自定义Java Validator

在项目中，针对汉字的长度计算，数据库和java的计算方式不一致，需要重新处理下java 的 Validator，使其满足项目

建立自定义的 validator annotation

@Target({METHOD, FIELD})

@Retention(RUNTIME)

@Documented

@Constraint(validatedBy = SizeValidator.class)		// 对应的验证class

public @interface DbSize {

    String message() default "{javax.validation.constraints.Size.message}";

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

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

    /**

     * @return size the element must be higher or equal to

     */

    int min() default 0;

    /**

     * @return size the element must be lower or equal to

     */

    int max() default Integer.MAX_VALUE;

}

创建验证的执行类

public class DbSizeValidator implements ConstraintValidator<DbSize, String> {

    @Value("${db.charset:GBK}")

    private String charset;

    private DbSize size;

    @Override

    public void initialize(DbSize constraintAnnotation) {

        this.size = constraintAnnotation;

    }

    /**

     * Implements the validation logic.

     * The state of {@code value} must not be altered.

     * <p>

     * This method can be accessed concurrently, thread-safety must be ensured

     * by the implementation.

     *

     * @param value   object to validate

     * @param context context in which the constraint is evaluated

     * @return {@code false} if {@code value} does not pass the constraint

     */

    @Override

    public boolean isValid(String value, ConstraintValidatorContext context) {

        if (value == null || "".equals(value)) {

            return size.min() == 0 ? true : false;

        }

        int length = 0;

        try {

            length = value.getBytes(charset).length;

        } catch (Exception e) {

            try {

                length = value.getBytes(Charset.forName("GBK")).length;

            } catch (Exception e1){

                // 如果失败，jvm就直接狗带了，不需要了

                length = value.getBytes().length;

            }

        }

        return (length > size.max() || length < size.min()) ? false : true;

    }

}

测试

public class DbSizeValidatorTest {

    @Test

    public void validatorTest() {

        ValidationModel model = new ValidationModel();

        ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();

        Validator validator = validatorFactory.getValidator();

        Set<ConstraintViolation<ValidationModel>> validate = validator.validate(model);

        List<String> messageList = new ArrayList<>();

        for (ConstraintViolation<ValidationModel> constraintViolation : validate) {

            messageList.add(constraintViolation.getMessage());

        }

        Assertions.assertEquals(true, messageList.stream().map(el -> "请使用类型".equals(el)).count() == 1);

        messageList.stream().forEach(System.out::println);

    }

    @Data

    private class ValidationModel {

        @DbSize(max = 2, message = "请使用类型")

        private String xdoSize = "错误";

        @DbSize(max = 2, message = "xdoSize正确")

        private String xdoSize1 = "对";

        @DbSize(max = 5, message = "xdoSizeEn正确")

        private String xdoSize2 = "对aB2";

    }

}

巴特西

自定义Java Validator

自定义Java Validator

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