之前针对参数校验提供了一个通用方案（见文末），但是新增一个校验代价比较大，需要修改多个类。
给出一个改进方案，新增校验时只需新增一个校验类即可，并且校验可以指定分组。
这样同样的一个组件，可以实现多个分组，指定分组条件可以让不同的方法只走指定分组的校验。
package com.chujianyun.entity.param;
import lombok.Data;
@Data
public class UserParam {
private Long userId;
private Integer level;
}枚举
package com.chujianyun.entity.enums;
public enum UserValidateGroupEnum {
// 所有条件都校验
ALL,
// 某种条件才校验
SOME
}结果类
package com.chujianyun.entity.dto;
import lombok.Data;
import java.util.List;
@Data
public class UserDTO {
private String message;
public UserDTO() {
}
public UserDTO(String message) {
this.message = message;
}
}package com.chujianyun.component; import lombok.Data; import java.util.Set; @Data public abstract class Validator{ private Set
groups; abstract void validate(P param); }
等级校验
package com.chujianyun.component; import com.chujianyun.entity.param.UserParam; import com.chujianyun.exception.BusinessException; import org.apache.commons.lang3.RandomUtils; import org.springframework.stereotype.Component; @Component public class UserLevelValidator extends Validator{ @Override public void validate(UserParam param) { System.out.println("验证等级"); if (param == null) { throw new BusinessException(""); } // 根据userId查询等级 boolean isBiggerThan50 = RandomUtils.nextBoolean(); if (!isBiggerThan50) { throw new BusinessException("低于50级"); } } }
性别校验
package com.chujianyun.component; import com.chujianyun.entity.param.UserParam; import com.chujianyun.exception.BusinessException; import org.apache.commons.lang3.RandomUtils; import org.springframework.stereotype.Component; @Component public class UserSexValidator extends Validator{ @Override void validate(UserParam param) { System.out.println("验证性别"); if (param == null) { throw new BusinessException(""); } // 模拟服务，根据userId查询性别 boolean isFemale = RandomUtils.nextBoolean(); if (!isFemale) { throw new BusinessException("仅限女性玩家哦！"); } } }
某个特殊类型校验
package com.chujianyun.component; import com.chujianyun.entity.enums.UserValidateGroupEnum; import com.chujianyun.entity.param.UserParam; import com.chujianyun.exception.BusinessException; import org.apache.commons.collections4.SetUtils; import org.apache.commons.lang3.RandomUtils; import org.springframework.stereotype.Component; import javax.annotation.PostConstruct; import java.util.HashSet; import java.util.stream.Collectors; import java.util.stream.Stream; @Component public class UserSomevalidator extends Validator{ @PostConstruct public void init() { setGroups(Stream.of(UserValidateGroupEnum.SOME).collect(Collectors.toSet())); } @Override void validate(UserParam param) { System.out.println("仅检测Some类型的"); if (param == null) { throw new BusinessException(""); } // 模拟服务，根据userId某个条件 boolean isSome = RandomUtils.nextBoolean(); if (!isSome) { throw new BusinessException("某种条件不满足哦！"); } } }
package com.chujianyun.component;
import org.apache.commons.collections4.CollectionUtils;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.ResolvableType;
import org.springframework.stereotype.Component;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Predicate;
import java.util.stream.Collectors;
@Component
public class ValidatorChain implements ApplicationContextAware {
private Map> validatorMap = new HashMap<>();
public void checkParam(P param) {
checkParam(param, validator -> true);
}
public
void checkParam(P param, Predicate predicate) {
List validators = getValidators(param.getClass());
if (CollectionUtils.isNotEmpty(validators)) {
validators.stream()
.filter(predicate)
.forEach(validator -> validator.validate(param));
}
}
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
Map beansOfType = applicationContext.getBeansOfType(Validator.class);
this.validatorMap = beansOfType.values().stream().collect(Collectors.groupingBy(validator -> getParamType(validator.getClass())));
}
private List getValidators(Class clazz) {
return validatorMap.get(clazz);
}
private Class getParamType(Class clazz) {
ResolvableType resolvableType = ResolvableType.forClass(clazz);
return resolvableType.getSuperType().getGeneric(0).resolve();
}
}
package com.chujianyun.service;
import com.chujianyun.entity.dto.UserDTO;
import com.chujianyun.entity.param.UserParam;
public interface UserService {
UserDTO checkUser(UserParam userParam);
UserDTO checkUserSome(UserParam userParam);
}服务实现
package com.chujianyun.service.impl;
import com.chujianyun.component.ValidatorChain;
import com.chujianyun.entity.dto.UserDTO;
import com.chujianyun.entity.enums.UserValidateGroupEnum;
import com.chujianyun.entity.param.UserParam;
import com.chujianyun.service.UserService;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service
public class UserServiceImpl implements UserService {
@Resource
private ValidatorChain validatorChain;
@Override
public UserDTO checkUser(UserParam userParam) {
// 参数校验
validatorChain.checkParam(userParam);
// 业务逻辑
return new UserDTO("测试");
}
@Override
public UserDTO checkUserSome(UserParam userParam) {
// 参数校验(只校验类型为Some的)
validatorChain
.checkParam(userParam, param -> param.getGroups()
.contains(UserValidateGroupEnum.SOME));
// 业务逻辑
return new UserDTO("测试");
}
}还可以设置除了分组之外的其他条件，满足条件才会校验。
2.7 控制层package com.chujianyun.web;
import com.chujianyun.entity.dto.UserDTO;
import com.chujianyun.entity.param.UserParam;
import com.chujianyun.service.UserService;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
@RequestMapping("/user")
public class HelloController {
@Resource
private UserService userService;
@PostMapping("/check")
public ResponseEntity checkUser(UserParam userParam) {
return new ResponseEntity<>(userService.checkUser(userParam), HttpStatus.OK);
}
@PostMapping("/checkSome")
public ResponseEntity checkUserSome(UserParam userParam) {
return new ResponseEntity<>(userService.checkUserSome(userParam), HttpStatus.OK);
}
} 2.8 异常处理
package com.chujianyun.web;
import com.chujianyun.exception.BusinessException;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
@ControllerAdvice
public class MyExceptionHandler {
@ExceptionHandler(value = Exception.class)
public ResponseEntity handle(Exception e) {
if (e instanceof BusinessException) {
return new ResponseEntity<>("[业务异常]" + e.getMessage(), HttpStatus.BAD_REQUEST);
}
return new ResponseEntity<>("[系统异常]" + e.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR);
}
}直接执行check校验所有的校验器（下面只给出其中一种情况的截图）
checkSome则只会校验指定的条件
四、总结
设计模式里有一个开闭原则即“对拓展开放，对修改关闭”，本例就是一个实践。
不过还有很多可以改进的地方，大家可以考虑使用接口来实现，欢迎大家一起完善，欢迎提PR。
大家在平时开发时，要多尝试将设计模式使用到项目中，来提高代码的可维护性，灵活性。
源码地址：https://github.com/chujianyun/checkparam
之前的一个通用方案：https://blog.csdn.net/w605283073/article/details/95680896
