帮我们在页面共享信息;
@Override
public Map<String, Object> getErrorAttributes(RequestAttributes requestAttributes,
boolean includeStackTrace) {
Map<String, Object> errorAttributes = new LinkedHashMap<String, Object>();
errorAttributes.put("timestamp", new Date());
addStatus(errorAttributes, requestAttributes);
addErrorDetails(errorAttributes, requestAttributes, includeStackTrace);
addPath(errorAttributes, requestAttributes);
return errorAttributes;
}
@Controller
@RequestMapping("${server.error.path:${error.path:/error}}")
public class BasicErrorController extends AbstractErrorController {
@RequestMapping(produces = "text/html")//产生html类型的数据;浏览器发送的请求来到这个方法处理
public ModelAndView errorHtml(HttpServletRequest request,
HttpServletResponse response) {
HttpStatus status = getStatus(request);
Map<String, Object> model = Collections.unmodifiableMap(getErrorAttributes(
request, isIncludeStackTrace(request, MediaType.TEXT_HTML)));
response.setStatus(status.value());
//去哪个页面作为错误页面;包含页面地址和页面内容
ModelAndView modelAndView = resolveErrorView(request, response, status, model);
return (modelAndView == null ? new ModelAndView("error", model) : modelAndView);
}
@RequestMapping
@ResponseBody //产生json数据,其他客户端来到这个方法处理;
public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
Map<String, Object> body = getErrorAttributes(request,
isIncludeStackTrace(request, MediaType.ALL));
HttpStatus status = getStatus(request);
return new ResponseEntity<Map<String, Object>>(body, status);
}
@Value("${error.path:/error}")
private String path = "/error"; 系统出现错误以后来到error请求进行处理;(web.xml注册的错误页面规则)
4、DefaultErrorViewResolver:
@Override
public ModelAndView resolveErrorView(HttpServletRequest request, HttpStatus status,
Map<String, Object> model) {
ModelAndView modelAndView = resolve(String.valueOf(status), model);
if (modelAndView == null && SERIES_VIEWS.containsKey(status.series())) {
modelAndView = resolve(SERIES_VIEWS.get(status.series()), model);
}
return modelAndView;
}
private ModelAndView resolve(String viewName, Map<String, Object> model) {
//默认SpringBoot可以去找到一个页面? error/404
String errorViewName = "error/" + viewName;
//模板引擎可以解析这个页面地址就用模板引擎解析
TemplateAvailabilityProvider provider = this.templateAvailabilityProviders
.getProvider(errorViewName, this.applicationContext);
if (provider != null) {
//模板引擎可用的情况下返回到errorViewName指定的视图地址
return new ModelAndView(errorViewName, model);
}
//模板引擎不可用,就在静态资源文件夹下找errorViewName对应的页面 error/404.html
return resolveResource(errorViewName, model);
}
protected ModelAndView resolveErrorView(HttpServletRequest request,
HttpServletResponse response, HttpStatus status, Map<String, Object> model) {
//所有的ErrorViewResolver得到ModelAndView
for (ErrorViewResolver resolver : this.errorViewResolvers) {
ModelAndView modelAndView = resolver.resolveErrorView(request, status, model);
if (modelAndView != null) {
return modelAndView;
}
}
return null;
}
我们可以使用4xx和5xx作为错误页面的文件名来匹配这种类型的所有错误,精确优先(优先寻找精确的状态码.html);
页面能获取的信息;
属性名称 | 类型 |
---|---|
timestamp | 时间戳 |
status | 状态码 |
error | 错误提示 |
exception | 异常对象 |
message | 异常消息 |
errors | JSR303数据校验的错误都在这里 |
没有模板引擎(模板引擎找不到这个错误页面),静态资源文件夹下找;
以上都没有错误页面,就是默认来到SpringBoot默认的错误提示页面;
<h1>status:[[${status}]]h1>
<h2>时间戳:[[${timestamp}]]h2>
<h1>错误信息:[[${error}]]h1>
<h1>异常对象:[[${exception}]]h1>
<h1>异常信息:[[${message}]]h1>
<h1>JSR303数据校验的错误:[[${errors}]]h1>
public class NoUserExistException extends RuntimeException {
public NoUserExistException(){
super("该用户不存在");
}
}
@ControllerAdvice
public class MyExceptionHandler {
@ResponseBody
@ExceptionHandler(value= NoUserExistException.class)
public Map NoUserExistException(){
Map<String,Object> map = new HashMap<>();
map.put("code","user_noexist");
map.put("msg","用户不存在");
return map;
}
}
@ExceptionHandler(value = NoUserExistException.class)
public String NoUserExistException(Exception e, HttpServletRequest request) {
//设置请求状态码,否则无法跳转到对应页面
request.setAttribute("javax.servlet.error.status_code", 500);
Map<String, Object> map = new HashMap<>();
map.put("code", "user_noexist");
map.put("msg", e.getMessage());
return "forward:/error";
}
出现错误以后,会来到/error请求,会被BasicErrorController处理,响应出去可以获取的数据是由getErrorAttributes得到的(是AbstractErrorController(ErrorController)规定的方法);
容器中DefaultErrorAttributes.getErrorAttributes();默认进行数据处理的;
自定义ErrorAttributes
@Component
public class MyErrorAttributes extends DefaultErrorAttributes {
@Override
public Map<String, Object> getErrorAttributes(RequestAttributes requestAttributes, boolean includeStackTrace) {
Map<String, Object> map = getErrorAttributes(requestAttributes, includeStackTrace);
map.put("company","自定义数据");
return map;
}
}