Parameter Validation
- Feature Description
  - Maven Dependency
Usage Scenario
Usage Method
Feedback

Parameter Validation

Parameter validation in Dubbo

Feature Description

The parameter validation feature is implemented based on JSR303. Users only need to specify validation annotations from the JSR303 standard and implement validation through a declared filter.

Maven Dependency

<dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
    <version>1.0.0.GA</version>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>4.2.0.Final</version>
</dependency>

Usage Scenario

The server addresses various interface parameter validation issues when providing interface services externally.

Reference Case https://github.com/apache/dubbo-samples/tree/master/dubbo-samples-validation

Usage Method

Parameter Annotation Example

import java.io.Serializable;
import java.util.Date;
import javax.validation.constraints.Future;
import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Past;
import javax.validation.constraints.Pattern;
import javax.validation.constraints.Size;
public class ValidationParameter implements Serializable {
    private static final long serialVersionUID = 7158911668568000392L;
    @NotNull // Cannot be null
    @Size(min = 1, max = 20) // Length or size range
    private String name;
    @NotNull(groups = ValidationService.Save.class) // Cannot be null when saving, can be null when updating, indicating no update to this field
    @Pattern(regexp = "^\\s*\\w+(?:\\.{0,1}[\\w-]+)*@[a-zA-Z0-9]+(?:[-.][a-zA-Z0-9]+)*\\.[a-zA-Z]+\\s*$")
    private String email;
    @Min(18) // Minimum value
    @Max(100) // Maximum value
    private int age;
    @Past // Must be a past date
    private Date loginDate;
    @Future // Must be a future date
    private Date expiryDate;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public Date getLoginDate() {
        return loginDate;
    }
    public void setLoginDate(Date loginDate) {
        this.loginDate = loginDate;
    }
    public Date getExpiryDate() {
        return expiryDate;
    }
    public void setExpiryDate(Date expiryDate) {
        this.expiryDate = expiryDate;
    }
}

Group Validation Example

public interface ValidationService { // Default can differentiate validation scenarios by service interface, e.g., @NotNull(groups = ValidationService.class)   
    @interface Save{} // Interface name same as method, capitalized first letter, used to differentiate validation scenarios, e.g., @NotNull(groups = ValidationService.Save.class), optional
    void save(ValidationParameter parameter);
    void update(ValidationParameter parameter);
}

import javax.validation.GroupSequence;
public interface ValidationService {   
    @GroupSequence(Update.class) // Validate Update group rules simultaneously
    @interface Save{}
    void save(ValidationParameter parameter);
    @interface Update{} 
    void update(ValidationParameter parameter);
}

Parameter Validation Example

import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
public interface ValidationService {
    void save(@NotNull ValidationParameter parameter); // Validate parameter is not null
    void delete(@Min(1) int id); // Directly validate basic type parameter
}

Validate Parameters on Client

<dubbo:reference id="validationService" interface="org.apache.dubbo.examples.validation.api.ValidationService" validation="true" />

Validate Parameters on Server

<dubbo:service interface="org.apache.dubbo.examples.validation.api.ValidationService" ref="validationService" validation="true" />

Dubbo supports hibernate-validator version <=6.x by default. If using hibernate-validator version 7.x, declare the validation parameter as jvalidationNew.

Validation Exception Information

import javax.validation.ConstraintViolationException;
import javax.validation.ConstraintViolationException;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.apache.dubbo.examples.validation.api.ValidationParameter;
import org.apache.dubbo.examples.validation.api.ValidationService;
import org.apache.dubbo.rpc.RpcException;
public class ValidationConsumer {   
    public static void main(String[] args) throws Exception {
        String config = ValidationConsumer.class.getPackage().getName().replace('.', '/') + "/validation-consumer.xml";
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(config);
        context.start();
        ValidationService validationService = (ValidationService)context.getBean("validationService");
        // Error
        try {
            parameter = new ValidationParameter();
            validationService.save(parameter);
            System.out.println("Validation ERROR");
        } catch (RpcException e) { // Throws RpcException
            ConstraintViolationException ve = (ConstraintViolationException) e.getCause(); // Inside is a nested ConstraintViolationException
            Set<ConstraintViolation<?>> violations = ve.getConstraintViolations(); // Can get a collection of detailed validation error information
            System.out.println(violations);
        }
    } 
}