@ControllerAdvice和ErrorController的用法

在Java中异常可以分为Error和Exception，@ControllerAdvice用来处理系统中的Exception，ErrorController处理系统中的Error。

1.ErrorController

当系统出现404或者405等错误信息时，springboot默认的访问路径为/error，所以实现ErrorController并重写

getErrorPath方法

@Controller
public class AppErrorController implements ErrorController{

    private static final String ERROR_PATH = "/error";

    @Autowired
    private ErrorAttributes errorAttributes;

    @Override
    public String getErrorPath() {
        return ERROR_PATH;
    }

   /* @Autowired
    private AppErrorController(ErrorAttributes errorAttributes){
        this.errorAttributes = errorAttributes;
    }*/

    /**
     * web页面错误处理
     * @param request
     * @param response
     * @return
     */
    @RequestMapping(value = ERROR_PATH,produces = "text/html")
    public String errorPageHandler(HttpServletRequest request, HttpServletResponse response){
        int status = response.getStatus();
        switch (status) {
            case 403:
                return "403";
            case 404:
                return "404";
            case 500:
                return "500";
        }

        return "index";
    }

    /**
     * 除web页面外的错误处理，如JSON/XML等
     */
    @RequestMapping(value = ERROR_PATH)
    @ResponseBody
    public ApiResponse errorApiHandler(HttpServletRequest request){
        RequestAttributes requestAttributes = new ServletRequestAttributes(request);
        Map<String, Object> attr = this.errorAttributes.getErrorAttributes(requestAttributes, false);
        int status = getStatus(request);
        return ApiResponse.ofMessage(status, String.valueOf(attr.getOrDefault("message", "error")));
    }

    private int getStatus(HttpServletRequest request) {
        Integer status = (Integer) request.getAttribute("javax.servlet.error.status_code");//固定写法
        if (status != null) {
            return status;
        }
        return 500;
    }
}

2.ControllerAdvice

ControllerAdvice用来处理发生Exception错误的注解。需要注意的是不能使用try catch 捕获

@ControllerAdvice
public class GlobalExceptionHandler {

    private static Logger logger = LoggerFactory.getLogger(GlobalExceptionHandler.class);

    @ExceptionHandler(value = {Exception.class,NullPointerException.class})//这里可以写多个异常
    public ApiResponse exceptionHandler(HttpServletRequest request, Exception e, HttpServletResponse response){
        int status = response.getStatus();
        return ApiResponse.ofMessage(status, e.getMessage());
    }
}