如何用hibernate映射自定义枚举整数序数？

Question

我有一个名为Status的枚举类,如下所示

public enum Status {
    PENDING(0), SUCCESS(1), FAILED(-1);

    private int st;

    private Status(int st){
        this.st = st;
    }
}

从其他类我尝试映射此状态枚举

public void setStatus(Status status) {
        this.status = status;
    }

    @Enumerated(EnumType.ORDINAL)
    public Status getStatus() {
        return status;
    }

当我运行这段代码时,我明白了

java.lang.IllegalArgumentException:enum类数据的未知序数值.Status:-1 org.hibernate.type.EnumType.nullSafeGet(EnumType.java:93)org.hibernate.type.CustomType.nullSafeGet(CustomType.java: 124)在org.hibernate.type.AbstractType.hydrate(AbstractType.java:106)at

但我在枚举定义中已经有-1.

Answer 1

您可以定义自己的UserType定义,以定义Hibernate应如何映射这些枚举.

请注意,序数定义了枚举值的索引,因此FAILED将具有序数2.要使用其属性映射枚举,您需要一个UserType实现.

一些链接:

• https://community.jboss.org/wiki/UserTypeForPersistingAnEnumWithAVARCHARColumn
• http://javadata.blogspot.de/2011/07/hibernate-and-enum-handling.html(查看"Hibernate中的Paramterized Enumeration"部分)

Answer 2

这是一个使用字符串标签而不是int id的解决方案,但是它很容易适应.

public class User { 
    @Id
    private int id;

    @Type(type = "com.example.hibernate.LabeledEnumType")
    private Role role;
}


public enum Role implements LabeledEnum {
    ADMIN("admin"), USER("user"), ANONYMOUS("anon");

    private final String label;

    Role(String label) {
        this.label = label;
    }

    @Override
    public String getLabel() {
        return label;
    }
}


public interface LabeledEnum {
    String getLabel();
}


public final class LabeledEnumType implements DynamicParameterizedType, UserType {

    private Class<? extends Enum> enumClass;

    @Override
    public Object assemble(Serializable cached, Object owner)
            throws HibernateException {
        return cached;
    }

    @Override
    public Object deepCopy(Object value) throws HibernateException {
        return value;
    }

    @Override
    public Serializable disassemble(Object value) throws HibernateException {
        return (Serializable) value;
    }

    @Override
    public boolean equals(Object x, Object y) throws HibernateException {
        return x == y;
    }

    @Override
    public int hashCode(Object x) throws HibernateException {
        return x == null ? 0 : x.hashCode();
    }

    @Override
    public boolean isMutable() {
        return false;
    }

    @Override
    public Object nullSafeGet(ResultSet rs, String[] names, SessionImplementor session, Object owner)
            throws HibernateException, SQLException {
        String label = rs.getString(names[0]);
        if (rs.wasNull()) {
            return null;
        }
        for (Enum value : returnedClass().getEnumConstants()) {
            if (value instanceof LabeledEnum) {
                LabeledEnum labeledEnum = (LabeledEnum) value;
                if (labeledEnum.getLabel().equals(label)) {
                    return value;
                }
            }
        }
        throw new IllegalStateException("Unknown " + returnedClass().getSimpleName() + " label");
    }

    @Override
    public void nullSafeSet(PreparedStatement st, Object value, int index, SessionImplementor session)
            throws HibernateException, SQLException {
        if (value == null) {
            st.setNull(index, Types.VARCHAR);
        } else {
            st.setString(index, ((LabeledEnum) value).getLabel());
        }
    }

    @Override
    public Object replace(Object original, Object target, Object owner)
            throws HibernateException {
        return original;
    }

    @Override
    public Class<? extends Enum> returnedClass() {
        return enumClass;
    }

    @Override
    public int[] sqlTypes() {
        return new int[]{Types.VARCHAR};
    }

    @Override
    public void setParameterValues(Properties parameters) {
        ParameterType params = (ParameterType) parameters.get( PARAMETER_TYPE );
        enumClass = params.getReturnedClass();
    }
}