org.springframework.boot.autoconfigure.web.BasicErrorController.java Source code

Java tutorial

Introduction

Here is the source code for org.springframework.boot.autoconfigure.web.BasicErrorController.java

Source

/*
 * Copyright 2012-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot.autoconfigure.web;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Date;
import java.util.LinkedHashMap;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.embedded.AbstractEmbeddedServletContainerFactory;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindException;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver;

/**
 * Basic global error {@link Controller}, rendering servlet container error codes and
 * messages where available. More specific errors can be handled either using Spring MVC
 * abstractions (e.g. {@code @ExceptionHandler}) or by adding servlet
 * {@link AbstractEmbeddedServletContainerFactory#setErrorPages(java.util.Set) container
 * error pages}.
 * 
 * @author Dave Syer
 */
@Controller
@ControllerAdvice
@Order(0)
public class BasicErrorController implements ErrorController {

    private static final String ERROR_KEY = "error";

    private final Log logger = LogFactory.getLog(BasicErrorController.class);

    private DefaultHandlerExceptionResolver resolver = new DefaultHandlerExceptionResolver();

    @Value("${error.path:/error}")
    private String errorPath;

    @Override
    public String getErrorPath() {
        return this.errorPath;
    }

    @ExceptionHandler(Exception.class)
    public void handle(HttpServletRequest request, HttpServletResponse response, Exception e) throws Exception {
        this.resolver.resolveException(request, response, null, e);
        if (response.getStatus() == HttpServletResponse.SC_OK) {
            response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        }
        // There's only one exception so it's easier for the error controller to identify
        // it this way...
        request.setAttribute(ErrorController.class.getName(), e);
        if (e instanceof BindException) {
            // ... but other error pages might be looking for it here as well
            request.setAttribute(BindingResult.MODEL_KEY_PREFIX + ((BindException) e).getObjectName(), e);
        }
    }

    @RequestMapping(value = "${error.path:/error}", produces = "text/html")
    public ModelAndView errorHtml(HttpServletRequest request) {
        Map<String, Object> map = extract(new ServletRequestAttributes(request), false, false);
        return new ModelAndView(ERROR_KEY, map);
    }

    @RequestMapping(value = "${error.path:/error}")
    @ResponseBody
    public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
        ServletRequestAttributes attributes = new ServletRequestAttributes(request);
        String trace = request.getParameter("trace");
        Map<String, Object> extracted = extract(attributes, trace != null && !"false".equals(trace.toLowerCase()),
                true);
        HttpStatus statusCode = getStatus((Integer) extracted.get("status"));
        return new ResponseEntity<Map<String, Object>>(extracted, statusCode);
    }

    private HttpStatus getStatus(Integer value) {
        try {
            return HttpStatus.valueOf(value);
        } catch (Exception ex) {
            return HttpStatus.INTERNAL_SERVER_ERROR;
        }
    }

    @Override
    public Map<String, Object> extract(RequestAttributes attributes, boolean trace, boolean log) {
        Map<String, Object> map = new LinkedHashMap<String, Object>();
        map.put("timestamp", new Date());
        try {
            Throwable error = (Throwable) attributes.getAttribute(ErrorController.class.getName(),
                    RequestAttributes.SCOPE_REQUEST);
            Object obj = attributes.getAttribute("javax.servlet.error.status_code",
                    RequestAttributes.SCOPE_REQUEST);
            int status = 999;
            if (obj != null) {
                status = (Integer) obj;
                map.put(ERROR_KEY, HttpStatus.valueOf(status).getReasonPhrase());
            } else {
                map.put(ERROR_KEY, "None");
            }
            map.put("status", status);
            if (error == null) {
                error = (Throwable) attributes.getAttribute("javax.servlet.error.exception",
                        RequestAttributes.SCOPE_REQUEST);
            }
            if (error != null) {
                while (error instanceof ServletException && error.getCause() != null) {
                    error = ((ServletException) error).getCause();
                }
                map.put("exception", error.getClass().getName());
                addMessage(map, error);
                if (trace) {
                    StringWriter stackTrace = new StringWriter();
                    error.printStackTrace(new PrintWriter(stackTrace));
                    stackTrace.flush();
                    map.put("trace", stackTrace.toString());
                }
                if (log) {
                    this.logger.error(error);
                }
            } else {
                Object message = attributes.getAttribute("javax.servlet.error.message",
                        RequestAttributes.SCOPE_REQUEST);
                map.put("message", message == null ? "No message available" : message);
            }
            String path = (String) attributes.getAttribute("javax.servlet.error.request_uri",
                    RequestAttributes.SCOPE_REQUEST);
            map.put("path", path == null ? "No path available" : path);
            return map;
        } catch (Exception ex) {
            map.put(ERROR_KEY, ex.getClass().getName());
            map.put("message", ex.getMessage());
            if (log) {
                this.logger.error(ex);
            }
            return map;
        }
    }

    protected void addMessage(Map<String, Object> map, Throwable error) {
        if (error instanceof BindingResult) {
            BindingResult result = (BindingResult) error;
            if (result.getErrorCount() > 0) {
                map.put("errors", result.getAllErrors());
                map.put("message", "Validation failed for object='" + result.getObjectName() + "'. Error count: "
                        + result.getErrorCount());
            } else {
                map.put("message", "No errors");
            }
        } else {
            map.put("message", error.getMessage());
        }
    }

}