JSR303 does not correspond to the specified jar package, but a specification. At present, hibernate validator is the most used implementation based on JSR303 specification

This article is not suitable for newcomers. It is required to know at least how to use it

Springboot integrates the starter launcher of JSR303

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

Normally reference the dependency of Hibernate validator

<!-- 6.2.0.Final Is the recommended version -->
<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.2.0.Final</version>
</dependency>

Common annotation records

Some common annotations are recorded here, not all of which will be supplemented at any time

Notes brief introduction

Each annotation contains common attributes. Here we introduce message and groups:

Value type verification

Range type verification

Custom verification annotation

To customize a verification annotation, you need to create an annotation, and then add three basic attributes that each verification annotation has

@Documented
@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE })
@Retention(RUNTIME)
public @interface Phone {

    String message() default "";

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

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

}

Now the annotation is created, but it is a useless empty shell annotation. If you want it to have the ability of verification, you need a class to help him complete the verification. Use the @ Constraint annotation to specify which class to help him complete the verification

@Documented
@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE })
@Retention(RUNTIME)
// Indicates that you want to use PhoneValidate to complete the verification for yourself
@Constraint(validatedBy = PhoneValidate.class)
public @interface Phone { ... }

Next, create a PhoneValidate class to help the annotation complete the verification rules

// This class must implement the ConstraintValidator interface. Phone in the generic type represents the effective annotation, and String represents the type of the annotated attribute
public class PhoneValidate implements ConstraintValidator<Phone, String> {

    // private String pattern;

    @Override
    public void initialize(Phone annotation) {
        // Here, the execution priority is high. The value carried in the annotation can be obtained through annotation for subsequent verification processing, for example:
        // this.pattern = annotation.pattern();
    }

    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        // Determine whether the verification passes by returning true or false
        String regExp = "^((13[0-9])|(14[5,7,9])|(15[0-3,5-9])|(166)|(17[3,5,6,7,8])|(18[0-9])|(19[8,9]))\\d{8}$";
        return value.matches(regExp);
    }

}

This completes the custom validation annotation