ContainerResponseContext responseContext) throws IOException {

      try {
          Instant end = Instant.now();
          Instant start = (Instant) requestContext.getProperty(RequestContextLoggingFilter.REQUEST_START_TIME);
          logger.info("Done executing request with request_execution_time={} ms",
                Duration.between(start, end).toMillis());
      }catch (Exception e){
          logger.warn("error logging response time", e);
      }

  }
}

You can also use Jersey's Monitoring and Diagnostics module: https://jersey.github.io/documentation/latest/monitoring_tracing.html.

I haven't used it in production applications as it is in beta as of release >2.1

回答2:

Try using a JAX-RS Filter instead. These operate just like Servlet filters but better as they are within the bounds of JAX-RS and can do many things that a Servlet Filters can't.

In order to do so, just make that class implement ContainerResponseFilter and ContainerRequestContext, and add it to your JAX-RS application (I.e. add the @Provider annotation or add it to your web.xml). Then implement the two methods. You can store the startTime in the RequestContext object's parameters.

I will edit this with a link to my own filter that does exactly this when I get a chance.

来源：https://stackoverflow.com/questions/49225987/how-to-inject-resourceinfo-in-javax-servlet-filter

标签

rest

jersey

jax-rs

cxf

jersey-2.0