Java参数校验

怼烎@ 2022-04-23 03:36 292阅读 0赞

**基本步骤**

1.  引入pom依赖
2.  书写需要校验的实体
3.  书写实体校验工具类
4.  编写测试代码

## 引入pom依赖 ##

<dependency>
                <groupId>javax.validation</groupId>
                <artifactId>validation-api</artifactId>
                <version>2.0.1.Final</version>
            </dependency>
            <dependency>
                <groupId>org.hibernate</groupId>
                <artifactId>hibernate-validator</artifactId>
                <version>6.0.14.Final</version>
            </dependency>
            <dependency>
                <groupId>org.glassfish</groupId>
                <artifactId>javax.el</artifactId>
                <version>3.0.1-b11</version>
            </dependency>

## 书写需要校验的实体 ##

package com.ahut.common.utils;
    
    import javax.validation.constraints.Min;
    import javax.validation.constraints.NotNull;
    
    /**
     * desc : 新增用户请求
     * create_user : cheng
     * create_date : 2019/1/23 11:34
     */
    public class AddUserRequest {
    
        /**
         * 用户名
         */
        @NotNull(message = "用户名不能为空")
        private String userName;
        /**
         * 年龄
         */
        @Min(value = 0, message = "用户年龄最小为0")
        private int age;
    
    
        public String getUserName() {
            return userName;
        }
    
        public void setUserName(String userName) {
            this.userName = userName;
        }
    
        public int getAge() {
            return age;
        }
    
        public void setAge(int age) {
            this.age = age;
        }
    }

## 书写实体校验工具类 ##

package com.ahut.common.utils;
    
    import com.ahut.common.entity.BeanValidateResult;
    import org.apache.commons.collections.CollectionUtils;
    
    import javax.validation.ConstraintViolation;
    import javax.validation.Validation;
    import javax.validation.Validator;
    import javax.validation.ValidatorFactory;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Set;
    import java.util.stream.Collectors;
    
    /**
     * desc : 实体校验工具类
     * create_user : cheng
     * create_date : 2019/1/23 13:54
     */
    public final class BeanValidateUtil {
    
        /**
         * 私有化构造方法
         */
        private BeanValidateUtil() {
        }
    
        /**
         * desc : 校验
         * create_user : cheng
         * create_date : 2019/1/23 13:56
         */
        public static <T> List<BeanValidateResult> validate(T bean) {
            // 校验null
            if (Objects.isNull(bean)) {
                return getNullValidateResultList();
            }
    
            // 获取验证器工厂
            ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();
            // 获取验证器
            Validator validator = validatorFactory.getValidator();
            // 执行验证
            Set<ConstraintViolation<T>> validateSet = validator.validate(bean);
            return getValidateResultList(validateSet);
        }
    
        /**
         * desc : 获取校验实体list
         * create_user : cheng
         * create_date : 2019/1/23 14:12
         */
        private static <T> List<BeanValidateResult> getValidateResultList(Set<ConstraintViolation<T>> validateSet) {
            List<BeanValidateResult> validateResultList = new ArrayList<>();
            if (CollectionUtils.isNotEmpty(validateSet)) {
                validateResultList = validateSet.stream().map(BeanValidateUtil::convertToBeanValidateResult).collect(Collectors.toList());
            }
            return validateResultList;
        }
    
        /**
         * desc : 转换类型
         * create_user : cheng
         * create_date : 2019/1/23 14:48
         */
        private static <T> BeanValidateResult convertToBeanValidateResult(ConstraintViolation<T> validate) {
            BeanValidateResult validateResult = new BeanValidateResult();
            validateResult.setFieldName(validate.getPropertyPath().toString());
            validateResult.setMessage(validate.getMessage());
            return validateResult;
        }
        /**
         * desc : 获取bean为null时的校验结果
         * create_user : cheng
         * create_date : 2019/1/24 10:39
         */
        private static List<BeanValidateResult> getNullValidateResultList() {
            List<BeanValidateResult> validateResultList = new ArrayList<>();
            BeanValidateResult validateResult = new BeanValidateResult();
            validateResult.setFieldName("validateBean");
            validateResult.setMessage("bean is null");
            validateResultList.add(validateResult);
            return validateResultList;
        }
    
    }

package com.ahut.common.entity;
    
    /**
     * desc : 参数校验结果封装实体
     * create_user : cheng
     * create_date : 2019/1/23 14:45
     */
    public class BeanValidateResult {
    
        private String fieldName;
    
        private String message;
    
        public String getFieldName() {
            return fieldName;
        }
    
        public void setFieldName(String fieldName) {
            this.fieldName = fieldName;
        }
    
        public String getMessage() {
            return message;
        }
    
        public void setMessage(String message) {
            this.message = message;
        }
    }

## 编写测试代码 ##

package com.ahut.common.utils;
    
    import com.ahut.common.entity.BeanValidateResult;
    import org.junit.Test;
    
    import java.util.List;
    
    /**
     * desc : 测试参数校验
     * create_user : cheng
     * create_date : 2019/1/23 14:21
     */
    public class BeanValidateUtilTest {
    
        /**
         * desc :
         * create_user : cheng
         * create_date : 2019/1/23 14:21
         */
        @Test
        public void testValidate() {
            AddUserRequest request = new AddUserRequest();
            request.setAge(-1);
    
            List<BeanValidateResult> validateResultList = BeanValidateUtil.validate(request);
            for (BeanValidateResult validateResult : validateResultList) {
                System.out.println(validateResult.getFieldName() + " : " + validateResult.getMessage());
            }
        }
    
    }

输出结果

userName : 用户名不能为空
    age : 用户年龄最小为0

## 自定义注解 ##

**定义注解**

package com.ahut.common.annotation;
    
    import com.ahut.common.annotation.validate.ListIsNotEmptyValidator;
    
    import javax.validation.Constraint;
    import javax.validation.Payload;
    import java.lang.annotation.ElementType;
    import java.lang.annotation.Retention;
    import java.lang.annotation.RetentionPolicy;
    import java.lang.annotation.Target;
    
    /**
     * desc : 校验list不为空的注解
     * create_user : cheng
     * create_date : 2019/1/24 16:33
     */
    @Target({ElementType.FIELD, ElementType.METHOD})
    @Retention(RetentionPolicy.RUNTIME)
    @Constraint(validatedBy = ListIsNotEmptyValidator.class)
    public @interface ListIsNotEmpty {
    
        String message() default "{com.ahut.common.annotation.ListIsNotEmpty.message}";
    
        Class<?>[] groups() default {};
    
        Class<? extends Payload>[] payload() default {};
    }

**定义注解校验器**

package com.ahut.common.annotation.validate;
    
    import com.ahut.common.annotation.ListIsNotEmpty;
    import org.apache.commons.collections.CollectionUtils;
    
    import javax.validation.ConstraintValidator;
    import javax.validation.ConstraintValidatorContext;
    import java.util.List;
    
    /**
     * desc : 验证ListIsNotEmpty注解
     * create_user : cheng
     * create_date : 2019/1/24 16:38
     */
    public class ListIsNotEmptyValidator implements ConstraintValidator<ListIsNotEmpty, List> {
    
        /**
         * desc :
         * create_user : cheng
         * create_date : 2019/1/24 16:49
         */
        @Override
        public boolean isValid(List list, ConstraintValidatorContext constraintValidatorContext) {
            return CollectionUtils.isNotEmpty(list);
        }
    
        /**
         * desc : 初始化
         * create_user : cheng
         * create_date : 2019/1/24 16:49
         */
        @Override
        public void initialize(ListIsNotEmpty constraintAnnotation) {
        }
    
    }