CustomErrorController.java

package com.qprogramming.tasq.error;

import com.google.common.base.Throwables;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.text.MessageFormat;

@Controller
class CustomErrorController {

    private static final Logger LOG = LoggerFactory.getLogger(CustomErrorController.class);

    /**
     * Display an error page, as defined in web.xml <code>custom-error</code>
     * element.
     */
    @RequestMapping("generalError")
    public String generalError(HttpServletRequest request,
                               HttpServletResponse response, Model model) {
        // retrieve some useful information from the request
        Integer statusCode = (Integer) request
                .getAttribute("javax.servlet.error.status_code");
        Throwable throwable = (Throwable) request
                .getAttribute("javax.servlet.error.exception");
        String exceptionMessage = getExceptionMessage(throwable, statusCode);

        String requestUri = (String) request
                .getAttribute("javax.servlet.error.request_uri");
        if (requestUri == null) {
            requestUri = "Unknown";
        }

        String message = MessageFormat.format(
                "{0} returned for {1} with message {2}", statusCode,
                requestUri, exceptionMessage);

        model.addAttribute("errorMessage", message);
        LOG.error("General error {} for {} with message {}", statusCode, requestUri, exceptionMessage);
        return "generalError";
    }

    @RequestMapping("404")
    public String pageNotFound() {
        return "404";
    }


    private String getExceptionMessage(Throwable throwable, Integer statusCode) {
        if (throwable != null) {
            return Throwables.getRootCause(throwable).getMessage();
        }
        HttpStatus httpStatus = HttpStatus.valueOf(statusCode);
        return httpStatus.getReasonPhrase();
    }
}