validate

Posted 2020-12-05 brxhqs

package com.brx.utils;

import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.brx.exception.ParamException;
import org.apache.commons.collections.MapUtils;

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
import java.util.*;

public class BeanValidator {

　　//1.创建validator工厂
    private static ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();

    public static <T> Map<String, String> validate(T t, Class... groups) {
　　　　//2.获取Validator
        Validator validator = validatorFactory.getValidator();
　　　　//3.校验  获得的Set<ConstraintViolation> -----约束违反的set集合
        Set validateResult = validator.validate(t, groups);//这个gropus感觉没什么用，主要是为了迎合参数列表,另外，t不能使集合类型
        if (validateResult.isEmpty()) {
            return Collections.emptyMap();
        } else {
            LinkedHashMap errors = Maps.newLinkedHashMap();
            Iterator iterator = validateResult.iterator();
            while (iterator.hasNext()) {
                ConstraintViolation violation = (ConstraintViolation)iterator.next();
　　　　　　　　　　4.封装结果集  （属性值-错误信息）-》(violation.getPropertyPath().toString(),violation.getMessage())
                errors.put(violation.getPropertyPath().toString(), violation.getMessage());
            }
            return errors;
        }
    }

//对一个集合类型进行遍历校验，上面的validate方法，不能处理集合类型
    public static Map<String, String> validateList(Collection<?> collection) {
        Preconditions.checkNotNull(collection);
        Iterator iterator = collection.iterator();
        Map errors;

        do {
            if (!iterator.hasNext()) {
                return Collections.emptyMap();
            }
            Object object = iterator.next();
            errors = validate(object, new Class[0]);
        } while (errors.isEmpty());//只要集合内有一个字段错误，那么直接返回，不用考虑剩余元素

        return errors;
    }

//通用方法，至少传入一个Object参数，这个方法还是有问题，如果first为集合就

//  BeanValidator.validateObject(testVo,testVo,testVo);
public static Map<String, String> validateObject(Object first, Object... objects) {
    if (objects != null && objects.length > 0) {
        return validateList(Lists.asList(first, objects));
    } else if(first instanceof Collection){
       return validateList((Collection)first);
    }else{
        return validate(first, new Class[0]);//这个Class[] x = new Class[0];x里面没有东西
    }
}

//最终方法：可以检验任何
    public static void check(Object param) throws ParamException {//BeanValidator->controller->handlerExcetionResolver
        //异常层层向上抛出
        Map<String, String> map = BeanValidator.validateObject(param);
        if (MapUtils.isNotEmpty(map)) {
            throw new ParamException(map.toString());//自定义异常向上抛出
　　　　　　　　//日志打印等后续工作......
        }
    }

}