java 自定义注解之ElementType.PARAMETER

@Api("项目管理")
@RestController
@RequestMapping("/project")
@Validated
public class ProjectController extends BaseController {

@ApiOperation(value = "获取项目管理列表", response = ProjectInfoVO.class)
@GetMapping("/list")
public ResultMessage queryProjectList(@OrderBy @ApiParam(value = "已结算数量排序(选填 值为desc/asc)") @RequestParam(value = "packagePayedAmount", required = false) String orderPackagePayedAmount,
                                          @ApiParam(value = "分页数量") @RequestParam(value = "pageSize", defaultValue = "10") int pageSize,
                                          @ApiParam(value = "页码") @RequestParam(value = "pageNo", defaultValue = "1") int pageNo) {


        ResultMessage resultMessage = new ResultMessage();

        //....

        return resultMessage;
    }
}

package com.antzb.chaos.annotations;

import javax.validation.Constraint;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import javax.validation.Payload;
import java.lang.annotation.*;

/**
 * @Author: qubianzhong
 * @Date: 18-4-12 下午1:38
 */
@Documented
@Target({ElementType.PARAMETER, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = OrderBy.OrderByValidator.class)
public @interface OrderBy {

    String message() default "{只能为　DESC 或者 ASC}";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};

    class OrderByValidator implements ConstraintValidator<OrderBy, String> {

        @Override
        public void initialize(OrderBy constraintAnnotation) {
        }

        @Override
        public boolean isValid(String value, ConstraintValidatorContext context) {
            boolean isValid = true;
            if (value != null && !"DESC".equals(value.toUpperCase()) && !"ASC".equals(value.toUpperCase())) {
                isValid = false;
            }
            return isValid;
        }
    }
}