springboot validation 自定义验证注解

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springboot validation 自定义验证注解

 

应用：自定义注解对pojo进行检验

 

 

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相关类与接口

 

ConstraintValidator：自定义注解对应验证规则

public interface ConstraintValidator<A extends Annotation, T> {
    default void initialize(A constraintAnnotation) {
    }

    boolean isValid(T var1, ConstraintValidatorContext var2);
}

第一个参数A表示验证注解，第二个参数T表示注解标注的对象

 

@Length

@Documented
@Constraint(
    validatedBy = {}
)
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER, ElementType.TYPE_USE})
@Retention(RetentionPolicy.RUNTIME)
@Repeatable(Length.List.class)
public @interface Length {
    int min() default 0;

    int max() default 2147483647;

    String message() default "{org.hibernate.validator.constraints.Length.message}";

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

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

    @Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER, ElementType.TYPE_USE})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface List {
        Length[] value();
    }
}

 

LengthValidator：长度验证器

public class LengthValidator implements ConstraintValidator<Length, CharSequence> {
    private static final Log LOG = LoggerFactory.make(MethodHandles.lookup());
    private int min;
    private int max;

    public LengthValidator() {
    }

    public void initialize(Length parameters) {
        this.min = parameters.min();
        this.max = parameters.max();
        this.validateParameters();
    }

    public boolean isValid(CharSequence value, ConstraintValidatorContext constraintValidatorContext) {
        if (value == null) {
            return true;
        } else {
            int length = value.length();
            return length >= this.min && length <= this.max;
        }
    }

    private void validateParameters() {
        if (this.min < 0) {
            throw LOG.getMinCannotBeNegativeException();
        } else if (this.max < 0) {
            throw LOG.getMaxCannotBeNegativeException();
        } else if (this.max < this.min) {
            throw LOG.getLengthCannotBeNegativeException();
        }
    }
}

 

 

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示例：定义类验证注解，检验price*amount、totalFee的差值

 

********************

validation 层

 

@CheckNum

@Documented
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = {CustomValidator.class})
@Target({ElementType.TYPE,ElementType.ANNOTATION_TYPE})
public @interface CheckNum {

    String field();
    String field2();
    String field3();

    String message() default "{org.hibernate.validator.constraints.Length.message}";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
}

 

CustomValidator

public class CustomValidator implements ConstraintValidator<CheckNum, Object> {

    private String field;
    private String field2;
    private String field3;

    @Override
    public void initialize(CheckNum constraintAnnotation) {
        this.field=constraintAnnotation.field();
        this.field2=constraintAnnotation.field2();
        this.field3=constraintAnnotation.field3();
    }

    @Override
    public boolean isValid(Object o, ConstraintValidatorContext constraintValidatorContext) {
        BeanWrapper beanWrapper=new BeanWrapperImpl(o);
        Double price=Double.parseDouble(Objects.requireNonNull(Objects.requireNonNull(beanWrapper.getPropertyValue(field)).toString()));
        Integer amount=Integer.parseInt(Objects.requireNonNull(Objects.requireNonNull(beanWrapper.getPropertyValue(field2)).toString()));
        double totalFee=Double.parseDouble(Objects.requireNonNull(Objects.requireNonNull(beanWrapper.getPropertyValue(field3)).toString()));

        return Math.abs(totalFee-price*amount)<0.01;
    }
}

 

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pojo 层

 

Order

@Data
@CheckNum(field = "price",field2 = "amount",field3 = "totalFee",message = "totalFee 与 price*amount数值相差超过0.01")
public class Order {

    private Double price;
    private Integer amount;
    private Double totalFee;
}

 

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controller 层

 

HelloController

@RestController
public class HelloController {

    @RequestMapping("/hello")
    public String hello(@Validated Order order, BindingResult result){
        System.out.println(order);

        if (result.hasErrors()){
            result.getAllErrors().forEach(error -> {
                System.out.print("field："+error.getObjectName());
                System.out.println(" ==> message："+error.getDefaultMessage());
            });
        }

        return "success";
    }
}

 

 

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使用测试

 

localhost:8080/hello?price=2&amount=8&totalFee=8

2020-07-15 11:53:21.378  INFO 340 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2020-07-15 11:53:21.382  INFO 340 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : Completed initialization in 4 ms
Order(price=2.0, amount=8, totalFee=8.0)
field：order ==> message：totalFee 与 price*amount数值相差超过0.01

 

 

本文地址：https://blog.csdn.net/weixin_43931625/article/details/107343789