Hibernate Embeddable 后加载校验：实现组合字段的有效性验证

import javax.persistence.Column;
import javax.persistence.Embeddable;
import javax.persistence.EnumType;
import javax.persistence.Enumerated;
import javax.validation.constraints.NotNull; // 字段级别验证示例

// 示例枚举类型
public enum MyValueType {
    INTEGER_TYPE,
    STRING_TYPE,
    BOOLEAN_TYPE
}

@Embeddable
// 在这里应用自定义的类级别验证注解
@ValidMyEmbeddableCombination
public class MyEmbeddable {

    @NotNull(message = "类型不能为空")
    @Enumerated(EnumType.STRING)
    @Column(name = "embed_type", nullable = false)
    private MyValueType type;

    @Column(name = "embed_value")
    private String value; // 假设数据库存储为字符串

    // Hibernate 要求无参构造函数
    public MyEmbeddable() {
    }

    public MyEmbeddable(MyValueType type, String value) {
        this.type = type;
        this.value = value;
    }

    // Getters and Setters
    public MyValueType getType() {
        return type;
    }

    public void setType(MyValueType type) {
        this.type = type;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.*;

@Target({ElementType.TYPE}) // 目标是类
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = ValidMyEmbeddableCombinationValidator.class) // 关联到具体的验证器
@Documented
public @interface ValidMyEmbeddableCombination {
    String message() default "MyEmbeddable 的类型与值组合无效。"; // 默认错误消息
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
}

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class ValidMyEmbeddableCombinationValidator implements ConstraintValidator<ValidMyEmbeddableCombination, MyEmbeddable> {

    @Override
    public void initialize(ValidMyEmbeddableCombination constraintAnnotation) {
        // 可以在这里初始化验证器，例如获取注解的属性
    }

    @Override
    public boolean isValid(MyEmbeddable embeddable, ConstraintValidatorContext context) {
        // 如果 embeddable 为 null，则通常由 @NotNull 字段级别验证处理
        if (embeddable == null) {
            return true;
        }

        MyValueType type = embeddable.getType();
        String value = embeddable.getValue();

        // 首先检查 type 是否为 null，因为组合验证依赖于 type
        if (type == null) {
            // 如果 type 为 null，说明字段级别 @NotNull 应该捕获到，
            // 但为确保组合验证的逻辑完整性，这里也可以返回 false。
            // 也可以通过 context.buildConstraintViolationWithTemplate() 添加更具体的错误信息
            return false;
        }

        try {
            switch (type) {
                case INTEGER_TYPE:
                    // 如果 type 是 INTEGER_TYPE，value 必须是有效的整数字符串
                    Integer.parseInt(value);
                    return true;
                case STRING_TYPE:
                    // 如果 type 是 STRING_TYPE，value 必须是非空字符串
                    return value != null && !value.trim().isEmpty();
                case BOOLEAN_TYPE:
                    // 如果 type 是 BOOLEAN_TYPE，value 必须是 "true" 或 "false"
                    return "true".equalsIgnoreCase(value) || "false".equalsIgnoreCase(value);
                default:
                    // 遇到未知类型，视为无效
                    return false;
            }
        } catch (NumberFormatException e) {
            // 捕获 INTEGER_TYPE 转换失败的异常
            return false;
        } catch (Exception e) {
            // 捕获其他潜在异常
            return false;
        }
    }
}

import javax.persistence.Embedded;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.validation.Valid; // 关键：启用对嵌入对象的级联验证
import javax.validation.constraints.NotBlank;

@Entity
public class MyEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @NotBlank(message = "名称不能为空")
    private String name;

    @Embedded
    @Valid // 确保 MyEmbeddable 上的验证被触发
    private MyEmbeddable data;

    // Hibernate 要求无参构造函数
    public MyEntity() {
    }

    public MyEntity(String name, MyEmbeddable data) {
        this.name = name;
        this.data = data;
    }

    // Getters and Setters
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public MyEmbeddable getData() {
        return data;
    }

    public void setData(MyEmbeddable data) {
        this.data = data;
    }
}