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前言：ErrorController是SpringBoot调用Controller出错时的一个统一处理接口，它的实现为BasicErrorController。

一、背景

使用SpringBoot调用controller时，如果系统出现404,405,500等这种报错信息时，系统默认会展示如下信息：
如果把这种错误展示给用户看，对于用户来说是不友好的。对于这种报错信息，我们需要做统一处理，我们根据不同的错误类型，返回给用户不同的返回信息。SpringBoot就提供了一个这样统一处理异常的接口类ErrorController。下面我们简单说明一下如何实现一个自定义的异常处理机制。

二、SpringBoot的默认异常处理BasicErrorController

在看了源码之后发现有一个配置类ErrorMvcAutoConfiguration，当工程启动的时候，已经把BasicErrorController加载到Spring容器里面。因此当我们程序报错的时候会直接调用这个处理异常的controller。

错误地址配置：

看完源码，我们发现如果你在配置文件配置了server.error.path的话，就会使用你配置的异常处理地址，如果没有就会使用你配置的error.path路径地址，如果还是没有，默认使用/error来作为发生异常的处理地址。

BasicErrorController这两个方法是关键

• getErrorPath()错误页路径
• errorHtml()返回错误页信息

 public String getErrorPath() {
        return this.errorProperties.getPath();
    }

    @RequestMapping(
        produces = {"text/html"}
    )
    public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) {
        HttpStatus status = this.getStatus(request);
        Map<String, Object> model = Collections.unmodifiableMap(this.getErrorAttributes(request, this.isIncludeStackTrace(request, MediaType.TEXT_HTML)));
        response.setStatus(status.value());
        ModelAndView modelAndView = this.resolveErrorView(request, response, status, model);
        return modelAndView != null ? modelAndView : new ModelAndView("error", model);
    }

三、自定义错误异常

通过研究BasicErrorController，我们自定义错误异常需要实现ErrorContrroller大概需要四点。

• 实现ErrorController接口，并重写getErrorPath()方法，指定异常跳转的url；
• 对类添加@RestController注解，添加异常跳转url的Controller；
• 获取请求响应的类型，针对不同的响应错误类型，做不同的逻辑处理。
• 在template目录下存放错误页面的HTML文件。

@Slf4j
@Controller
@RequestMapping("/error")
@EnableConfigurationProperties({ServerProperties.class})
public class ErrorPagesController implements ErrorController {

    private ErrorAttributes errorAttributes;

    @Autowired
    private ServerProperties serverProperties;

    /**
     * 初始化ExceptionController
     *
     * @param errorAttributes
     */
    @Autowired
    public ErrorPagesController(ErrorAttributes errorAttributes) {
        Assert.notNull(errorAttributes, "ErrorAttributes must not be null");
        this.errorAttributes = errorAttributes;
    }

    @RequestMapping("/404")
    public ModelAndView errorHtml404(HttpServletRequest request, HttpServletResponse response, WebRequest webRequest) {
        response.setStatus(HttpStatus.NOT_FOUND.value());
        Map<String, Object> model = getErrorAttributes(webRequest, isIncludeStackTrace(request, MediaType.TEXT_HTML));
        model.put("queryString", request.getQueryString());

        return new ModelAndView("error/404", model);
    }

    @RequestMapping("/403")
    public ModelAndView errorHtml403(HttpServletRequest request, HttpServletResponse response, WebRequest webRequest) {
        response.setStatus(HttpStatus.FORBIDDEN.value());
        // 404拦截规则，如果是静态文件发生的404则不记录到DB
        Map<String, Object> model = getErrorAttributes(webRequest, isIncludeStackTrace(request, MediaType.TEXT_HTML));
        model.put("queryString", request.getQueryString());
        if (!String.valueOf(model.get("path")).contains(".")) {
            model.put("status", HttpStatus.FORBIDDEN.value());
        }
        return new ModelAndView("error/403", model);
    }

    @RequestMapping("/400")
    public ModelAndView errorHtml400(HttpServletRequest request, HttpServletResponse response, WebRequest webRequest) {
        response.setStatus(HttpStatus.BAD_REQUEST.value());
        Map<String, Object> model = getErrorAttributes(webRequest, isIncludeStackTrace(request, MediaType.TEXT_HTML));
        model.put("queryString", request.getQueryString());
        return new ModelAndView("error/400", model);
    }

    @RequestMapping("/401")
    public ModelAndView errorHtml401(HttpServletRequest request, HttpServletResponse response, WebRequest webRequest) {
        response.setStatus(HttpStatus.UNAUTHORIZED.value());
        Map<String, Object> model = getErrorAttributes(webRequest, isIncludeStackTrace(request, MediaType.TEXT_HTML));
        model.put("queryString", request.getQueryString());
        return new ModelAndView("error/401", model);
    }

    @RequestMapping("/500")
    public ModelAndView errorHtml500(HttpServletRequest request, HttpServletResponse response, WebRequest webRequest) {
        response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR.value());
        Map<String, Object> model = getErrorAttributes(webRequest, isIncludeStackTrace(request, MediaType.TEXT_HTML));
        model.put("queryString", request.getQueryString());
        return new ModelAndView("error/500", model);
    }

    /**
     * Determine if the stacktrace attribute should be included.
     *
     * @param request
     *         the source request
     * @param produces
     *         the media type produced (or {@code MediaType.ALL})
     * @return if the stacktrace attribute should be included
     */
    protected boolean isIncludeStackTrace(HttpServletRequest request,
                                          MediaType produces) {
        ErrorProperties.IncludeStacktrace include = this.serverProperties.getError().getIncludeStacktrace();
        if (include == ErrorProperties.IncludeStacktrace.ALWAYS) {
            return true;
        }
        return include == ErrorProperties.IncludeStacktrace.ON_TRACE_PARAM && getTraceParameter(request);
    }


    /**
     * 获取错误的信息
     *
     * @param webRequest
     * @param includeStackTrace
     * @return
     */
    private Map<String, Object> getErrorAttributes(WebRequest webRequest,
                                                   boolean includeStackTrace) {
        return this.errorAttributes.getErrorAttributes(webRequest, includeStackTrace);
    }

    /**
     * 是否包含trace
     *
     * @param request
     * @return
     */
    private boolean getTraceParameter(HttpServletRequest request) {
        String parameter = request.getParameter("trace");
        return parameter != null && !"false".equalsIgnoreCase(parameter);
    }

    /**
     * 获取错误编码
     *
     * @param request
     * @return
     */
    private HttpStatus getStatus(HttpServletRequest request) {
        Integer statusCode = (Integer) request
                .getAttribute("javax.servlet.error.status_code");
        if (statusCode == null) {
            return HttpStatus.INTERNAL_SERVER_ERROR;
        }
        try {
            return HttpStatus.valueOf(statusCode);
        } catch (Exception ex) {
            log.error("获取当前HttpStatus发生异常", ex);
            return HttpStatus.INTERNAL_SERVER_ERROR;
        }
    }

    /**
     * 实现错误路径,暂时无用
     *
     * @return
     */
    @Override
    public String getErrorPath() {
        return "";
    }
}

以上就是SpringBoot异常处理ErrorController详解，如果大家喜欢请一键三连。