import lombok.SneakyThrows;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.StringUtils;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import javax.servlet.http.HttpServletRequest;
import java.util.Optional;

/**
 * 全局異常處理器
 */
@RestControllerAdvice
public class GlobalExceptionHandler {

    public final Logger logger = LoggerFactory.getLogger(this.getClass());

    /**
     * 攔截參數(shù)驗(yàn)證異常
     */
    @SneakyThrows
    @ExceptionHandler(value = MethodArgumentNotValidException.class)
    public AjaxResult validExceptionHandler(HttpServletRequest request, MethodArgumentNotValidException ex) {
        BindingResult bindingResult = ex.getBindingResult();
        FieldError firstFieldError = CollectionUtil.getFirst(bindingResult.getFieldErrors());
        String exceptionStr = Optional.ofNullable(firstFieldError)
                .map(FieldError::getDefaultMessage)
                .orElse(StrUtil.EMPTY);
        logger.error("[{}] {} [ex] {}", request.getMethod(), getUrl(request), exceptionStr);
        return AjaxResult.error(exceptionStr);
    }

    /**
     * 攔截業(yè)務(wù)異常
     * BusinessServiceException 是一個(gè)自定義異常，以你們項(xiàng)目中的自定義異常為準(zhǔn)，如果沒有可以不寫
     */
    @ExceptionHandler(value = {BusinessServiceException.class})
    public AjaxResult handleBusinessException(HttpServletRequest request, BusinessServiceException ex){
        String exceptionStr = ex.getMessage();
        logger.error("[{}] {} [ex] {}", request.getMethod(), getUrl(request), exceptionStr);
        return AjaxResult.error(exceptionStr);
    }

    /**
     * 攔截未捕獲異常
     */
    @ExceptionHandler(Throwable.class)
    public AjaxResult defaultErrorHandler(HttpServletRequest request, Throwable throwable) {
        logger.error("[{}] {} ", request.getMethod(), getUrl(request), throwable);
        return AjaxResult.error(throwable.getMessage());
    }

    private String getUrl(HttpServletRequest request) {
        if (StringUtils.isEmpty(request.getQueryString())) {
            return request.getRequestURL().toString();
        }
        return request.getRequestURL().toString() + "?" + request.getQueryString();
    }
}

import lombok.Data;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

@Data
public class UserEntity {

    @NotNull(message = "用戶ID不能為空")
    private Long userId;

    @NotNull(message = "用戶名不能為空")
    @Size(min = 2, max = 30, message = "用戶名長(zhǎng)度必須在2到30個(gè)字符之間")
    private String username;
    
}

// 注意，這個(gè)方法我們并沒有采取任何 try catch 操作
@PostMapping("/test")
public AjaxResult Test(HttpServletRequest request, @RequestBody @Valid UserEntity userEntity) {
        Map<String,Object> model = new HashMap<String,Object>();
        String planCode = request.getParameter("planCode");
        String planDefineId = request.getParameter("planDefineId");
        if (StringUtils.isBlank(planDefineId) || StringUtils.isBlank(planCode)) {
            throw new BusinessServiceException("參數(shù)不可以為空！");
        }
        // 獲取信息
        String planName = retailProductCommon.getproductName(planCode, planDefineId);
        model.put("planName", planName);
        return AjaxResult.success(model);
}