参数验证

参数验证功能 [1] 是基于 JSR303 实现的，用户只需标识 JSR303 标准的验证 annotation，并通过声明 filter 来实现验证 [2]。

Maven 依赖

  1. <dependency>
  2.     <groupId>javax.validation</groupId>
  3.     <artifactId>validation-api</artifactId>
  4.     <version>1.0.0.GA</version>
  5. </dependency>
  6. <dependency>
  7.     <groupId>org.hibernate</groupId>
  8.     <artifactId>hibernate-validator</artifactId>
  9.     <version>4.2.0.Final</version>
  10. </dependency>

示例

参数标注示例

  1. import java.io.Serializable;
  2. import java.util.Date;
  4. import javax.validation.constraints.Future;
  5. import javax.validation.constraints.Max;
  6. import javax.validation.constraints.Min;
  7. import javax.validation.constraints.NotNull;
  8. import javax.validation.constraints.Past;
  9. import javax.validation.constraints.Pattern;
  10. import javax.validation.constraints.Size;
  12. public class ValidationParameter implements Serializable {
  13.     private static final long serialVersionUID = 7158911668568000392L;
  15.     @NotNull // 不允许为空
  16.     @Size(min = 1, max = 20) // 长度或大小范围
  17.     private String name;
  19.     @NotNull(groups = ValidationService.Save.class) // 保存时不允许为空，更新时允许为空 ，表示不更新该字段
  20.     @Pattern(regexp = "^\\s*\\w+(?:\\.{0,1}[\\w-]+)*@[a-zA-Z0-9]+(?:[-.][a-zA-Z0-9]+)*\\.[a-zA-Z]+\\s*$")
  21.     private String email;
  23.     @Min(18) // 最小值
  24.     @Max(100) // 最大值
  25.     private int age;
  27.     @Past // 必须为一个过去的时间
  28.     private Date loginDate;
  30.     @Future // 必须为一个未来的时间
  31.     private Date expiryDate;
  33.     public String getName() {
  34.         return name;
  35.     }
  37.     public void setName(String name) {
  38.         this.name = name;
  39.     }
  41.     public String getEmail() {
  42.         return email;
  43.     }
  45.     public void setEmail(String email) {
  46.         this.email = email;
  47.     }
  49.     public int getAge() {
  50.         return age;
  51.     }
  53.     public void setAge(int age) {
  54.         this.age = age;
  55.     }
  57.     public Date getLoginDate() {
  58.         return loginDate;
  59.     }
  61.     public void setLoginDate(Date loginDate) {
  62.         this.loginDate = loginDate;
  63.     }
  65.     public Date getExpiryDate() {
  66.         return expiryDate;
  67.     }
  69.     public void setExpiryDate(Date expiryDate) {
  70.         this.expiryDate = expiryDate;
  71.     }
  72. }

分组验证示例

  1. public interface ValidationService { // 缺省可按服务接口区分验证场景，如：@NotNull(groups = ValidationService.class)   
  2.     @interface Save{} // 与方法同名接口，首字母大写，用于区分验证场景，如：@NotNull(groups = ValidationService.Save.class)，可选
  3.     void save(ValidationParameter parameter);
  4.     void update(ValidationParameter parameter);
  5. }

关联验证示例

  1. import javax.validation.GroupSequence;
  3. public interface ValidationService {   
  4.     @GroupSequence(Update.class) // 同时验证Update组规则
  5.     @interface Save{}
  6.     void save(ValidationParameter parameter);
  8.     @interface Update{} 
  9.     void update(ValidationParameter parameter);
  10. }

参数验证示例

  1. import javax.validation.constraints.Min;
  2. import javax.validation.constraints.NotNull;
  4. public interface ValidationService {
  5.     void save(@NotNull ValidationParameter parameter); // 验证参数不为空
  6.     void delete(@Min(1) int id); // 直接对基本类型参数验证
  7. }

配置

在客户端验证参数

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

在服务器端验证参数

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

验证异常信息

  1. import javax.validation.ConstraintViolationException;
  2. import javax.validation.ConstraintViolationException;
  4. import org.springframework.context.support.ClassPathXmlApplicationContext;
  6. import org.apache.dubbo.examples.validation.api.ValidationParameter;
  7. import org.apache.dubbo.examples.validation.api.ValidationService;
  8. import org.apache.dubbo.rpc.RpcException;
  10. public class ValidationConsumer {   
  11.     public static void main(String[] args) throws Exception {
  12.         String config = ValidationConsumer.class.getPackage().getName().replace('.', '/') + "/validation-consumer.xml";
  13.         ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(config);
  14.         context.start();
  15.         ValidationService validationService = (ValidationService)context.getBean("validationService");
  16.         // Error
  17.         try {
  18.             parameter = new ValidationParameter();
  19.             validationService.save(parameter);
  20.             System.out.println("Validation ERROR");
  21.         } catch (RpcException e) { // 抛出的是RpcException
  22.             ConstraintViolationException ve = (ConstraintViolationException) e.getCause(); // 里面嵌了一个ConstraintViolationException
  23.             Set<ConstraintViolation<?>> violations = ve.getConstraintViolations(); // 可以拿到一个验证错误详细信息的集合
  24.             System.out.println(violations);
  25.         }
  26.     } 
  27. }

  1. 自 2.1.0 版本开始支持, 如何使用可以参考 dubbo 项目中的示例代码 ↩︎

  2. 验证方式可扩展，扩展方式参见开发者手册中的验证扩展 ↩︎