002-异常处理

一、概述

　　在spring 体系中，异常处理有如下:https://www.cnblogs.com/bjlhx/p/8666653.html

　　可以结合jsr303使用：https://www.cnblogs.com/bjlhx/p/10305344.html

二、请求参数类异常

　　结合以上两种以及上文api设计原则修改响应数据，将请求参数类异常定位到http响应吗为4XX类，如下

@ControllerAdvice
public class GlobalExceptionHandler {


    @ExceptionHandler(value = ConstraintViolationException.class)
    @ResponseBody
    public ResponseEntity constraintViolationExceptionHandler(Exception e) {
        Map<String,Object> result=new HashMap();
        result.put("code",400);
        result.put("msg",e.getMessage());
        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(result);
    }

    @ExceptionHandler(value = javax.validation.UnexpectedTypeException.class)
    @ResponseBody
    public ResponseEntity unexpectedTypeExceptionHandler(Exception e) {
        Map<String,Object> result=new HashMap();
        result.put("code",400);
        result.put("msg",e.getMessage());
        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(result);
    }

    @ExceptionHandler(value = org.springframework.http.converter.HttpMessageNotReadableException.class)
    @ResponseBody
    public ResponseEntity httpMessageNotReadableExceptionHandler(Exception e) {
        Map<String,Object> result=new HashMap();
        result.put("code",400);
        result.put("msg","没有请求体，详细："+e.getMessage());
        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(result);
    }


    @ExceptionHandler(value = org.springframework.web.bind.MethodArgumentNotValidException.class)
    @ResponseBody
    public ResponseEntity methodArgumentNotValidExceptionHandler(MethodArgumentNotValidException e) {
        Map<String,Object> result=new HashMap();
        result.put("code",400);
        result.put("msg","请求体校验失败，详细："+e.getMessage());
        if (e.getBindingResult().hasErrors()) {
            List<FieldError> fieldErrors = e.getBindingResult().getFieldErrors();
            result.put("data",fieldErrors);
            return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(result);
        }
        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(result);
    }
    @ExceptionHandler(value = Exception.class)
    public void errorHandler(Exception e,HttpServletResponse response) throws IOException {
        response.sendError(HttpStatus.BAD_REQUEST.value());
    }
}

可以参看：https://blog.jayway.com/2014/10/19/spring-boot-error-responses/