Java – hibernate – cannot use UserType to execute queries in the where clause

I have a hibernate UserType defined as converting data before it enters our database, and then decompressing it when it is read back from the database This is good when inserting rows or querying rows using row IDs or other methods However, when I try to find records using a query, the parameter binding seems to fail:

org.springframework.dao.InvalidDataAccessApiUsageException: Parameter value [thisIsTheSearchString] did not match expected type [com.xxx.MyUserType (n/a)]; nested exception is java.lang.IllegalArgumentException: Parameter value [thisIsTheSearchString] did not match expected type [com.xxx.MyUserType (n/a)]

I try to implement literaltype and objecttosqlstring methods, but it doesn't look like such methods are called

As a simplified example:

public class MyUserType implements UserType,LiteralType {

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

    @Override
    public Class returnedClass() {
        return MyUserType.class;
    }

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

    @Override
    public int hashCode(Object x) throws HibernateException {
        assert (x != null);
        return x.hashCode();
    }

    @Override
    public Object nullSafeGet(
            ResultSet rs,String[] names,SessionImplementor session,Object owner) 
                    throws HibernateException,sqlException
    {
        assert names.length == 1;
        return untransform( rs.getString( names[0] ); );
    }

    String transform(String untransformed) {
        //...
    }

    String untransform(String transformed) {
        //...
    }

    @Override
    public void nullSafeSet(
            PreparedStatement st,Object value,int index,SessionImplementor session)
                    throws HibernateException,sqlException 
    {
        if ( value == null ) {
            st.setNull(index,Types.VARCHAR);
        } else {
            final String untransformed = (String)value;

            return transform(untransformed);
        }
    }

    @Override
    public Object deepCopy(Object value) throws HibernateException {
        if ( value == null ) {
            return null;
        }
        return (String)value;
    }

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

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

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

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

    // THIS NEVER GETS CALLED
    @Override
    public String objectTosqlString(Object value,Dialect dialect)
            throws Exception 
    {
        if ( value == null ) {
            return null;
        }

        String transformed = transform((String)value);

        StringType stringType = new StringType();
        String sqlString = stringType.objectTosqlString(transformed,dialect);

        return sqlString;
    }
}

The entity looks like:

@Entity
@Table(name = "blah_blah")
@TypeDefs(value = { @TypeDef(name = "transformedText",typeClass = MyUserType.class)})
public class BlahBlah implements Serializable,Persistable<Long> {

    //...

    @Column(name = "transformed")
    @Type(type = "transformedText")
    String transformed;

    //...
}

My query:

@Query(value = 
        "select b " +
        "from BlahBlah b " +
        "where b.transformed = ?1 ")
public List<BlahBlah> findTransformed(String text);

Solution

I think you need to change the returned class:

@Override
public Class returnedClass() {
    return MyUserType.class;
}

should:

@Override
public Class returnedClass() {
    return String.class;
}

In document（ https://docs.jboss.org/hibernate/orm/3.5/api/org/hibernate/usertype/UserType.html#returnedClass In ():